Studies on steroidal plant-growth regulators. Part 33. Novel method for construction of the side-chain of 23-arylbrassinosteroids via Heck arylation and asymmetric dihydroxylation as key steps

Abstract

An efficient method for construction of the 23-arylbrassinosteroidal side-chain is described via Heck coupling and asymmetric osmylation as key steps. Several new (22R, 23R)-23- arylbrassinosteroids were synthesized. The overall yields of 23-phenylbrassinosteroid 18 and the new compound 13a from 22-olefin 7 were 10%(seven steps) and 37%(five steps), respectively.