Enantioselective protonation of lithium enolates with chiral imides possessing a chiral amide

New chiral imides possessing a chiral amide can be prepared from 1,3,5-trim ethyl-r-1,c-3,c-5-cyclohexanetricarboxylic acid or related triacids and opt ically active amines. These imides are superior to 1,3,5-trimethyl-c-5-[(4S ,5S)-4,5-diphenyl-2-oxazolin-2-yl]-r-1,c-3-cyclohexanedicarboximide reporte d previously as a chiral proton source for enantioselective protonation of lithium enolates of 2-alkylcycloalkanones.