The key steps were the stereospecific conversion of both allylie carbamates 10 and 13 into 11 by Li_2Cu_3(CH_2)_5 and the stereoselective hydroxylation of unsaturated side chain by OsO_4-NMO.

• 合成的关键步骤是用Li_2Cu_3(CH_3)_5立体专一地转化烯丙醇苯胺基甲酸酯10和13成为11和用OsO_4-NMO在化合物16的不饱和侧链上立体选择性羟基化。