Enantioselective reduction of σ-Symmetric bicyclo[3.3.0]octane-2,8-diones with baker's yeast
摘要:
sigma-Symmetric bicyclic diketones 8a-c were enantioselectively reduced with baker's yeast to give the chiral hydroxy ketones 7a-c in 74-100% ee. The reduction product (+)-7a and (-)-7'c were shown to be the chiral intermediates for the total synthesis of cantabrenonic acids derivatives 3 and hirsutene (4), respectively. The subsequent transformation of (+)-7a gave the intermediate (+)-5 for the total synthesis of capnellenols (1, 2).