LITHIUM ALKOXIDES OF CINCHONA ALKALOIDS AS CHIRAL CONTROLLERS FOR ENANTIOSELECTIVE ACETYLIDE ADDITION TO CYCLIC N-ACYL KETIMINES

Highly enantioselective acetylide addition to cyclic N-acyl ketimines 1 can be carried out using the lithium alkoxide of quinine as a stoich iometric chiral additive. Quinidine can be used to give the opposite e nantiomer. Optimization of temperature is critical, with low or high t emperatures reducing selectivity. Using the bulky 9-anthrylmethyl prot ecting group at a distal position on the imine, a 97% ee was achieved and applied to the asymmetric synthesis of HIV reverse transcriptase i nhibitor 3.