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Kim SW, Meyer CC, Mai BK, Liu P, Krische MJ. Inversion of Enantioselectivity in Allene Gas versus Allyl Acetate Reductive Aldehyde Allylation Guided by Metal-Centered Stereogenicity: An Experimental and Computational Study. ACS Catal 2019; 9:9158-9163. [PMID: 31857913 DOI: 10.1021/acscatal.9b03695] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The use of gaseous allene as an allyl pronucleophile in enantioselective aldehyde reductive coupling is described. Notably, using the same antipode of chiral ligand, (S)-tol-BINAP, an inversion of enantioselectivity is observed for allene vs allyl acetate pronucleophiles. Experimental and computational studies corroborate intervention of diastereomeric π-allyliridium-C,O-benzoate complexes, which arise via allene hydrometalation (from a pentacoordinate iridium hydride) vs allyl acetate ionization (from a square planar iridium species).
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Affiliation(s)
- Seung Wook Kim
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Cole C. Meyer
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Binh Khanh Mai
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Michael J. Krische
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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2
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Cabrera JM, Tauber J, Zhang W, Xiang M, Krische MJ. Selection between Diastereomeric Kinetic vs Thermodynamic Carbonyl Binding Modes Enables Enantioselective Iridium-Catalyzed anti-(α-Aryl)allylation of Aqueous Fluoral Hydrate and Difluoroacetaldehyde Ethyl Hemiacetal. J Am Chem Soc 2018; 140:9392-9395. [PMID: 30020777 PMCID: PMC6206506 DOI: 10.1021/jacs.8b05725] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enantioselectivity increases with increasing carbonyl electrophilicity in 2-propanol-mediated reductive couplings of aldehydes with branched aryl-substituted allylic acetates to form products of carbonyl anti-(α-aryl)allylation. This unusual phenomenon is caused by aldehyde coordination to diastereomeric kinetic vs thermodynamic carbonyl binding sites that deliver enantiomeric products. Exploiting this effect, anti-diastereo- and enantioselective (α-aryl)allylations of fluoral hydrate and difluoroacetaldehyde ethyl hemiacetal were developed.
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Affiliation(s)
- James M Cabrera
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Johannes Tauber
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Wandi Zhang
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Ming Xiang
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Michael J Krische
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
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Brito GA, Della-Felice F, Luo G, Burns AS, Pilli RA, Rychnovsky SD, Krische MJ. Catalytic Enantioselective Allylations of Acetylenic Aldehydes via 2-Propanol-Mediated Reductive Coupling. Org Lett 2018; 20:4144-4147. [PMID: 29938513 PMCID: PMC6205292 DOI: 10.1021/acs.orglett.8b01776] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyclometalated π-allyliridium C,O-benzoates modified by ( S)-SEGPHOS or ( S)-Cl,OMe-BIPHEP catalyze enantioselective 2-propanol-mediated reductive couplings of diverse nonmetallic allyl pronucleophiles with the acetylenic aldehyde TIPSC≡CCHO. Absolute stereochemistries of the resulting secondary homoallylic-propargylic alcohols were assigned using Rychnovsky's competing enantioselective conversion method.
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Affiliation(s)
- Gilmar A Brito
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
- Institute of Chemistry, University of Campinas (UNICAMP) , P.O. Box 6154, CEP, 13083-970 Campinas , São Paulo , Brazil
| | - Franco Della-Felice
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
- Institute of Chemistry, University of Campinas (UNICAMP) , P.O. Box 6154, CEP, 13083-970 Campinas , São Paulo , Brazil
| | - Guoshun Luo
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Alexander S Burns
- Department of Chemistry , University of California at Irvine , 1102 Natural Sciences II , Irvine , California 92697 , United States
| | - Ronaldo A Pilli
- Institute of Chemistry, University of Campinas (UNICAMP) , P.O. Box 6154, CEP, 13083-970 Campinas , São Paulo , Brazil
| | - Scott D Rychnovsky
- Department of Chemistry , University of California at Irvine , 1102 Natural Sciences II , Irvine , California 92697 , United States
| | - Michael J Krische
- Department of Chemistry , University of Texas at Austin , Austin , Texas 78712 , United States
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Holmes M, Schwartz LA, Krische MJ. Intermolecular Metal-Catalyzed Reductive Coupling of Dienes, Allenes, and Enynes with Carbonyl Compounds and Imines. Chem Rev 2018; 118:6026-6052. [PMID: 29897740 DOI: 10.1021/acs.chemrev.8b00213] [Citation(s) in RCA: 405] [Impact Index Per Article: 67.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Metal-catalyzed reductive coupling has emerged as an alternative to the use of stoichiometric organometallic reagents in an increasingly diverse range of carbonyl and imine additions. In this review, the use of diene, allene, and enyne pronucleophiles in intermolecular carbonyl and imine reductive couplings are surveyed, along with related hydrogen autotransfer processes.
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Affiliation(s)
- Michael Holmes
- Department of Chemistry , University of Texas at Austin , Welch Hall A5300, 105 East 24th Street , Austin , Texas 78712 , United States
| | - Leyah A Schwartz
- Department of Chemistry , University of Texas at Austin , Welch Hall A5300, 105 East 24th Street , Austin , Texas 78712 , United States
| | - Michael J Krische
- Department of Chemistry , University of Texas at Austin , Welch Hall A5300, 105 East 24th Street , Austin , Texas 78712 , United States
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Feng J, Kasun ZA, Krische MJ. Enantioselective Alcohol C-H Functionalization for Polyketide Construction: Unlocking Redox-Economy and Site-Selectivity for Ideal Chemical Synthesis. J Am Chem Soc 2016; 138:5467-78. [PMID: 27113543 PMCID: PMC4871165 DOI: 10.1021/jacs.6b02019] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The development and application of stereoselective and site-selective catalytic methods that directly convert lower alcohols to higher alcohols are described. These processes merge the characteristics of transfer hydrogenation and carbonyl addition, exploiting alcohols and π-unsaturated reactants as redox pairs, which upon hydrogen transfer generate transient carbonyl-organometal pairs en route to products of C-C coupling. Unlike classical carbonyl additions, stoichiometric organometallic reagents and discrete alcohol-to-carbonyl redox reactions are not required. Additionally, due to a kinetic preference for primary alcohol dehydrogenation, the site-selective modification of glycols and higher polyols is possible, streamlining or eliminating use of protecting groups. The total syntheses of several iconic type I polyketide natural products were undertaken using these methods. In each case, the target compounds were prepared in significantly fewer steps than previously achieved.
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Affiliation(s)
- Jiajie Feng
- University of Texas at Austin, Department of Chemistry, Austin, TX 78712, USA
| | - Zachary A. Kasun
- University of Texas at Austin, Department of Chemistry, Austin, TX 78712, USA
| | - Michael J. Krische
- University of Texas at Austin, Department of Chemistry, Austin, TX 78712, USA
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Ketcham JM, Shin I, Montgomery TP, Krische MJ. Catalytic enantioselective C-H functionalization of alcohols by redox-triggered carbonyl addition: borrowing hydrogen, returning carbon. Angew Chem Int Ed Engl 2014; 53:9142-50. [PMID: 25056771 PMCID: PMC4150357 DOI: 10.1002/anie.201403873] [Citation(s) in RCA: 272] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Indexed: 12/12/2022]
Abstract
The use of alcohols and unsaturated reactants for the redox-triggered generation of nucleophile-electrophile pairs represents a broad, new approach to carbonyl addition chemistry. Discrete redox manipulations that are often required for the generation of carbonyl electrophiles and premetalated carbon-centered nucleophiles are thus avoided. Based on this concept, a broad, new family of enantioselective C-C coupling reactions that are catalyzed by iridium or ruthenium complexes have been developed, which are summarized in this Minireview.
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Affiliation(s)
- John M Ketcham
- University of Texas at Austin, Department of Chemistry and Biochemistry, 1 University Station - A5300, Austin, TX 78712-1167 (USA)
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Ketcham JM, Shin I, Montgomery TP, Krische MJ. Katalytische enantioselektive C-H-Funktionalisierung von Alkoholen durch redoxgesteuerte Addition an die Carbonylgruppe: Wasserstoff-Ausleihe und Kohlenstoff-Rückgabe. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201403873] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Dechert-Schmitt AMR, Schmitt DC, Gao X, Itoh T, Krische MJ. Polyketide construction via hydrohydroxyalkylation and related alcohol C-H functionalizations: reinventing the chemistry of carbonyl addition. Nat Prod Rep 2014; 31:504-13. [PMID: 24514754 PMCID: PMC3954971 DOI: 10.1039/c3np70076c] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Despite the longstanding importance of polyketide natural products in human medicine, nearly all commercial polyketide-based drugs are prepared through fermentation or semi-synthesis. The paucity of manufacturing routes involving de novo chemical synthesis reflects the inability of current methods to concisely address the preparation of these complex structures. Direct alcohol C-H bond functionalization via"C-C bond forming transfer hydrogenation" provides a powerful, new means of constructing type I polyketides that bypasses stoichiometric use of chiral auxiliaries, premetallated C-nucleophiles, and discrete alcohol-to-aldehyde redox reactions. Using this emergent technology, total syntheses of 6-deoxyerythronolide B, bryostatin 7, trienomycins A and F, cyanolide A, roxaticin, and formal syntheses of rifamycin S and scytophycin C, were accomplished. These syntheses represent the most concise routes reported to any member of the respective natural product families.
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Affiliation(s)
- Anne-Marie R Dechert-Schmitt
- University of Texas at Austin, Department of Chemistry and Biochemistry, 105 E 24th St., Welch Hall A5300, Austin, TX 78712-1165, USA.
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Kretschmer M, Dieckmann M, Li P, Rudolph S, Herkommer D, Troendlin J, Menche D. Modular Total Synthesis of Rhizopodin: A Highly Potent G-Actin Dimerizing Macrolide. Chemistry 2013; 19:15993-6018. [DOI: 10.1002/chem.201302197] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Indexed: 01/13/2023]
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Kretschmer M, Menche D. Stereocontrolled synthesis of the C8-C22 fragment of rhizopodin. Org Lett 2011; 14:382-5. [PMID: 22149453 DOI: 10.1021/ol203130b] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A convergent synthesis of the central C8-C22 core of the potent macrolide antibiotic rhizopodin is reported. Notable features of the stereocontrolled approach include an asymmetric reverse prenylation of an alcohol using a method of Krische, a thiazolium catalyzed transformation of an epoxyaldehyde as described by Bode, and a late-stage oxazole formation from advanced intermediates. This route demonstrates the applicability of these methodologies in complex natural product synthesis.
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Affiliation(s)
- Manuel Kretschmer
- Universität Heidelberg, Institut für Organische Chemie, INF 270, D-69120 Heidelberg, Germany
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