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Fornwald RM, Yadav A, Montero Bastidas JR, Smith MR, Maleczka RE. Simple and Green Preparation of Tetraalkoxydiborons and Diboron Diolates from Tetrahydroxydiboron. J Org Chem 2024; 89:6048-6052. [PMID: 38640193 PMCID: PMC11077490 DOI: 10.1021/acs.joc.3c02992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 03/27/2024] [Accepted: 04/05/2024] [Indexed: 04/21/2024]
Abstract
Tetraalkoxydiborons can be easily prepared by acid-catalyzed reactions of tetrahydroxydiboron or its anhydride with trialkyl orthoformates. Addition of diols to these reaction mixtures afforded diboron diolates in high yield. In both cases, removal of volatile byproducts is all that is required for the isolation of the diboron. These methods constitute a convenient alternative to previous preparations from tetrakis (dimethylamino) diboron and tetrahydroxydiboron.
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Affiliation(s)
| | | | - Jose R. Montero Bastidas
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East
Lansing, Michigan 48824, United States
| | - Milton R. Smith
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East
Lansing, Michigan 48824, United States
| | - Robert E. Maleczka
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East
Lansing, Michigan 48824, United States
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2
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Chhabra A, Reich S, Shannon TM, Maleczka RE, Smith MR. Access to C(sp 3) borylated and silylated cyclic molecules: hydrogenation of corresponding arenes and heteroarenes. RSC Adv 2024; 14:10590-10607. [PMID: 38567346 PMCID: PMC10985595 DOI: 10.1039/d4ra00491d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 03/15/2024] [Indexed: 04/04/2024] Open
Abstract
This paper presents a simple and cost-effective hydrogenation method for synthesizing a myriad of cycloalkanes and saturated heterocycles bearing boryl or silyl substituents. The catalyst used are heterogeneous, readily available, bench stable, and recyclable. Also demonstrated is the application of the method to compounds that possess both boryl and silyl groups. When combined with Ir-catalyzed sp2 C-H borylation, such hydrogenations offer a two-step complementary alternative to direct sp3 C-H borylations that can suffer selectivity and reactivity issues. Of practical value to the community, complete stereochemical analyses of reported borylated compounds that were never fully characterized are reported herein.
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Affiliation(s)
- Arzoo Chhabra
- Department of Chemistry, Michigan State University 578 S Shaw Lane East Lansing Michigan 48824 USA
| | - Sabrina Reich
- Department of Chemistry, Michigan State University 578 S Shaw Lane East Lansing Michigan 48824 USA
| | - Timothy M Shannon
- Department of Chemistry, Michigan State University 578 S Shaw Lane East Lansing Michigan 48824 USA
| | - Robert E Maleczka
- Department of Chemistry, Michigan State University 578 S Shaw Lane East Lansing Michigan 48824 USA
| | - Milton R Smith
- Department of Chemistry, Michigan State University 578 S Shaw Lane East Lansing Michigan 48824 USA
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3
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O'Connell AC, Mansour PA, Maleczka RE, Smith MR. Regiochemical Switching in Ir-Catalyzed C-H Borylation by Altering Ligand Loadings of N,B-Type Diboron Species. Org Lett 2023; 25:8057-8061. [PMID: 37939287 DOI: 10.1021/acs.orglett.3c02760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Traditional reaction conditions in Ir-catalyzed C-H borylation consist of a 2:1 ligand to Ir metal ratio, affording C(sp2)-H borylation at the least sterically hindered position. We found that lowering the ligand to metal ratio of a N,B-type diboron (BB) preligand in respect to the IrI precatalyst to 0.5:1 affords the chelate controlled ortho product. Switching from steric-directed to chelate-directed products is shown for various substituted arenes and (hetero)arenes containing Lewis-basic functionalities. This work offers the first example of obtaining complementary regioisomers as the major product by altering the ligand loading in CHB.
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Affiliation(s)
- Alex C O'Connell
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing 48824-1322, Michigan United States
| | - Pauline A Mansour
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing 48824-1322, Michigan United States
| | - Robert E Maleczka
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing 48824-1322, Michigan United States
| | - Milton R Smith
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing 48824-1322, Michigan United States
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4
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Dannatt JE, Yadav A, Smith MR, Maleczka RE. Amide directed iridium C(sp 3)-H borylation catalysis with high N-methyl selectivity. Tetrahedron 2022; 109:132578. [PMID: 36684041 PMCID: PMC9854009 DOI: 10.1016/j.tet.2021.132578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A bidentate monoanionic ligand system was developed to enable iridium catalyzed C(sp3)-H activation borylation of N-methyl amides. Borylated amides were obtained in moderate to good isolated yields, and exclusive mono-borylation allowed the amide to be the limiting reagent. Selectivity for C(sp3)-H activation was demonstrated in the presence of sterically available C(sp3)-H bonds. Competitive kinetic isotope studies revealed a large primary isotope effect, implicating C-H activation as the rate limiting step.
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Affiliation(s)
- Jonathan E. Dannatt
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, MI, 48824-1322, USA,Department of Chemistry, University of Dallas, 1845 East Northgate Drive, Irving, TX, 75062, USA
| | - Anshu Yadav
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, MI, 48824-1322, USA
| | - Milton R. Smith
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, MI, 48824-1322, USA,Corresponding author. (M.R. Smith), (R.E. Maleczka)
| | - Robert E. Maleczka
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, MI, 48824-1322, USA,Corresponding author
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5
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Bastidas JRM, Chhabra A, Feng Y, Oleskey TJ, Smith MR, Maleczka RE. Steric Shielding Effects Induced by Intramolecular C-H⋯O Hydrogen Bonding: Remote Borylation Directed by Bpin Groups. ACS Catal 2022; 12:2694-2705. [PMID: 36685107 PMCID: PMC9854017 DOI: 10.1021/acscatal.1c05701] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Regioselectivities in catalytic C-H borylations (CHBs) have been rationalized using simplistic steric models and correlations with nuclear magnetic resonance (NMR) chemical shifts. However, regioselectivity can be significant for important substrate classes where none would be expected from these arguments. In this study, intramolecular hydrogen bonding (IMHB) can lead to steric shielding effects that can direct Ir-catalyzed CHB regiochemistry. Bpin (Bpin = pinacol boronic ester)/arene IMHB can promote remote borylations of N-borylated anilines, 2-amino-N-alkylpyridine, tetrahydroquinolines, indoles, and 1-borylated naphthalenes. Experimental and computational studies support molecular geometries with the Bpin orientation controlled by a C-H⋯O IMHB. IMHB-directed remote CHB appeared operative in the C6 borylation of 3-aminoindazole (seven-membered IMHB) and C6 borylation of an osimertinib analogue where a pyrimidine IMHB creates the steric shield. This study informs researchers to evaluate not only inter- but also intramolecular noncovalent interactions as potential drivers of remote CHB regioselectivity.
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Affiliation(s)
| | - Arzoo Chhabra
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Yilong Feng
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Thomas J. Oleskey
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Milton R. Smith
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Robert E. Maleczka
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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6
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Jayasundara CRK, Gil-Negrete JM, Montero Bastidas JR, Chhabra A, Martínez MM, Pérez Sestelo J, Smith MR, Maleczka RE. Merging Iridium-Catalyzed C-H Borylations with Palladium-Catalyzed Cross-Couplings Using Triorganoindium Reagents. J Org Chem 2021; 87:751-759. [PMID: 34889604 DOI: 10.1021/acs.joc.1c01978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A versatile and efficient method to prepare borylated arenes furnished with alkyl, alkenyl, alkynyl, aryl, and heteroaryl functional groups is developed by merging Ir-catalyzed C-H borylations (CHB) with a chemoselective palladium-catalyzed cross-coupling of triorganoindium reagents (Sarandeses-Sestelo coupling) with aryl halides bearing a boronic ester substituent. Using triorganoindium cross-coupling reactions to introduce unsaturated moieties enables the synthesis of borylated arenes that would be difficult to access through the direct application of the CHB methodology. The sequential double catalyzed procedure can be also performed in one vessel.
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Affiliation(s)
| | - José M Gil-Negrete
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Universidade da Coruña, E-15071 A Coruña, Spain
| | - Jose R Montero Bastidas
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
| | - Arzoo Chhabra
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
| | - M Montserrat Martínez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Universidade da Coruña, E-15071 A Coruña, Spain
| | - José Pérez Sestelo
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Universidade da Coruña, E-15071 A Coruña, Spain
| | - Milton R Smith
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
| | - Robert E Maleczka
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
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7
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Abstract
4-Silyl-5,6-dihydropyrans undergo remarkably selective [1,4]-Wittig rearrangements to give silylcyclopropanes in good yields. The selectivity is independent of the silyl group, but it is influenced by the electronic character of the migrating center. Electron-rich and electron-neutral (hetero)aryl groups and aliphatic substituents at the migrating center lead to exclusive [1,4]-migration, whereas electron-deficient aryl groups predominantly afford [1,2]-Wittig products.
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Affiliation(s)
- Luis M Mori-Quiroz
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Emmanuel W Maloba
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Robert E Maleczka
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
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8
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Bastidas JRM, Oleskey TJ, Miller SL, Smith MR, Maleczka RE. Para-Selective, Iridium-Catalyzed C-H Borylations of Sulfated Phenols, Benzyl Alcohols, and Anilines Directed by Ion-Pair Electrostatic Interactions. J Am Chem Soc 2019; 141:15483-15487. [PMID: 31525037 PMCID: PMC9851420 DOI: 10.1021/jacs.9b08464] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Para C-H borylations (CHB) of tetraalkylammonium sulfates and sulfamates have been achieved using bipyridine-ligated Ir boryl catalysts. Selectivities can be modulated by both the length of the alkyl groups in the tetraalkylammonium cations and the substituents on the bipyridine ligands. Ion pairing, where the alkyl groups of the cation shield the meta C-H bonds in the counteranions, is proposed to account for para selectivity. The 4,4'-dimethoxy-2,2'-bipyridine ligand gave superior selectivities.
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9
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Miller SL, Chotana GA, Fritz JA, Chattopadhyay B, Maleczka RE, Smith MR. C-H Borylation Catalysts that Distinguish Between Similarly Sized Substituents Like Fluorine and Hydrogen. Org Lett 2019; 21:6388-6392. [PMID: 31393137 PMCID: PMC9864527 DOI: 10.1021/acs.orglett.9b02299] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
By modifying ligand steric and electronic profiles it is possible to C-H borylate ortho or meta to substituents in aromatic and heteroaromatic compounds, where steric differences between accessible C-H sites are small. Dramatic effects on selectivities between reactions using B2pin2 or 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (HBpin) are described for the first time. Judicious ligand and borane combinations give highly regioselective C-H borylations on substrates where typical borylation protocols afford poor selectivities.
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10
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Vogelsang DF, Maleczka RE, Lee A. Predictive Liquid Chromatography Separation for Mixtures of Functionalized Double-Decker Shaped Silsesquioxanes Based on HPLC Chromatograms. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.8b05490] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David F. Vogelsang
- Department of Chemical Engineering and Materials Science, Michigan State University, Engineering Building, 428 South Shaw Lane, Room 2100, East Lansing, Michigan 48824-1226 United States
| | - Robert E. Maleczka
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
| | - Andre Lee
- Department of Chemical Engineering and Materials Science, Michigan State University, Engineering Building, 428 South Shaw Lane, Room 2100, East Lansing, Michigan 48824-1226 United States
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11
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Barry BD, Dannatt JE, King AK, Lee A, Maleczka RE. A general diversity oriented synthesis of asymmetric double-decker shaped silsesquioxanes. Chem Commun (Camb) 2019; 55:8623-8626. [PMID: 31282512 DOI: 10.1039/c9cc03972d] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A strategically novel synthesis of nano-sized, asymmetrically functionalized double-decker shaped silsesquioxanes (DDSQ) is reported. Selective protection with a boronic acid affords the crucial mono-protected intermediate en route to the asymmetric products. Generation of symmetric by-products is minimized by judicious choice of base, and high recovery of recyclable starting DDSQ tetraol is achieved.
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Affiliation(s)
- Badru-Deen Barry
- Department of Chemistry, Michigan State University, 578 S. Shaw Ln, East Lansing, Michigan 48824-1322, USA.
| | - Jonathan E Dannatt
- Department of Chemistry, Michigan State University, 578 S. Shaw Ln, East Lansing, Michigan 48824-1322, USA.
| | - Austin K King
- Department of Chemistry, Michigan State University, 578 S. Shaw Ln, East Lansing, Michigan 48824-1322, USA.
| | - Andre Lee
- Department of Chemical Engineering and Materials Science, Michigan State University, 428 S. Shaw Ln, East Lansing, Michigan 48824-1226, USA.
| | - Robert E Maleczka
- Department of Chemistry, Michigan State University, 578 S. Shaw Ln, East Lansing, Michigan 48824-1322, USA.
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13
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Smith MR, Bisht R, Haldar C, Pandey G, Dannatt JE, Ghaffari B, Maleczka RE, Chattopadhyay B. Achieving High Ortho Selectivity in Aniline C-H Borylations by Modifying Boron Substituents. ACS Catal 2018; 8:6216-6223. [PMID: 30147990 DOI: 10.1021/acscatal.8b00641] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
High ortho selectivity for Ir-catalyzed C-H borylations (CHBs) of anilines results when B2eg2 (eg = ethylene glycolate) is used as the borylating reagent in lieu of B2pin2, which is known to give isomeric mixtures with anilines lacking a blocking group at the 4-position. With this modification, high selectivities and good yields are now possible for various anilines, including those with groups at the 2- and 3-positions. Experiments indicate that ArylN(H)Beg species are generated prior to CHB and support the improved ortho selectivity relative to B2pin2 reactions arising from smaller Beg ligands on the Ir catalyst. The lowest-energy transition states (TSs) from density functional theory computational analyses have N-H···O hydrogen-bonding interactions between PhN(H)Beg and O atoms in Beg ligands. Ir-catalyzed CHB of PhN(H)Me with B2eg2 is also highly ortho-selective. 1H NMR experiments show that N-borylation fully generates PhN(Me)Beg prior to CHB. The TS with the lowest Gibbs energy was the ortho TS, in which the Beg unit is oriented anti to the bipyridine ligand.
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Affiliation(s)
- Milton R. Smith
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Ranjana Bisht
- Division of Molecular Synthesis & Drug Discovery, Centre of Bio-Medical Research (CBMR), SGPGIMS Campus, Raebareli Road, Lucknow 226 014, UP, India
- Department of Applied Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow 226 025, UP, India
| | - Chabush Haldar
- Division of Molecular Synthesis & Drug Discovery, Centre of Bio-Medical Research (CBMR), SGPGIMS Campus, Raebareli Road, Lucknow 226 014, UP, India
| | - Gajanan Pandey
- Department of Applied Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow 226 025, UP, India
| | - Jonathan E. Dannatt
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Behnaz Ghaffari
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Robert E. Maleczka
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Buddhadeb Chattopadhyay
- Division of Molecular Synthesis & Drug Discovery, Centre of Bio-Medical Research (CBMR), SGPGIMS Campus, Raebareli Road, Lucknow 226 014, UP, India
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14
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Jayasundara CRK, Sabasovs D, Staples RJ, Oppenheimer J, Smith MR, Maleczka RE. Cobalt-Catalyzed C–H Borylation of Alkyl Arenes and Heteroarenes Including the First Selective Borylations of Secondary Benzylic C–H Bonds. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00144] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chathurika R. K. Jayasundara
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Dmitrijs Sabasovs
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Richard J. Staples
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Jossian Oppenheimer
- The Dow Chemical Company, Process Chemistry & Development, Core R&D, Midland, Michigan 48674, United States
| | - Milton R. Smith
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Robert E. Maleczka
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
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15
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Chattopadhyay B, Dannatt JE, Andujar-De Sanctis IL, Gore KA, Maleczka RE, Singleton DA, Smith MR. Ir-Catalyzed ortho-Borylation of Phenols Directed by Substrate-Ligand Electrostatic Interactions: A Combined Experimental/in Silico Strategy for Optimizing Weak Interactions. J Am Chem Soc 2017; 139:7864-7871. [PMID: 28453268 DOI: 10.1021/jacs.7b02232] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A strategy for affecting ortho versus meta/para selectivity in Ir-catalyzed C-H borylations (CHBs) of phenols is described. From selectivity observations with ArylOBpin (pin = pinacolate), it is hypothesized that an electrostatic interaction between the partial negatively charged OBpin group and the partial positively charged bipyridine ligand of the catalyst favors ortho selectivity. Experimental and computational studies designed to test this hypothesis support it. From further computational work a second generation, in silico designed catalyst emerged, where replacing Bpin with Beg (eg = ethylene glycolate) was predicted to significantly improve ortho selectivity. Experimentally, reactions employing B2eg2 gave ortho selectivities > 99%. Adding triethylamine significantly improved conversions. This ligand-substrate electrostatic interaction provides a unique control element for selective C-H functionalization.
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Affiliation(s)
- Buddhadeb Chattopadhyay
- Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States.,Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, Sanjay Gandhi Post Graduate Institute of Medical Sciences , Raebareli Road, Lucknow, Uttar Pradesh 226014, India
| | - Jonathan E Dannatt
- Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
| | | | - Kristin A Gore
- Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
| | - Robert E Maleczka
- Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
| | - Daniel A Singleton
- Department of Chemistry, Texas A&M University , PO Box 30012, College Station, Texas 77842, United States
| | - Milton R Smith
- Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
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17
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Shen F, Tyagarajan S, Perera D, Krska SW, Maligres PE, Smith MR, Maleczka RE. Bismuth Acetate as a Catalyst for the Sequential Protodeboronation of Di- and Triborylated Indoles. Org Lett 2016; 18:1554-7. [PMID: 26998615 DOI: 10.1021/acs.orglett.6b00356] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bismuth(III) acetate is a safe, inexpensive, and selective facilitator of sequential protodeboronations, which when used in conjunction with Ir-catalyzed borylations allows access to a diversity of borylated indoles. The versatility of combining Ir-catalyzed borylations with Bi(III)-catalyzed protodeboronation is demonstrated by selectively converting 6-fluoroindole into products with Bpin groups at the 4-, 5-, 7-, 2,7-, 4,7-, 3,5-, and 2,4,7-positions and the late-stage functionalization of sumatriptan.
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Affiliation(s)
- Fangyi Shen
- Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Sriram Tyagarajan
- Department of Process Chemistry, Merck Research Laboratories , Rahway, New Jersey 07065, United States
| | - Damith Perera
- Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Shane W Krska
- Department of Process Chemistry, Merck Research Laboratories , Rahway, New Jersey 07065, United States
| | - Peter E Maligres
- Department of Process Chemistry, Merck Research Laboratories , Rahway, New Jersey 07065, United States
| | - Milton R Smith
- Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Robert E Maleczka
- Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824, United States
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18
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Ghaffari B, Vanchura BA, Chotana GA, Staples RJ, Holmes D, Maleczka RE, Smith MR. Reversible Borylene Formation from Ring Opening of Pinacolborane and Other Intermediates Generated from Five-Coordinate Tris-Boryl Complexes: Implications for Catalytic C-H Borylation. Organometallics 2015; 34:4732-4740. [PMID: 28190912 DOI: 10.1021/acs.organomet.5b00525] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Catalytic C-H borylation using the five-coordinate tris-boryl complex (dippe)Ir(Bpin)3 (5a, dippe = 1,2-bis(diisopropylphosphino)ethane) has been examined using 31P{1H} and 1H NMR spectroscopy. Compound 5a was shown to react rapidly and reversibly with HBpin to generate a six-coordinate borylene complex, (dippe)Ir(H)-(Bpin)2(BOCMe2CMe2OBpin) (6), whose structure was confirmed by X-ray crystallography. Under catalytic conditions, the H2 generated from C-H borylation converted compound 6 to a series of intermediates. The first is tentatively assigned from 31P{1H} and 1H NMR spectra as (dippe)Ir(H2B3pin3) (7), which is the product of formal H2 addition to compound 5a. As catalysis progressed, compound 7 was converted to a new species with the formula (dippe)Ir(H3B2pin2) (8), which arose from H2 addition to compound 7 with loss of HBpin. Compound 8 was characterized by 31P{1H} and 1H NMR spectroscopy, and its structure was confirmed by X-ray crystallography, where two molecules with different ligand orientations were found in the unit cell. DFT calculations support the formulation of compound 8 as an IrIII agostic borane complex, (dippe)IrH2(Bpin)(η2-HBpin). Compound 8 was gradually converted to (dippe)Ir(H4Bpin) (9), which was characterized by 31P{1H} and 1H NMR spectroscopy and X-ray crystallography. DFT calculations favor its formulation as an agostic borane complex of IrIII with the formula (dippe)IrH3(η2-HBpin). Compound 9 reacted further with H2 to afford the dimeric structure [(dippe)IrH2(μ2-H)]2 (10), which was characterized by 1H NMR and X-ray crystallography. Compounds 7-10 are in equilibrium when H2 and HBpin are present.
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Affiliation(s)
- Behnaz Ghaffari
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
| | - Britt A Vanchura
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
| | - Ghayoor A Chotana
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
| | - Richard J Staples
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
| | - Daniel Holmes
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
| | - Robert E Maleczka
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
| | - Milton R Smith
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322 United States
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19
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Kallepalli VA, Gore KA, Shi F, Sanchez L, Chotana GA, Miller SL, Maleczka RE, Smith MR. Harnessing C-H Borylation/Deborylation for Selective Deuteration, Synthesis of Boronate Esters, and Late Stage Functionalization. J Org Chem 2015; 80:8341-53. [PMID: 26226056 PMCID: PMC5080619 DOI: 10.1021/acs.joc.5b01588] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ir-catalyzed deborylation can be used to selectively deuterate aromatic and heteroaromatic substrates. Combined with the selectivities of Ir-catalyzed C-H borylations, uniquely labeled compounds can be prepared. In addition, diborylation/deborylation reactions provide monoborylated regioisomers that complement those prepared by C-H borylation. Comparisons between Ir-catalyzed deborylations and Pd-catalyzed deborylations of diborylated indoles described by Movassaghi are made. The Ir-catalyzed process is more effective for deborylating aromatics and is generally more effective in the monodeborylation of diborylated thiophenes. These processes can be applied to complex molecules such as clopidogrel.
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Affiliation(s)
- Venkata A Kallepalli
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Kristin A. Gore
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Feng Shi
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Luis Sanchez
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Ghayoor A. Chotana
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Susanne L. Miller
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Robert E. Maleczka
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Milton R. Smith
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824-1322, United States
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20
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Mori-Quiroz LM, Maleczka RE. Stereoconvergent [1,2]- and [1,4]-Wittig rearrangements of 2-silyl-6-aryl-5,6-dihydropyrans: a tale of steric vs electronic regiocontrol of divergent pathways. J Org Chem 2015; 80:1163-91. [PMID: 25490725 PMCID: PMC4301091 DOI: 10.1021/jo5026942] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Indexed: 11/29/2022]
Abstract
The regiodivergent ring contraction of diastereomeric 2-silyl-5,6-dihydro-6-aryl-(2H)-pyrans via [1,2]- and [1,4]-Wittig rearrangements to the corresponding α-silylcyclopentenols or (α-cyclopropyl)acylsilanes favor the [1,4]-pathway by ortho and para directing groups in the aromatic appendage and/or by sterically demanding silyl groups. The [1,2]-pathway is dominant with meta directing or electron-poor aromatic moieties. Exclusive [1,2]-Wittig rearrangements are observed when olefin substituents proximal to the silyl are present. cis and trans diastereomers exhibit different reactivities, but converge to a single [1,2]- or [1,4]-Wittig product with high diastereoselectivity and yield.
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Affiliation(s)
- Luis M. Mori-Quiroz
- Department of Chemistry, Michigan
State University, 578
South Shaw Lane, East
Lansing, Michigan 48824, United States
| | - Robert E. Maleczka
- Department of Chemistry, Michigan
State University, 578
South Shaw Lane, East
Lansing, Michigan 48824, United States
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21
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Abstract
A two-step Ir-catalyzed borylation/Pd-catalyzed dehalogenation sequence allows for the net synthesis of fluoroarenes where the boronic ester is ortho to fluorine. Key elements of this approach include the use of a halogen para to the fluorine to block meta Ir-catalyzed borylation and the chemoselective Pd-catalyzed dehalogenation by KF activated polymethylhydrosiloxane (PMHS).
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Affiliation(s)
- Chathurika
R. K. Jayasundara
- Department
of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Jason M. Unold
- Department
of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Jossian Oppenheimer
- The
Dow Chemical Company, Process Chemistry
& Development, Core R&D, Midland, Michigan 48674, United States
| | - Milton R. Smith
- Department
of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
| | - Robert E. Maleczka
- Department
of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States
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22
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Ghaffari B, Preshlock SM, Plattner DL, Staples R, Maligres PE, Krska SW, Maleczka RE, Smith MR. Silyl phosphorus and nitrogen donor chelates for homogeneous ortho borylation catalysis. J Am Chem Soc 2014; 136:14345-8. [PMID: 25141136 PMCID: PMC4210111 DOI: 10.1021/ja506229s] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Indexed: 12/17/2022]
Abstract
Ir catalysts supported by bidentate silyl ligands that contain P- or N-donors are shown to effect ortho borylations for a range of substituted aromatics. The substrate scope is broad, and the modular ligand synthesis allows for flexible catalyst design.
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Affiliation(s)
- Behnaz Ghaffari
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
| | - Sean M. Preshlock
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
| | - Donald L. Plattner
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
| | - Richard
J. Staples
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
| | - Peter E. Maligres
- Department of Process Chemistry, Merck Research Laboratories, Rahway, New Jersey 07065, United States
| | - Shane W. Krska
- Department of Process Chemistry, Merck Research Laboratories, Rahway, New Jersey 07065, United States
| | - Robert E. Maleczka
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
| | - Milton R. Smith
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, United States
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23
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Ghosh B, Amado-Sierra MDRI, Holmes D, Maleczka RE. A one-pot allylation-hydrostannation sequence with recycling of the intermediate tin waste. Org Lett 2014; 16:2318-21. [PMID: 24725171 DOI: 10.1021/ol500460u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A one-pot allylation and hydrostannation of alkynals where the tin byproduct formed in the first step of the reaction is recycled and used in the second step of the sequence is presented. Specifically, a BF3·OEt2-promoted allylstannation of the aldehyde moiety in the alkynal is followed by the introduction of polymethylhydrosiloxane (PMHS) and catalytic B(C6F5)3, which convert the tin byproduct of the allylation into Bu3SnH, which then hydrostannates the alkyne in the molecule. (119)Sn and (11)B NMR data suggest an organotin fluoride species is formed during the allylation step and involved in the tin recycling step.
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Affiliation(s)
- Banibrata Ghosh
- Department of Chemistry, Michigan State University , 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
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24
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Preshlock SM, Plattner DL, Maligres PE, Krska SW, Maleczka RE, Smith MR. A Traceless Directing Group for CH Borylation. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201306511] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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25
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Preshlock SM, Plattner DL, Maligres PE, Krska SW, Maleczka RE, Smith MR. A traceless directing group for C-H borylation. Angew Chem Int Ed Engl 2013; 52:12915-9. [PMID: 24222178 DOI: 10.1002/anie.201306511] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 09/26/2013] [Indexed: 11/12/2022]
Abstract
Not a trace: Borylation of the nitrogen in nitrogen heterocycles or anilines provides a traceless directing group for subsequent catalytic C-H borylation. Selectivities that previously required Boc protection can be achieved; furthermore, the NBpin directing group can be installed and removed in-situ, and product yields are substantially higher. Boc=tert-butoxycarbonyl, pin=pinacolato.
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Affiliation(s)
- Sean M Preshlock
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824-1322 (USA)
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26
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Ghosh B, Maleczka RE. Corrigendum to: “Ni, Co, and Mo-catalyzed alkyne hydrostannations using Bu3SnCl/PMHS/KF/18-crown-6 as an in situ Bu3SnH source” [Tetrahedron Lett. 52 (2011), 5285–5287]. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.04.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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27
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Preshlock SM, Ghaffari B, Maligres PE, Krska SW, Maleczka RE, Smith MR. High-Throughput Optimization of Ir-Catalyzed C–H Borylation: A Tutorial for Practical Applications. J Am Chem Soc 2013; 135:7572-82. [DOI: 10.1021/ja400295v] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Sean M. Preshlock
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322,
United States
| | - Behnaz Ghaffari
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322,
United States
| | - Peter E. Maligres
- Department
of Process Chemistry, Merck Research Laboratories, Rahway, New Jersey 07065,
United States
| | - Shane W. Krska
- Department
of Process Chemistry, Merck Research Laboratories, Rahway, New Jersey 07065,
United States
| | - Robert E. Maleczka
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322,
United States
| | - Milton R. Smith
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322,
United States
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28
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Onyeozili EN, Mori-Quiroz LM, Maleczka RE. [1,2]- and [1,4]-Wittig Rearrangements of α-Alkoxysilanes: Effect of Substitutions at both the Migrating Benzylic Carbon and the Terminal sp 2 Carbon of the Allyl Moiety. Tetrahedron 2013; 69:849-860. [PMID: 23459008 PMCID: PMC3580876 DOI: 10.1016/j.tet.2012.10.091] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Substituted α-alkoxysilanes can be deprotonated by alkyllithium bases and made to undergo Wittig rearrangements to afford the #x0005B;1,4]- and [1,2]-rearranged products in varying ratios. Substitution at the benzylic migrating carbon and/or at the allylic carbon of the allyl moiety impacts the rearrangement reaction, influencing the reactivity as well as the [1,4]-/[1,2]-selectivity. Diastereomeric α-alkoxysilanes show different reactivities with the syn diastereomer being the more reactive isomer.
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Affiliation(s)
- Edith N. Onyeozili
- Department of Chemistry, Florida A&M University, Tallahassee, FL 32307 USA
| | - Luis M. Mori-Quiroz
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824 USA
| | - Robert E. Maleczka
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824 USA
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29
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Abstract
The NHBoc group affords ortho selective C-H borylations in arenes and alkenes. Experimental and computational studies support an outer sphere mechanism where the N-H proton hydrogen bonds to a boryl ligand oxygen. The regioselectivities are unique and complement those of directed ortho metalations.
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Affiliation(s)
- Philipp C Roosen
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, USA
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30
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Norberg AM, Smith MR, Maleczka RE. Practical One-Pot C-H Activation/Borylation/Oxidation: Preparation of 3-Bromo-5-methylphenol on a Multigram Scale. SYNTHESIS-STUTTGART 2011; 2011:857-859. [PMID: 27746513 DOI: 10.1055/s-0030-1258443] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A practical one-pot C-H activation/borylation/oxidation sequence for the generation of 3,5-disubstituted phenols is presented. Specifically, 3-bromo-5-methylphenol is prepared from 3-bromotoluene, without isolation of intermediates, on a multigram scale, and in high yield. The process proceeds under mild conditions and can be completed within one day.
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Affiliation(s)
- A Monica Norberg
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Milton R Smith
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Robert E Maleczka
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
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31
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Abstract
Catalytic Pd(OAc)(2) and polymethylhydrosiloxane (PMHS), in conjunction with aqueous KF, and a catalytic amount of an aromatic chloride, effects the chemo-, regio-, and stereoselective deoxygenation of benzylic oxygenated substrates at room temperature in THF. Preliminary mechanistic experiments suggest the process to involve palladium-nanoparticle-catalyzed hydrosilylation followed by C-O reduction. The chloroarene additive appears to facilitate the hydrogenolysis process through the slow controlled release of HCl.
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Affiliation(s)
| | - Robert E. Maleczka
- Department of Chemistry, Michigan State University, East Lansing, MI 48824
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32
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Vanchura BA, Preshlock SM, Roosen PC, Kallepalli VA, Staples RJ, Maleczka RE, Singleton DA, Smith MR. Electronic effects in iridium C-H borylations: insights from unencumbered substrates and variation of boryl ligand substituents. Chem Commun (Camb) 2010; 46:7724-6. [PMID: 20852803 DOI: 10.1039/c0cc02041a] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Experiment and theory favour a model of C-H borylation where significant proton transfer character exists in the transition state.
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Affiliation(s)
- Britt A Vanchura
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, USA
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33
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Kallepalli VA, Shi F, Paul S, Onyeozili EN, Maleczka RE, Smith MR. Boc groups as protectors and directors for Ir-catalyzed C-H borylation of heterocycles. J Org Chem 2010; 74:9199-201. [PMID: 19894699 DOI: 10.1021/jo901822b] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ir-catalyzed C-H borylation is found to be compatible with Boc protecting groups. Thus, pyrroles, indoles, and azaindoles can be selectively functionalized at C-H positions beta to N. The Boc group can be removed on thermolysis or left intact during subsequent transformations.
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Affiliation(s)
- Venkata A Kallepalli
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, USA
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34
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35
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E. Maleczka R, R. Smith M, A. Kallepalli V, Sánchez L, Li H, J. Gesmundo N. Divergent Synthesis of 2,3,5-Substituted Thiophenes by C-H Activation/Borylation/Suzuki Coupling. HETEROCYCLES 2010. [DOI: 10.3987/com-09-s(s)135] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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36
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Chotana GA, Vanchura BA, Tse MK, Staples RJ, Maleczka RE, Smith MR. Getting the sterics just right: a five-coordinate iridium trisboryl complex that reacts with C-H bonds at room temperature. Chem Commun (Camb) 2009:5731-3. [PMID: 19774251 DOI: 10.1039/b914736e] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Five-coordinate boryl complexes relevant to Ir mediated C-H borylations have been synthesized, providing a glimpse of the most fundamental step in the catalytic cycle for the first time.
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Affiliation(s)
- Ghayoor A Chotana
- Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, USA
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37
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Affiliation(s)
- Robert E. Maleczka
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
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38
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Norberg AM, Sanchez L, Maleczka RE. Aryl-aryl crosss-couplings that avoid the preparation of haloaromatics. Curr Opin Drug Discov Devel 2008; 11:853-869. [PMID: 18946848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Advances in the development of cross-coupling protocols that avoid haloaromatics are reviewed. Most of the reports that are discussed appeared in the literature within the past 2 years and describe either alternatives to halogenated electrophiles or halogen-free preparations of the organometallic partners. However, while this review is not limited to cross-couplings that are entirely free of haloaromatics, coverage of the topic is largely restricted to reactions affording new aryl-aryl, aryl-heteroaryl and heteroaryl-heteroaryl carbon-carbon bonds during the cross-coupling event.
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Affiliation(s)
- A Monica Norberg
- Michigan State University, Department of Chemistry, 540 Chemistry, East Lansing, MI 48824, USA
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39
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Chotana GA, Kallepalli VA, Maleczka RE, Smith MR. Iridium-catalyzed borylation of thiophenes: versatile, synthetic elaboration founded on selective C-H functionalization. Tetrahedron 2008; 64. [PMID: 24385669 DOI: 10.1016/j.tet.2008.02.111] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Iridium-catalyzed borylation has been applied to various substituted thiophenes to synthesize poly-functionalized thiophenes in good to excellent yields. Apart from common functionalities compatible with iridium-catalyzed borylations, additional functional group tolerance to acyl (COMe), and trimethylsilyl (TMS) groups was also observed. High regioselectivities were observed in borylation of 3-and 2,5-di-substituted thiophenes. Electrophilic aromatic C-H/C-Si bromination on thiophene boronate esters is shown to take place without breaking the C-B bond, and one-pot C-H borylation/Suzuki-Miyaura cross-coupling has been accomplished on 2- and 3-borylated thiophenes.
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Affiliation(s)
- Ghayoor A Chotana
- Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, USA
| | - Venkata A Kallepalli
- Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, USA
| | - Robert E Maleczka
- Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, USA
| | - Milton R Smith
- Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, USA
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40
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Abstract
[reaction: see text] Contrary to previous reports, polymethylhydrosiloxane (PMHS) under Pd(0) catalysis can efficiently reduce aryl acid chlorides to their corresponding aldehydes without requiring an additional reductant, provided the reactions are run in the presence of fluoride.
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Affiliation(s)
- Kyoungsoo Lee
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
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41
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Paul S, Chotana GA, Holmes D, Reichle RC, Maleczka RE, Smith MR. Ir-Catalyzed Functionalization of 2-Substituted Indoles at the 7-Position: Nitrogen-Directed Aromatic Borylation. J Am Chem Soc 2006; 128:15552-3. [PMID: 17147340 DOI: 10.1021/ja0631652] [Citation(s) in RCA: 227] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ir-catalyzed borylation of 2-substituted indoles selectively yields 7-borylated products in good yields. N-Protection, required for previous functionalizations of 2-substituted indoles, is unnecessary.
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Affiliation(s)
- Sulagna Paul
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, USA
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42
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Abstract
[reaction: see text] Room-temperature reduction of aromatic nitro groups to amines can be accomplished in high yield, with wide functional group tolerance and short reaction times (30 min) using a combination of palladium(II) acetate, aqueous potassium fluoride, and polymethylhydrosiloxane (PMHS). Replacing PMHS/KF with triethylsilane allows aliphatic nitro groups to be reduced to their hydroxylamines.
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Affiliation(s)
- Ronald J Rahaim
- Department of Chemistry, Michigan State University, East Lansing, 48824, USA
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44
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Abstract
alpha-Benzyloxyallylsilane undergoes efficient [1,4]-Wittig rearrangement to generate an enolate intermediate that can be trapped with various electrophiles, thereby providing a new synthetic approach to substituted acylsilanes.
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Affiliation(s)
- Edith N Onyeozili
- Department of Chemistry, Michigan State University, 540 Chemistry, East Lansing, Michigan 48824, USA
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45
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Lee K, Gallagher WP, Toskey EA, Chong W, Maleczka RE. One-pot Pd-catalyzed hydrostannation/Stille reaction with acid chlorides as the electrophiles. J Organomet Chem 2006. [DOI: 10.1016/j.jorganchem.2005.11.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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46
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47
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Abstract
[reaction: see text] 5-Substituted 3-amidophenols are prepared by subjecting 3-substituted halobenzenes to an Ir-catalyzed aromatic borylation, followed by a Pd-catalyzed amidation, and finally an oxidation of the boronic ester intermediate. The entire C-H activation borylation/amidation/oxidation sequence can be accomplished without isolation of any intermediate arenes. Usefully, amide partners can include lactams, carbamates, and ureas.
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Affiliation(s)
- Feng Shi
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
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48
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Holmes D, Chotana GA, Maleczka RE, Smith MR. One-Pot Borylation/Amination Reactions: Syntheses of Arylamine Boronate Esters from Halogenated Arenes. Org Lett 2006; 8:1407-10. [PMID: 16562903 DOI: 10.1021/ol060205y] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] A one-pot protocol for converting 1,3- and 1,4-substituted aryl halides to arylamine boronate esters is described. This is achieved by sequential Ir-catalyzed aromatic borylation at the least hindered C-H bond of the aryl halide and subsequent Pd-catalyzed C-N coupling at the halide position of the crude arylboronic ester.
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Affiliation(s)
- Daniel Holmes
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
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49
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Luster-Teasley SL, Ganey PE, DiOrio M, Ward JS, Maleczka RE, Trosko JE, Masten SJ. Effect of byproducts from the ozonation of pyrene: biphenyl-2,2',6,6'-tetracarbaldehyde and biphenyl-2,2',6,6'-tetracarboxylic acid on gap junction intercellular communication and neutrophil function. Environ Toxicol Chem 2005; 24:733-740. [PMID: 15786580 DOI: 10.1897/04-679.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In this study, biphenyl-2,2',6,6'-tetracarbaldehyde, an initial byproduct formed from the ozonation of pyrene, and biphenyl-2,2',6,6'-tetracarboxylic acid, a subsequent pyrene ozonation byproduct, were evaluated using two toxicology assays to compare the toxicity of ozonation byproducts with that of the parent compound. The first assay measured the potential for the compounds to block gap junctional intercellular communication (GJIC) using the scrape loading/dye transfer technique in normal WB-344 rat liver epithelial cells. The second assay evaluated the ability of the compounds to affect neutrophil function by measuring the production of superoxide in a human cell line (HL-60). Pyrene significantly blocked intercellular communication (f = 0.2-0.5) at 40 microM and complete inhibition of communication (f < 0.2) occurred at 50 microM. Gap junctional intercellular communication in cells exposed to biphenyl-2,2',6,6'-tetracarbaldehyde reached f < 0.5 at a concentration of 15 microM. At concentrations greater than 20 microM, biphenyl-2,2',6,6'-tetracarbaldehyde was cytotoxic and the inhibition of GJIC was caused by cell death. Biphenyl-2,2',6,6'-tetracarboxylic acid was neither cytotoxic nor inhibitory to GJIC at the concentrations tested (10-500 microM). Exposure to biphenyl-2,2',6,6'-tetracarbaldehyde resulted in a concentration-dependent decrease in phorbol 12-myristate 13-acetate-stimulated O2- production. Neither exposure to pyrene nor biphenyl-2,2',6,6'-tetracarboxylic acid caused a significant toxic effect on neutrophil function.
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Affiliation(s)
- Stephanie L Luster-Teasley
- Department of Civil and Environmental Engineering, Michigan State University, East Lansing, Michigan 48824, USA
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50
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Abstract
Polymethylhydrosiloxane (PMHS) made hypercoordinate by KF(aq) allows Me(3)SnH to be recycled during a Pd(0)-catalyzed hydrostannation/Stille cascade. Starting with a variety of alkynes, in situ vinyltin formation is followed by Stille reaction with aryl, styryl, benzyl, or vinyl electrophiles present in the reaction mixture. Both inter- and intramolecular versions of the process are possible with tin loads of approximately 6 mol %. Regeneration of the organotin hydride is believed to proceed through a Me(3)SnF intermediate. Given the aggregated nature of organotin fluorides and the ability to use these organotins in substoichiometric quantities, the hazards and purification problems associated with the removal of organotin wastes from reaction mixtures are minimized.
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Affiliation(s)
- William P Gallagher
- Department of Chemistry, Michigan State University, 540 Chemistry, East Lansing, MI 48824, USA
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