Synthesis of pennogenin utilizing the intact skeleton of diosgenin

The first synthesis of pennogenin, an aglycone of bioactive components of Chinese traditional medicine named "Chonglou"(Paris), starting from diosgenin, has been reported, which displays a new strategy of utilizing the resource compounds. According to this new strategy, the full and rational utilization of the intact skeleton and functional groups of starting material has been realized in the conversion of diosgenin to pennogenin. The key step for synthesis of pennogenin is the regioselective transformation of cholest-5-en-16,22-dion-3,26-diol to cholest5,16-dien-22-on-3,26-diol, which can be used to synthesize other bioactive steroids such as cephalostatin and OSW-1.