Enantioselective Decarboxylative α-Alkynylation of β-Ketocarbonyls via a Catalytic α-Imino Radical Intermediate.

A distinctive aminocatalysis via α-imino radical is reported on the basis of SET oxidation of a secondary enamine. The combination of chiral primary amine catalysis and visible-light photoredox catalysis enables the enantioselective decarboxylative coupling of propiolic acid and β-ketocarbonyls to afford alkynylation adducts with high enantioselectivity. Mechanism studies indicate the reaction proceeds via an α-imino radical addition.

[1]  Haijun Yang,et al.  Visible-light photoredox synthesis of internal alkynes containing quaternary carbons. , 2016, Chemical communications.

[2]  Guojin Zhang,et al.  Dual Hypervalent Iodine(III) Reagents and Photoredox Catalysis Enable Decarboxylative Ynonylation under Mild Conditions. , 2015, Angewandte Chemie.

[3]  Long Zhang,et al.  Pushing the limits of aminocatalysis: enantioselective transformations of α-branched β-ketocarbonyls and vinyl ketones by chiral primary amines. , 2015, Accounts of chemical research.

[4]  Yiyun Chen,et al.  Hypervalent iodine reagents enable chemoselective deboronative/decarboxylative alkenylation by photoredox catalysis. , 2015, Angewandte Chemie.

[5]  Long Zhang,et al.  Asymmetric α-photoalkylation of β-ketocarbonyls by primary amine catalysis: facile access to acyclic all-carbon quaternary stereocenters. , 2014, Journal of the American Chemical Society.

[6]  K. Maruoka,et al.  Efficient asymmetric synthesis of spiro-2(3H)-furanones via phase-transfer-catalyzed alkynylation. , 2014, Organic & biomolecular chemistry.

[7]  Jindian Duan,et al.  Asymmetric organocatalysis mediated by primary amines derived from cinchona alkaloids: recent advances , 2014 .

[8]  L. Qu,et al.  Cu/Ag-catalyzed double decarboxylative cross-coupling reaction between cinnamic acids and aliphatic acids in aqueous solution , 2013 .

[9]  Fernanda G. Finelli,et al.  Enantioselective intramolecular aldehyde α-alkylation with simple olefins: direct access to homo-ene products. , 2013, Journal of the American Chemical Society.

[10]  J. Waser,et al.  Ethynylbenziodoxolones (EBX) as Reagents for the Ethynylation of Stabilized Enolates , 2013 .

[11]  P. Melchiorre.  Cinchona-based primary amine catalysis in the asymmetric functionalization of carbonyl compounds. , 2012, Angewandte Chemie.

[12]  Fernanda G. Finelli,et al.  Enantioselective organo-SOMO cycloadditions: a catalytic approach to complex pyrrolidines from olefins and aldehydes. , 2012, Journal of the American Chemical Society.

[13]  D. MacMillan,et al.  The Intramolecular Asymmetric Allylation of Aldehydes via Organo-SOMO Catalysis: A Novel Approach to Ring Construction. , 2011, Chemical science.

[14]  D. MacMillan,et al.  Direct and enantioselective α-allylation of ketones via singly occupied molecular orbital (SOMO) catalysis , 2010, Proceedings of the National Academy of Sciences.

[15]  J. Waser,et al.  Ethynyl-1,2-benziodoxol-3(1H)-one (EBX): an exceptional reagent for the ethynylation of keto, cyano, and nitro esters. , 2010, Chemistry.

[16]  J. Conrad,et al.  Mechanistic complexity in organo-SOMO activation. , 2010, Angewandte Chemie.

[17]  Jeffrey F. Van Humbeck,et al.  Concerning the mechanism of the FeCl3-catalyzed alpha-oxyamination of aldehydes: evidence for a non-SOMO activation pathway. , 2010, Journal of the American Chemical Society.

[18]  D. MacMillan,et al.  Enantioselective organo-SOMO cascade cycloadditions: a rapid approach to molecular complexity from simple aldehydes and olefins. , 2010, Journal of the American Chemical Society.

[19]  D. MacMillan,et al.  Enantioselective polyene cyclization via organo-SOMO catalysis. , 2010, Journal of the American Chemical Society.

[20]  K. Houk,et al.  Nature of intermediates in organo-SOMO catalysis of alpha-arylation of aldehydes. , 2010, Journal of the American Chemical Society.

[21]  D. MacMillan,et al.  Enantioselective aldehyde alpha-nitroalkylation via oxidative organocatalysis. , 2009, Journal of the American Chemical Society.

[22]  J. Conrad,et al.  Enantioselective alpha-arylation of aldehydes via organo-SOMO catalysis. An ortho-selective arylation reaction based on an open-shell pathway. , 2009, Journal of the American Chemical Society.

[23]  K. Jørgensen,et al.  Organocatalysis--after the gold rush. , 2009, Chemical Society reviews.

[24]  Sean P. Brown,et al.  Enantioselective linchpin catalysis by SOMO catalysis: an approach to the asymmetric alpha-chlorination of aldehydes and terminal epoxide formation. , 2009, Angewandte Chemie.

[25]  Yixin Lu,et al.  Asymmetric catalysis with chiral primary amine-based organocatalysts. , 2009, Chemical communications.

[26]  Casey M. Jones,et al.  Enantioselective organo-singly occupied molecular orbital catalysis: the carbo-oxidation of styrenes. , 2008, Journal of the American Chemical Society.

[27]  Armando Carlone,et al.  Asymmetric aminocatalysis--gold rush in organic chemistry. , 2008, Angewandte Chemie.

[28]  S. Mukherjee,et al.  Asymmetric enamine catalysis. , 2007, Chemical reviews.

[29]  D. MacMillan,et al.  Enantioselective Organo-SOMO Catalysis : The α-Vinylation of Aldehydes , 2007 .

[30]  Hye‐Young Jang,et al.  Enantioselective organocatalytic singly occupied molecular orbital activation: the enantioselective alpha-enolation of aldehydes. , 2007, Journal of the American Chemical Society.

[31]  J. Overgaard,et al.  Organocatalytic Asymmetric Direct a-Alkynylation of Cyclic -Ketoesters. , 2007 .

[32]  Che-Ping Chuang,et al.  Synthesis of highly substituted pyrroles via oxidative free radical reactions of β-aminocinnamates , 2006 .

[33]  Che-Ping Chuang,et al.  A novel oxidative free radical reaction between 2-hydroxy-1,4-naphthoquinone and β-enamino carbonyl compounds , 2001 .

[34]  Leblanc,et al.  Metallic salt promoted radical cyclization of beta-keto carboxamides and their corresponding beta-enamino carboxamides , 2000, The Journal of organic chemistry.

[35]  J. Cossy,et al.  Manganese(III) acetate and copper(II) acetate promoted oxidation of β-enaminoamides and β-enaminoesters , 1999 .

[36]  P. Audebert,et al.  Electrochemical evidence for intramolecular reactions of the electrogenerated cation — Radicals of some amidoenamines , 1995 .

[37]  Ken Tanaka,et al.  Generation of Cation Radicals from Enamines and Their Reactions with Olefins , 1992 .

[38]  P. Renaud,et al.  Reductive Alkylation of Enamines with Chloromethyl p‐Tolyl Sulfone via a Radical Chain Process , 1990 .

[39]  Jin‐Pei Cheng,et al.  Radical-cation acidities in solution and in the gas phase , 1989 .

[40]  J. Niemann,et al.  On the electrochemical oxidation of enamines , 1988 .

[41]  W. Eilenberg,et al.  Anodic intramolecular arylation of enaminones , 1985 .

[42]  M. Okimoto,et al.  Electrochemical oxidation of enamines in the presence of organic anions , 1979 .

[43]  T. Shono,et al.  Electroorganic Chemistry. XXVI. Electrooxidation of Enamines, Haloolefins, and Enol Ethers , 1978 .