Steroidal derivatives having a bicyclo [3. 2. 1] octane bridged ring of the phyllocladene type on the A ring such as compounds (IVa), (IVb), (XXIV) and (VIIIa) were synthesized starting from 5α-cyanocholestan-3-one by three routes. The route consisting of conversion of the cyano group into an acetyl group, and subsequent cyclization was found to be most preferable for the synthesis.
以 5α-
氰基胆甾烷-3-
酮为起始原料,通过三种途径合成了 A 环上具有双环 [3.其中,将
氰基转化为
乙酰基,然后进行环化的合成路线最为可取。