Enantioselective reductive coupling of 1,3-enynes to glyoxalates mediated by hydrogen: asymmetric synthesis of beta,gamma-unsaturated alpha-hydroxy esters.
Catalytic hydrogenation of 1,3-enynes 1a-8a in the presence of ethyl glyoxalate at ambient pressure and temperature using a rhodium catalyst modified by (R)-(3,5-tBu-4-MeOPh)-MeO-BIPHEP results in highly regio- and enantioselective reductive coupling to furnish the corresponding alpha-hydroxy esters 1b-8b. As demonstrated by the elaboration of alpha-hydroxy ester 1b, the terminal and internal olefin moieties embodied by the diene side chain are subject to selective manipulation, one over the other.
Hong
Young-Taek
YT
University of Texas at Austin, Department of Chemistry and Biochemistry, Austin, Texas 78712, USA.
Cho
Chang-Woo
CW
Skucas
Eduardas
E
Krische
Michael J
MJ
D002384:Catalysis; D004952:Esters / Q000138:chemical synthesis* / Q000737:chemistry; D005030:Ethylenes / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D015394:Molecular Structure; D010070:Oxalates / Q000737:chemistry*; D013237:Stereoisomerism
D004952:Esters; D005030:Ethylenes; D010070:Oxalates; D006859:Hydrogen; C036216:ethylene