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Rorrer J, Pindi S, Toste FD, Bell AT. Effect of Alcohol Structure on the Kinetics of Etherification and Dehydration over Tungstated Zirconia. ChemSusChem 2018; 11:3104-3111. [PMID: 30044896 DOI: 10.1002/cssc.201801067] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/15/2018] [Indexed: 06/08/2023]
Abstract
Linear and branched ether molecules have attracted recent interest as diesel additives and lubricants that can be produced from biomass-derived alcohols. In this study, tungstated zirconia was identified as a selective and green solid acid catalyst for the direct etherification of primary alcohols in the liquid phase, achieving ether selectivities of >94 % for C6 -C12 linear alcohol coupling at 393 K. The length of linear primary alcohols (C6 -C12 ) was shown to have a negligible effect on apparent activation energies for etherification and dehydration, demonstrating the possibility to produce both symmetrical and asymmetrical linear ethers. Reactions over a series of C6 alcohols with varying methyl branch positions indicated that substituted alcohols (2°, 3°) and alcohols with branches on the β-carbon readily undergo dehydration, but alcohols with branches at least three carbons away from the -OH group are highly selective to ether. A novel model compound, 4-hexyl-1dodecanol, was synthesized and tested to further demonstrate this structure-activity relationship. Trends in the effects of alcohol structure on selectivity were consistent with previously proposed mechanisms for etherification and dehydration, and help to define possible pathways to selectively form ethers from biomass-derived alcohols.
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Affiliation(s)
- Julie Rorrer
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA
| | - Suresh Pindi
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - F Dean Toste
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Alexis T Bell
- Energy Biosciences Institute, University of California, Berkeley, CA, 94720, USA
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA
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Niemeyer ZL, Pindi S, Khrakovsky DA, Kuzniewski CN, Hong CM, Joyce LA, Sigman MS, Toste FD. Parameterization of Acyclic Diaminocarbene Ligands Applied to a Gold(I)-Catalyzed Enantioselective Tandem Rearrangement/Cyclization. J Am Chem Soc 2017; 139:12943-12946. [PMID: 28885017 PMCID: PMC5903265 DOI: 10.1021/jacs.7b08791] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [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: 11/28/2022]
Abstract
Computed descriptors for acyclic diaminocarbene ligands are developed in the context of a gold catalyzed enantioselective tandem [3,3]-sigmatropic rearrangement-[2+2]-cyclization. Surrogate structures enable the rapid identification of parameters that reveal mechanistic characteristics. The observed selectivity trends are validated in a robust multivariate analysis facilitating the development of a highly enantioselective process.
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Affiliation(s)
- Zachary L. Niemeyer
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Suresh Pindi
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Dimitri A. Khrakovsky
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Christian N. Kuzniewski
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Cynthia M. Hong
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Leo A. Joyce
- MRL, Department of Process Research & Development, Merck & Co., Inc., Rahway, New Jersey 07065, United States
| | - Matthew S. Sigman
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - F. Dean Toste
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
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Qiao S, Pindi S, Spigener PT, Jiang B, Li G. Asymmetric synthesis of homoallylic amines via 1,2-addition of Grignard reagent to aliphatic N-phosphonyl hemiaminal. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2015.12.106] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Seifert CW, Pindi S, Li G. Asymmetric Carbamoyl Anion Additions to Chiral N-Phosphonyl Imines via the GAP Chemistry Process and Stereoselectivity Enrichments. J Org Chem 2014; 80:447-52. [PMID: 25458404 PMCID: PMC4285137 DOI: 10.1021/jo5024443] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [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: 01/24/2023]
Abstract
Carbamoyl anions were found to smoothly react with chiral N-phosphonyl imines in toluene at -78 °C to r.t. using LiHMDS as the base. Group-assisted purification (GAP) has been utilized to give the pure amides without using column chromatography or recrystallization. The asymmetric reaction resulted in chiral N-phosphonyl amino amides with good to excellent yields (71-99%) and good crude diastereoselectivities (dr 84:16-95:5). In this GAP procedure, the crude solids are washed with diethyl ether to afford the pure products, as revealed by (1)H NMR analysis; GAP washing consistently increases the diastereopurity of the products, resulting in excellent diastereoselectivities, often with final dr > 99:1. Interestingly, the diastereoenriched products can be obtained either in the ether solution or as the suspended solid, depending on the substrate.
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Affiliation(s)
- Cole W Seifert
- †Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States
| | - Suresh Pindi
- †Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States
| | - Guigen Li
- †Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States
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Pindi S, Wu J, Li G. Design, synthesis, and applications of chiral N-2-phenyl-2-propyl sulfinyl imines for group-assisted purification (GAP) asymmetric synthesis. J Org Chem 2013; 78:4006-12. [PMID: 23496279 DOI: 10.1021/jo400354r] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A new chiral (Rs)-2-phenyl-2-propyl sulfinamide has been designed and synthesized; its derived aldimines and ketimines have been applied for asymmetric addition reaction with allylmagnesium bromide. The reaction was conveniently performed at room temperature to give a series of homoallylic amines in high yields (up to quant) and diastereoselectivity (up to >99% de). The pure products were obtained by relying on group-assisted purification (GAP) chemistry to avoid traditional purification methods of column chromatography or recrystallization. The conversion of disulfide to (R(s))-thiosulfinate which contains a newly generated polar group was also confirmed to be of the GAP chemistry in which washing crude product can generate pure enantiomer. The absolute stereochemistry has been determined by X-ray analysis.
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Affiliation(s)
- Suresh Pindi
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, USA
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Hu FL, Wei Y, Shi M, Pindi S, Li G. Asymmetric catalytic aza-Morita-Baylis-Hillman reaction for the synthesis of 3-substituted-3-aminooxindoles with chiral quaternary carbon centers. Org Biomol Chem 2013; 11:1921-4. [PMID: 23407608 DOI: 10.1039/c3ob27495k] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [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
The asymmetric catalytic aza-Morita-Baylis-Hillman (aza-MBH) reaction of isatin-derived ketimines with MVK has been established by using chiral amino and phosphino catalysts. The reaction resulted in biomedically important 3-substituted 3-amino-2-oxindoles in good yields (>80% for most cases) and with excellent enantioselectivity (90-99% ee). Twenty-eight cases assembled with chiral quaternary stereogenic centers have been examined under convenient systems.
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Affiliation(s)
- Fang-Le Hu
- Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, PR China
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Jiang B, Li QY, Zhang H, Tu SJ, Pindi S, Li G. Efficient domino approaches to multifunctionalized fused pyrroles and dibenzo[b,e][1,4]diazepin-1-ones. Org Lett 2012; 14:700-3. [PMID: 22260312 PMCID: PMC3676681 DOI: 10.1021/ol203166c] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Efficient domino approaches for the synthesis of multifunctionalized tricyclic fused pyrroles and dibenzo[b,e][1,4]diazepin-1-ones have been established. The reaction pathways were controlled by varying enaminones with different substituted patterns to give a series of new fused pyrroles and dibenzo[b,e][1,4]diazepin-1-ones selectively. The complete anti diastereoselectivity was achieved for the first reaction.
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Jiang B, Yi MS, Shi F, Tu SJ, Pindi S, McDowell P, Li G. A multi-component domino reaction for the direct access to polyfunctionalized indoles via intermolecular allylic esterification and indolation. Chem Commun (Camb) 2012; 48:808-10. [PMID: 22038299 PMCID: PMC3691686 DOI: 10.1039/c1cc15913e] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [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: 11/21/2022]
Abstract
A novel multi-component reaction for the synthesis of polyfunctionalized indoles and bis-indoles has been established. The reaction pathways were controlled by varying enamines with different substitution patterns to give polyfunctionalized indoles and bis-indoles selectively. The reaction proceeds at a fast speed within 15-30 min with water as the major byproduct, which makes work-up convenient.
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Affiliation(s)
- Bo Jiang
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Xuzhou Normal University, P. R. China
| | - Mian-Shuai Yi
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Xuzhou Normal University, P. R. China
| | - Feng Shi
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Xuzhou Normal University, P. R. China
| | - Shu-Jiang Tu
- School of Chemistry and Chemical Engineering, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Xuzhou Normal University, P. R. China
| | - Suresh Pindi
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Patrick McDowell
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Guigen Li
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
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Kattamuri PV, Ai T, Pindi S, Sun Y, Gu P, Shi M, Li G. Asymmetric synthesis of α-amino-1,3-dithianes via chiral N-phosphonyl imine-based Umpolung reaction without using chromatography and recrystallization. J Org Chem 2011; 76:2792-7. [PMID: 21405041 PMCID: PMC3074014 DOI: 10.1021/jo200070d] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [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] [Indexed: 01/07/2023]
Abstract
A series of α-amino-1,3-dithianes have been synthesized via the asymmetric Umpolung reaction of 2-lithio-1,3-dithianes with chiral N-phosphonyl imines in good chemical yields (up to 82%) and good to excellent diastereoselectivities (>99:1). The manner by which chiral N-phosphonyl imines are slowly added into the solution of 2-lithio-1,3-dithiane was found to be crucial for achieving excellent diastereoselectivity. The current synthesis was proven to follow the GAP chemistry (group-assistant-purification chemistry) process, which avoids traditional purification techniques of chromatography or recrystallization, i.e., the pure chiral α-amino-1,3-dithianes attached with the chiral N-phosphonyl group were readily obtained by washing the solid crude products with hexane or a mixture of hexane-ethyl acetate.
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Affiliation(s)
| | - Teng Ai
- Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Suresh Pindi
- Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Yinwei Sun
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, P. R. China
| | - Peng Gu
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, P. R. China
| | - Min Shi
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, P. R. China
| | - Guigen Li
- Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
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Pindi S, Kaur P, Shakya G, Li G. N-Phosphinyl Imine Chemistry (I): Design and Synthesis of Novel N-Phosphinyl Imines and their Application to Asymmetric aza-Henry Reaction. Chem Biol Drug Des 2010; 77:20-9. [DOI: 10.1111/j.1747-0285.2010.01047.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kaur P, Pindi S, Wever W, Rajale T, Li G. Asymmetric catalytic N-phosphonyl imine chemistry: the use of primary free amino acids and Et2AlCN for asymmetric catalytic Strecker reaction. J Org Chem 2010; 75:5144-50. [PMID: 20597482 PMCID: PMC2912979 DOI: 10.1021/jo100865q] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [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] [Indexed: 11/29/2022]
Abstract
The new asymmetric catalytic Strecker reaction of achiral N-phosphonyl imines has been established. Excellent enantioselectivity (95.2-99.7% ee) and yields (89-97%) have been achieved by using primary free natural amino acids as catalysts and Et(2)AlCN as nucleophile. This work also presents the novel use of nonvolatile and inexpensive Et(2)AlCN in asymmetric catalysis. The N-phosphonyl protecting group enabled simple product purification to be achieved simply by washing the crude products with hexane, which is defined as the GAP chemistry (GAP: Group-Assistant-Purification). It can also be readily cleaved and recycled under mild condition to give a quantitative recovery of N,N'-bis(naphthalen-1-ylmethyl)ethane-1,2-diamine. A new mechanism was proposed for this reaction and was supported by experimental observations.
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Affiliation(s)
- Parminder Kaur
- Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Suresh Pindi
- Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Walter Wever
- Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Trideep Rajale
- Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Guigen Li
- Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
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Kaur P, Pindi S, Wever W, Rajale T, Li G. Asymmetric catalytic Strecker reaction of N-phosphonyl imines with Et2AlCN using amino alcohols and BINOLs as catalysts. Chem Commun (Camb) 2010; 46:4330-2. [DOI: 10.1039/c0cc00287a] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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