Catalytic, Asymmetric Synthesis and Diastereoselective Aldol Reactions of Dipropionate Equivalents
作者:Michael A. Calter、Wei Song、Jianguang Zhou
DOI:10.1021/jo035668l
日期:2004.2.1
methylketene can be conveniently prepared in one step and high enantiomeric excess from propionyl chloride, using a catalytic amount of a silylated cinchona alkaloid as a source of chirality. Opening of the dimer with a lithiated sulfonamide affords a β-ketosulfonimide, which undergoes Sn(II)-mediated aldol reactions to diastereoselectively afford the anti,syn-aldol adduct. Alternatively, reduction of the dimer