Enantioselective synthesis of (S)- and (R)-mappicines and their analogues

Article abstract of DOI:10.1016/S0040-4020(99)00397-X

The naturally occurring alkaloids, camptothecin and mappicine ketone were converted to racemic mappicine acetate which was enantioselectively hydrolyzed to (S)- and (R)-mappicines in high optical purity using baker's yeast and a lipase, Amano PS. Treatment of the racemic acetate with baker's yeast afforded (S)-mappicine while with Amano PS yielded (R)-mappicine. 9- Methoxycamptothecin and 9-methoxymappicine ketone underwent similar conversion to (S)- and (R)-9-methxymappicines.