--LACTONE DERIVATIVES AND PROCESS OF PREPARING SAME

摘要

Novel ?-lactone derivatives which are useful as intermediate for a synthesis of brassinolide, epibrassinolide or bisnorbassinolide and a process of preparing them are disclosed. According to the process of the present invention, the introduction of carbon chains which form polyhydroxylated steroid side chains of brassinolides or the like into steroid nucleus is carried out in one step with the control of stereochemistry of the contiguous four acyclic chiral centers.