1
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Soares NR, Huguet-Tapia JC, Guan D, Clark CA, Yang KT, Kluchka OR, Thombal RS, Kartika R, Badger JH, Pettis GS. Comparative genomics of the niche-specific plant pathogen Streptomyces ipomoeae reveal novel genome content and organization. Appl Environ Microbiol 2023; 89:e0030823. [PMID: 38009923 PMCID: PMC10734452 DOI: 10.1128/aem.00308-23] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 09/28/2023] [Indexed: 11/29/2023] Open
Abstract
IMPORTANCE While most plant-pathogenic Streptomyces species cause scab disease on a variety of plant hosts, Streptomyces ipomoeae is the sole causative agent of soil rot disease of sweet potato and closely related plant species. Here, genome sequencing of virulent and avirulent S. ipomoeae strains coupled with comparative genomic analyses has identified genome content and organization features unique to this streptomycete plant pathogen. The results here will enable future research into the mechanisms used by S. ipomoeae to cause disease and to persist in its niche environment.
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Affiliation(s)
- Natasha R. Soares
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | | | - Dongli Guan
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Christopher A. Clark
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
| | - Kuei-Ting Yang
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Olivia R. Kluchka
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Raju S. Thombal
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Rendy Kartika
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Jonathan H. Badger
- Laboratory of Integrative Cancer Immunology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Gregg S. Pettis
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, USA
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, USA
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2
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Badmus F, Thombal RS, Philkhana SC, Malone JA, Bailey CE, Armendariz-Gonzalez E, Mureka EW, Locicero CM, Fronczek FR, Kartika R. Directing the Stereoselectivity of the Claisen Rearrangement to Form Cyclic Ketones with Full Substitution at the α-Positions. Org Lett 2023; 25:7622-7627. [PMID: 37830497 PMCID: PMC10616857 DOI: 10.1021/acs.orglett.3c02752] [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: 08/22/2023] [Indexed: 10/14/2023]
Abstract
We report an enantioselective synthesis of cyclic ketones with full substitutions at the α-positions in a highly diastereoselective manner. Our method is achieved by subjecting substrate motifs in 2-allyloxyenones to chiral organomagnesium reagents, which trigger the Claisen rearrangement upon direct 1,2-carbonyl addition. The observed diastereoselectivity of the allyl migration is proposed to originate from the intramolecular chelation of the magnesium alkoxide to the allyloxy moiety.
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Affiliation(s)
- Fatimat
O. Badmus
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | | | | | - Joshua A. Malone
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | - Christian E. Bailey
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | | | - Edward W. Mureka
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | - Cale M. Locicero
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | - Frank R. Fronczek
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | - Rendy Kartika
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
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3
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Malone JA, Philkhana SC, Stepherson JR, Badmus FO, Fronczek FR, Kartika R. Copper(I)-Catalyzed Synthesis of Unsymmetrical All-Carbon Bis-Quaternary Centers at the Opposing α-Carbons of Cyclohexanones. Org Lett 2022; 24:4810-4815. [PMID: 35767696 PMCID: PMC9490817 DOI: 10.1021/acs.orglett.2c01890] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
![]()
We describe a new
synthetic reaction that generates all-carbon
bis-quaternary centers at the opposing side of α-carbons in
cyclohexanone with four different substituents in a controlled manner.
Catalyzed by Cu(MeCN)4BF4 salt, this chemistry
is proposed to proceed via an intermediacy of unsymmetrical O-allyl oxyallyl cations, which undergo a sequence of regioselective
nucleophilic addition with substituted indoles and diastereoselective
Claisen rearrangement in a single synthetic operation. The stereochemical
outcome of the products features the cis diastereorelationship
between the two aryl groups at the α,α′-positions.
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Affiliation(s)
- Joshua A Malone
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
| | - Satish Chandra Philkhana
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
| | - Jacob R Stepherson
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
| | - Fatimat O Badmus
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
| | - Frank R Fronczek
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
| | - Rendy Kartika
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
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4
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Abstract
This review article features selected examples on the synthesis of functionalized pyrroles that were reported between 2014 and 2019. Pyrrole is an important nitrogen-containing aromatic heterocycle that can be found in numerous compounds of biological and material significance. Given its vast importance, pyrrole continues to be an attractive target for the development of new synthetic reactions. The contents of this article are organized by the starting materials, which can be broadly classified into four different types: substrates bearing π-systems, substrates bearing carbonyl and other polar groups, and substrates bearing heterocyclic motifs. Brief discussions on plausible reaction mechanisms for most transformations are also presented.
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Affiliation(s)
- Satish Chandra Philkhana
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, LA 70803, USA
| | - Fatimat O Badmus
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, LA 70803, USA
| | - Isaac C Dos Reis
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, LA 70803, USA
| | - Rendy Kartika
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, LA 70803, USA
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5
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Abstract
This review article highlights selected advances in triphosgene-enabled organic synthetic reactions that were reported in the decade of 2010-2019. Triphosgene is a versatile reagent in organic synthesis. It serves as a convenient substitute for the toxic phosgene gas. Despite its first known preparation in the late 19th interestingly began only three decades ago. Despite the relatively short history, triphosgene has been proven to be very useful in facilitating the preparation of a vast scope of value-added compounds, such as organohalides, acid chlorides, isocyanates, carbonyl addition adducts, heterocycles, among others. Furthermore, applications of triphosgene in complex molecules synthesis, polymer synthesis, and other techniques, such as flow chemistry and solid phase synthesis, have also emerged in the literature.
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Affiliation(s)
| | | | | | - Rendy Kartika
- Department of Chemistry, 232 Choppin Hall, Louisiana State University, Baton Rouge, LA 70803 United States
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6
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Badmus FO, Malone JA, Fronczek FR, Kartika R. Synthesis of functionalized tetrahydropyrans via cascade cycloaddition involving silyloxyallyl cation intermediates. Chem Commun (Camb) 2020; 56:5034-5037. [DOI: 10.1039/d0cc01796e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
An expedient synthesis of highly substituted tetrahydrobenzofuran via an unsymmetrical silyloxyallyl cation is reported.
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Affiliation(s)
| | | | | | - Rendy Kartika
- Department of Chemistry
- Louisiana State University
- Baton Rouge
- USA
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7
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Badmus FO, Malone JA, Fronczek FR, Kartika R. Correction: Synthesis of functionalized tetrahydropyrans via cascade cycloaddition involving silyloxyallyl cation intermediates. Chem Commun (Camb) 2020; 56:6154. [DOI: 10.1039/d0cc90228d] [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: 11/21/2022]
Abstract
Correction for ‘Synthesis of functionalized tetrahydropyrans via cascade cycloaddition involving silyloxyallyl cation intermediates’ by Fatimat O. Badmus et al., Chem. Commun., 2020, 56, 5034–5037, DOI: 10.1039/D0CC01796E.
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Affiliation(s)
| | | | | | - Rendy Kartika
- Department of Chemistry
- Louisiana State University
- Baton Rouge
- USA
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8
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Abstract
The utility of triphosgene and DMAP as mild reagents for chemoselective dehydration of tertiary alcohols is reported. Performed in dichloromethane at room temperature, this reaction is readily tolerated by a broad scope of substrates, yielding alkenes preferentially with the (E)-geometry. While formation of the Hofmann products is generally favored, a dramatic change in alkene selectivity toward the Zaitzev products is observed when the reaction is carried out in dichloroethane at reflux.
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Affiliation(s)
- Moshood O Ganiu
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Alexander H Cleveland
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Jarrod L Paul
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Rendy Kartika
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
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9
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Bresnahan CG, Taylor-Edinbyrd KA, Cleveland AH, Malone JA, Dange NS, Milet A, Kumar R, Kartika R. Mechanistic Perspectives in the Regioselective Indole Addition to Unsymmetrical Silyloxyallyl Cations. J Org Chem 2019; 84:7166-7174. [PMID: 31050428 DOI: 10.1021/acs.joc.9b00853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [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
Our investigations on the reaction mechanism to account for regioselectivity on the addition of indoles to unsymmetrical silyloxyallyl cations are reported. Using both experimental and computational methods, we confirmed the significance of steric effects from the silyl ether group toward directing the inward approach of indoles, leading to nucleophilic attack at the less substituted electrophilic α'-carbon. The role of residual water toward accelerating the rate of reaction is established through stabilization of the participating silyloxyallyl cation.
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Affiliation(s)
- Caitlin G Bresnahan
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Kiara A Taylor-Edinbyrd
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Alexander H Cleveland
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Joshua A Malone
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Nitin S Dange
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Anne Milet
- Département de Chimie Moléculaire, Université Grenoble Alpes, CNRS, UMR 5250 , F-38000 Grenoble , France
| | - Revati Kumar
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Rendy Kartika
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
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10
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Malone JA, Toussel CE, Fronczek FR, Kartika R. Brønsted Acid-Catalyzed Formal [2 + 2 + 1] Annulation for the Modular Synthesis of Tetrahydroindoles and Tetrahydrocyclopenta[ b]pyrroles. Org Lett 2019; 21:3610-3614. [PMID: 31033299 PMCID: PMC7055494 DOI: 10.1021/acs.orglett.9b01032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [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: 11/30/2022]
Abstract
An expedient synthesis of tetrahydroindoles and tetrahydrocyclopenta[ b]pyrroles, highlighted by Brønsted acid catalyzed formal [2 + 2 + 1] annulation reaction, is reported. Using three readily accessible reaction components, i.e., an electrophilic species in silyloxyallyl cations and two distinct nucleophiles in silylenol ethers and amines, our chemistry enables the assembly and functionalization of these biologically important N-heterocycles in a highly modular manner.
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Affiliation(s)
- Joshua A. Malone
- Department of Chemistry, 232 Choppin Hall, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Courtney E. Toussel
- Department of Chemistry, 232 Choppin Hall, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Frank R. Fronczek
- Department of Chemistry, 232 Choppin Hall, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Rendy Kartika
- Department of Chemistry, 232 Choppin Hall, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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11
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Saputra MA, Nepal B, Dange NS, Du P, Fronczek FR, Kumar R, Kartika R. Enantioselective Functionalization of Enamides at the β-Carbon Center with Indoles. Angew Chem Int Ed Engl 2018; 57:15558-15562. [PMID: 30191642 PMCID: PMC6407611 DOI: 10.1002/anie.201808764] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/27/2018] [Indexed: 11/05/2022]
Abstract
We report an enantioconvergent approach for the functionalization of enamides at the β-carbon atom, which involves a chiral Brønsted acid induced tautomerization of 2-amidoallyl into 1-amidoallyl cations. These putative reactive intermediates were produced by ionization of racemic α-hydroxy enamides with a chiral Brønsted acid and captured with substituted indoles in a highly regio- and enantioselective manner.
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Affiliation(s)
- Mirza A. Saputra
- Department of Chemistry, Louisiana State University 232 Choppin Hall, Baton Rouge, LA 70803 (USA)
| | - Binod Nepal
- Department of Chemistry, Louisiana State University 232 Choppin Hall, Baton Rouge, LA 70803 (USA)
| | - Nitin S. Dange
- Department of Chemistry, Louisiana State University 232 Choppin Hall, Baton Rouge, LA 70803 (USA)
| | - Pu Du
- Department of Chemistry, Louisiana State University 232 Choppin Hall, Baton Rouge, LA 70803 (USA)
| | - Frank R. Fronczek
- Department of Chemistry, Louisiana State University 232 Choppin Hall, Baton Rouge, LA 70803 (USA)
| | - Revati Kumar
- Department of Chemistry, Louisiana State University 232 Choppin Hall, Baton Rouge, LA 70803 (USA)
| | - Rendy Kartika
- Department of Chemistry, Louisiana State University 232 Choppin Hall, Baton Rouge, LA 70803 (USA)
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12
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Saputra MA, Nepal B, Dange NS, Du P, Fronczek FR, Kumar R, Kartika R. Enantioselective Functionalization of Enamides at the β‐Carbon Center with Indoles. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201808764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Mirza A. Saputra
- Department of ChemistryLouisiana State University 232 Choppin Hall Baton Rouge LA 70803 USA
| | - Binod Nepal
- Department of ChemistryLouisiana State University 232 Choppin Hall Baton Rouge LA 70803 USA
| | - Nitin S. Dange
- Department of ChemistryLouisiana State University 232 Choppin Hall Baton Rouge LA 70803 USA
| | - Pu Du
- Department of ChemistryLouisiana State University 232 Choppin Hall Baton Rouge LA 70803 USA
| | - Frank R. Fronczek
- Department of ChemistryLouisiana State University 232 Choppin Hall Baton Rouge LA 70803 USA
| | - Revati Kumar
- Department of ChemistryLouisiana State University 232 Choppin Hall Baton Rouge LA 70803 USA
| | - Rendy Kartika
- Department of ChemistryLouisiana State University 232 Choppin Hall Baton Rouge LA 70803 USA
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13
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Cleveland AH, Fronczek FR, Kartika R. Synthesis of Vicinal Dichlorides via Activation of Aliphatic Terminal Epoxides with Triphosgene and Pyridine. J Org Chem 2018; 83:3367-3377. [PMID: 29465239 DOI: 10.1021/acs.joc.7b03197] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Herein we report a novel synthetic reaction to convert unactivated terminal aliphatic epoxide to alkyl vicinal dichloride based on triphosgene-pyridine activation. Our methodology is operationally simple and readily tolerated by a broad of scope of substrates as well as protecting groups. Furthermore, these mild conditions generally yield clean reaction mixtures that are free of byproducts upon aqueous workup.
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Affiliation(s)
- Alexander H Cleveland
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Frank R Fronczek
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
| | - Rendy Kartika
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , Louisiana 70803 , United States
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14
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Malone JA, Van Houten JP, Ganiu MO, Nepal B, Kartika R. Brønsted Acid Catalyzed Synthesis of Functionalized 1,4- and 1,6-Dicarbonyl Monosilyl Enol Ethers under Operationally Practical Conditions. J Org Chem 2017; 82:10659-10664. [PMID: 28849920 DOI: 10.1021/acs.joc.7b01687] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [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
Herein, we report an improved protocol for the concise synthesis of functionalized 1,4- and 1,6-dicarbonyl-derived monosilyl enol ethers via ionization of α'-hydroxy silyl enol ethers to generate unsymmetrical silyloxyallyl cations that were subsequently captured by TBS silyl enolates. These transformations were efficiently performed in acetonitrile at room temperature by employing pyridinium triflate as a catalyst. Our new reaction conditions are operationally more practical and broaden the accessibility of various 1,4- and 1,6-dicarbonyl groups, which include diketone, ketoester, and ketothioester functionalities.
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Affiliation(s)
- Joshua A Malone
- Department of Chemistry 232 Choppin Hall Louisiana State University Baton Rouge, Louisiana 70803, United States
| | - Joshua P Van Houten
- Department of Chemistry 232 Choppin Hall Louisiana State University Baton Rouge, Louisiana 70803, United States
| | - Moshood O Ganiu
- Department of Chemistry 232 Choppin Hall Louisiana State University Baton Rouge, Louisiana 70803, United States
| | - Binod Nepal
- Department of Chemistry 232 Choppin Hall Louisiana State University Baton Rouge, Louisiana 70803, United States
| | - Rendy Kartika
- Department of Chemistry 232 Choppin Hall Louisiana State University Baton Rouge, Louisiana 70803, United States
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15
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Saputra MA, Dange NS, Cleveland AH, Malone JA, Fronczek FR, Kartika R. Regioselective Functionalization of Enamides at the α-Carbon via Unsymmetrical 2-Amidoallyl Cations. Org Lett 2017; 19:2414-2417. [DOI: 10.1021/acs.orglett.7b00962] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mirza A. Saputra
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | - Nitin S. Dange
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | - Alexander H. Cleveland
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | - Joshua A. Malone
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | - Frank R. Fronczek
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
| | - Rendy Kartika
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton
Rouge, Louisiana 70803, United States
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16
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Malone JA, Cleveland AH, Fronczek FR, Kartika R. Effects of Solvent and Residual Water on Enhancing the Reactivity of Six-Membered Silyloxyallyl Cations toward Nucleophilic Addition. Org Lett 2016; 18:4408-11. [DOI: 10.1021/acs.orglett.6b02194] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [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)
- Joshua A. Malone
- Department of Chemistry, 232 Choppin Hall, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
| | - Alexander H. Cleveland
- Department of Chemistry, 232 Choppin Hall, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
| | - Frank R. Fronczek
- Department of Chemistry, 232 Choppin Hall, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
| | - Rendy Kartika
- Department of Chemistry, 232 Choppin Hall, Louisiana State University, Baton
Rouge, Louisiana 70803, United States
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17
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Villalpando A, Saputra MA, Tugwell TH, Kartika R. Triphosgene-pyridine mediated stereoselective chlorination of acyclic aliphatic 1,3-diols. Chem Commun (Camb) 2016; 51:15075-8. [PMID: 26323232 DOI: 10.1039/c5cc06365e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We describe a strategy to chlorinate stereocomplementary acyclic aliphatic 1,3-diols using a mixture of triphosgene and pyridine. While 1,3-anti diols readily led to 1,3-anti dichlorides, 1,3-syn diols must be converted to 1,3-syn diol monosilylethers to access the corresponding 1,3-syn dichlorides. These dichlorination protocols were operationally simple, very mild, and readily tolerated by advanced synthetic intermediates.
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Affiliation(s)
- Andrés Villalpando
- Department of Chemistry, 232 Choppin Hall, Louisiana State University, Baton Rouge, LA 70803, USA.
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18
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Stepherson JR, Ayala CE, Tugwell TH, Henry JL, Fronczek FR, Kartika R. Carbazole Annulation via Cascade Nucleophilic Addition–Cyclization Involving 2-(Silyloxy)pentadienyl Cation. Org Lett 2016; 18:3002-5. [DOI: 10.1021/acs.orglett.6b01376] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jacob R. Stepherson
- Department
of Chemistry, 232 Choppin
Hall, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Caitlan E. Ayala
- Department
of Chemistry, 232 Choppin
Hall, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Thomas H. Tugwell
- Department
of Chemistry, 232 Choppin
Hall, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Jeffrey L. Henry
- Department
of Chemistry, 232 Choppin
Hall, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Frank R. Fronczek
- Department
of Chemistry, 232 Choppin
Hall, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Rendy Kartika
- Department
of Chemistry, 232 Choppin
Hall, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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19
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Ayala CE, Dange NS, Stepherson JR, Henry JL, Fronczek FR, Kartika R. Functionalization of Silyldienol Ethers at the γ-Position via 2-Silyloxypentadienyl Cations. Org Lett 2016; 18:1084-7. [PMID: 26867094 DOI: 10.1021/acs.orglett.6b00196] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This report describes Brønsted acid catalyzed de novo synthesis of silyldienol ethers bearing tetrasubstituted double bonds via an intermediacy of 2-silyloxypentadienyl cations. The reactivity of these novel cationic intermediates could be modulated and harnessed toward direct nucleophilic additions regioselectively at the γ-position to produce highly functionalized silyldienol ethers with tunable control of the resulting double bond geometry.
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Affiliation(s)
- Caitlan E Ayala
- Department of Chemistry, Louisiana State University , 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
| | - Nitin S Dange
- Department of Chemistry, Louisiana State University , 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
| | - Jacob R Stepherson
- Department of Chemistry, Louisiana State University , 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
| | - Jeffrey L Henry
- Department of Chemistry, Louisiana State University , 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
| | - Frank R Fronczek
- Department of Chemistry, Louisiana State University , 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
| | - Rendy Kartika
- Department of Chemistry, Louisiana State University , 232 Choppin Hall, Baton Rouge, Louisiana 70803, United States
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Vastl J, Kartika R, Park K, Cho AE, Spiegel DA. Peptidines: glycine-amidine-based oligomers for solution- and solid-phase synthesis. Chem Sci 2016; 7:3317-3324. [PMID: 29997824 PMCID: PMC6006957 DOI: 10.1039/c5sc03882k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/31/2016] [Indexed: 12/17/2022] Open
Abstract
Efforts to emulate biological oligomers have given rise to a host of useful technologies, ranging from solid-phase peptide and nucleic acid synthesis to various peptidomimetic platforms. Herein we introduce a novel class of peptide-like oligomers called "peptidines" wherein each carbonyl O-atom within poly-N-alkyl glycine oligomers is replaced with a functionalized N-atom. Compared to peptoids or peptides, the presence of this amidine N-substituent in peptidines effectively doubles the number of diversification sites per monomeric unit, and can decrease their overall conformational flexibility. We have developed iterative solution- and solid-phase protocols for the straightforward assembly of peptidines containing diverse backbone and amidine substituents, derived from readily available primary and secondary amines. We have also performed crystallographic and computational studies, which demonstrate a strong preference for the trans (E) amidine geometry. Given their straightforward synthetic preparation and high functional group density, peptidines have the potential to serve as useful tools for library generation, peptide mimicry, and the identification of biologically active small molecules.
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Affiliation(s)
- Julian Vastl
- Department of Chemistry , Yale University , 225 Prospect Street , New Haven , CT 06511 , USA .
| | - Rendy Kartika
- Department of Chemistry , Louisinanna State University , 337 Chemistry and Materials Building , Baton Rouge , LA 70803 , USA
| | - Kichul Park
- Department of Bioinformatics , Korea University Sejong Campus , 2511 Sejong-ro , Sejong City 399-770 , Korea
| | - Art E Cho
- Department of Bioinformatics , Korea University Sejong Campus , 2511 Sejong-ro , Sejong City 399-770 , Korea
| | - David A Spiegel
- Department of Chemistry , Yale University , 225 Prospect Street , New Haven , CT 06511 , USA . .,Department of Pharmacology , Yale University , 333 Cedar Street , New Haven , CT 06520 , USA
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Stepherson JR, Fronczek FR, Kartika R. An expedient synthesis of functionalized 1,4-diketone-derived compounds via silyloxyallyl cation intermediates. Chem Commun (Camb) 2016; 52:2300-3. [DOI: 10.1039/c5cc09763k] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Herein we describe the synthesis of highly functionalized 1,4-diketones that are readily differentiated as monosilylenol ethers via direct capture of silyloxyallyl cations by silyl enolates under Brønsted acid catalysis.
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Affiliation(s)
- Jacob R. Stepherson
- Department of Chemistry
- 232 Choppin Hall
- Louisiana State University
- Baton Rouge
- USA
| | - Frank R. Fronczek
- Department of Chemistry
- 232 Choppin Hall
- Louisiana State University
- Baton Rouge
- USA
| | - Rendy Kartika
- Department of Chemistry
- 232 Choppin Hall
- Louisiana State University
- Baton Rouge
- USA
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Kartika R, Stepherson J, Ayala C, Dange N. Nucleophilic Capture of Unsymmetrical Oxyallyl Cations with Indoles under Mild Brønsted Acid Catalysis. Synlett 2015. [DOI: 10.1055/s-0035-1560801] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Dange NS, Stepherson JR, Ayala CE, Fronczek FR, Kartika R. Cooperative benzylic-oxyallylic stabilized cations: regioselective construction of α-quaternary centers in ketone-derived compounds. Chem Sci 2015; 6:6312-6319. [PMID: 30090249 PMCID: PMC6054113 DOI: 10.1039/c5sc01914a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 07/20/2015] [Indexed: 11/23/2022] Open
Abstract
We describe a novel reactivity of benzylic-stabilized oxyallyl cations towards regioselective construction of carbon quaternary centers. These synthetically useful intermediates were readily generated upon ionization of aryl substituted α-hydroxy methylenol ethers with catalytic, mild Brønsted acid. The emerging unsymmetrical oxyallyl cations were then directly captured by indoles and other nucleophiles with exquisite control of regioselectivity, predictably at the electrophilic carbon bearing the alkyl substituent to produce highly functionalized, value-added enol ethers.
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Affiliation(s)
- Nitin S Dange
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , LA 70810 , USA .
| | - Jacob R Stepherson
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , LA 70810 , USA .
| | - Caitlan E Ayala
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , LA 70810 , USA .
| | - Frank R Fronczek
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , LA 70810 , USA .
| | - Rendy Kartika
- Department of Chemistry , Louisiana State University , 232 Choppin Hall , Baton Rouge , LA 70810 , USA .
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Affiliation(s)
- Mirza A. Saputra
- Department of Chemistry, Louisiana State University, 232 Choppin
Hall, Baton
Rouge, Louisiana 70803, United States
| | - Ly Ngo
- Department of Chemistry, Louisiana State University, 232 Choppin
Hall, Baton
Rouge, Louisiana 70803, United States
| | - Rendy Kartika
- Department of Chemistry, Louisiana State University, 232 Choppin
Hall, Baton
Rouge, Louisiana 70803, United States
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Ayala CE, Dange NS, Fronczek FR, Kartika R. Brønsted Acid Catalyzed α′-Functionalization of Silylenol Ethers with Indoles. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201409758] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Ayala CE, Dange NS, Fronczek FR, Kartika R. Brønsted Acid Catalyzed α′-Functionalization of Silylenol Ethers with Indoles. Angew Chem Int Ed Engl 2015; 54:4641-5. [DOI: 10.1002/anie.201409758] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 01/21/2015] [Indexed: 11/10/2022]
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Abstract
Unactivated α-branched primary and secondary aliphatic alcohols have been successfully transformed into their corresponding alkyl chlorides in high yields upon treatment with a mixture of triphosgene and pyridine in dichloromethane at reflux. These mild chlorination conditions are high yielding, stereospecific, and well tolerated by numerous sensitive functionalities. Furthermore, no nuisance waste products are generated in the course of the reactions.
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Affiliation(s)
- Andrés Villalpando
- Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, Louisiana 70803, USA
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Ayala CE, Villalpando A, Nguyen AL, McCandless GT, Kartika R. Chlorination of aliphatic primary alcohols via triphosgene-triethylamine activation. Org Lett 2012; 14:3676-9. [PMID: 22780451 DOI: 10.1021/ol301520d] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Activation of primary aliphatic alcohols with triphosgene and triethylamine mixtures afforded either alkyl chloride or diethylcarbamate products, and the switch in selectivity appeared to be driven by sterics. The reaction conditions to achieve this highly useful transformation were unexceptionally mild and readily tolerated by a wide range of sensitive functionalities.
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Affiliation(s)
- Caitlan E Ayala
- Department of Chemistry, 232 Choppin Hall, Louisiana State University , Baton Rouge, Louisiana 70803, United States
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Wang T, Kartika R, Spiegel DA. Exploring post-translational arginine modification using chemically synthesized methylglyoxal hydroimidazolones. J Am Chem Soc 2012; 134:8958-67. [PMID: 22591136 PMCID: PMC3397831 DOI: 10.1021/ja301994d] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [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: 01/09/2023]
Abstract
The methylglyoxal-derived hydroimidazolones (MG-Hs) comprise the most prevalent class of non-enzymatic, post-translational modifications of protein arginine residues found in nature. These adducts form spontaneously in the human body, and are also present at high levels in the human diet. Despite numerous lines of evidence suggesting that MG-H-arginine adducts play critical roles in both healthy and disease physiology in humans, detailed studies of these molecules have been hindered by a lack of general synthetic strategies for their preparation in chemically homogeneous form, and on scales sufficient to enable detailed biochemical and cellular investigations. To address this limitation, we have developed efficient, multigram-scale syntheses of all MG-H-amino acid building blocks, suitably protected for solid-phase peptide synthesis, in 2-3 steps starting from inexpensive, readily available starting materials. Thus, MG-H derivatives were readily incorporated into oligopeptides site-specifically using standard solid-phase peptide synthesis. Access to synthetic MG-H-peptide adducts has enabled detailed investigations, which have revealed a series of novel and unexpected findings. First, one of the three MG-H isomers, MG-H3, was found to possess potent, pH-dependent antioxidant properties in biochemical and cellular assays intended to replicate redox processes that occur in vivo. Computational and mechanistic studies suggest that MG-H3-containing constructs are capable of participating in mechanistically distinct H-atom-transfer and single-electron-transfer oxidation processes. Notably, the product of MG-H3 oxidation was unexpectedly observed to disassemble into the fully unmodified arginine residue and pyruvate in aqueous solution. We believe these observations provide insight into the role(s) of MG-H-protein adducts in human physiology, and expect the synthetic reagents reported herein to enable investigations into non-enzymatic protein regulation at an unprecedented level of detail.
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Affiliation(s)
- Tina Wang
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511, USA
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Abstract
A concise total synthesis of neopeltolide macrolactone has been accomplished in 14 steps in the longest linear sequence, 15 steps overall from commercially available materials. The present synthesis was highlighted by successful exploitation of ether transfer methodology and a radical cyclization reaction to directly establish the requisite stereochemistry of the tetrahydropyran core.
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Affiliation(s)
- Rendy Kartika
- Department of Chemistry and Biochemistry and the Walther Cancer Research Center, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556-5670, USA
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Kartika R, Frein JD, Taylor RE. Electrophile-Induced Ether Transfer: Stereoselective Synthesis of 2,6-Disubstituted-3,4-Dihydropyrans. J Org Chem 2008; 73:5592-4. [DOI: 10.1021/jo800704d] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rendy Kartika
- Department of Chemistry and Biochemistry and the Walther Cancer Research Center, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556
| | - Jeffrey D. Frein
- Department of Chemistry and Biochemistry and the Walther Cancer Research Center, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556
| | - Richard E. Taylor
- Department of Chemistry and Biochemistry and the Walther Cancer Research Center, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556
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Abstract
The hydroxyalkylation reactions of aceanthrenequinone (6) and acenapthenequinone (7) with a series of arenes have been studied. In reactions with the Brønsted superacid CF(3)SO(3)H (triflic acid), the condensation products are formed in good yields (58-99%, 10 examples) with high regioselectivity. Computational studies were also done to examine the structures and energies of mono- and diprotonated species from 6 and 7. The results from the condensation reactions are consistent with the formation of superelectrophilic species involving protosolvation of carboxonium ion intermediates.
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Affiliation(s)
- Douglas A. Klumpp
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois, 60115
| | - Yiliang Zhang
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois, 60115
| | - Dat Do
- Department of Chemistry, California State Polytechnic University, Pomona, California, 90178
| | - Rendy Kartika
- Department of Chemistry, California State Polytechnic University, Pomona, California, 90178
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Affiliation(s)
- Rendy Kartika
- Department of Chemistry and Biochemistry and the Walther Cancer Research Center, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556-5670, USA
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Kartika R, Taylor R. Electrophile-Induced Ether Transfer: Stereoselective Synthesis of 2,4,6-Trisubstituted Tetrahydropyrans. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200702018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
[Structure: see text] A strategically novel approach to the formation of syn-1,3-diol mono- and diethers through electrophilic activation of homoallylic alkoxymethyl ethers has been developed. The resulting polyketide-like synthetic fragments are generated in good yield and with excellent stereocontrol. A chairlike transition state is proposed to account for the high stereoselectivity. Varying the conditions of the reaction workup results in the efficient generation of mono- and diether containing structural units common to polyketide natural products.
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Affiliation(s)
- Kai Liu
- Department of Chemistry and Biochemistry and the Walther Cancer Research Center, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556-5670, USA
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