[3,3]-Claisen rearrangements in 24 alpha-methyl steroid synthesis - Application to campesterol, crinosterol, and delta(25)-crinosterol side chain construction

This paper elaborates an improved synthesis of crinosterol and campesterol starting from stigmasterol. The proposed approach is based on Claisen rearrangement of Delta(23)-22-allylic alcohols with various configurations of the 22-hydroxy group and geom