Enantioselective synthesis of alpha-methyl-beta-aminoacid derivatives via aza-aldol reaction of acylcamphorsultam enolates

The aza-aldol reaction of the chiral enolate derived from (2S)-N-propionoyl camphor sultam 1 with certain N-diphenylphosphinyl imines furnishes N-(2R, 3R-α-methyl-β-diphosphinylamido)acylsultams, in acceptable to good yields and with virtually complete diastereo- and enantiocontrol. The method represents an operationally-simple route for preparation of α-methyl-β-aminoacids from readily-available starting materials.