Stereoselective reactions. 28. Effects of the alkyl group at the amide nitrogen of chiral bidentate lithium amides on enantioselective deprotonation reaction

Article abstract of DOI:10.1016/S0040-4020(97)00901-0

Enantioselective deprotonation of 4-substituted cyclohexanones (1a-d) by chiral bidentate lithium amides ((R)-2a-j) having an alkyl- or a fluoroalkyl substituent at the amide nitrogen was examined. (R)-2i having a 2,2,2-trifluoroethyl group at the amide nitrogen was found to be an excellent chiral base for the present deprotonation reaction. Structures of (R)-2i in solution and solid state are discussed.