[3,3]-Claisen rearrangements in 24α-methyl steroid synthesis
作者:Vladimir A. Khripach、Vladimir N. Zhabinskii、Olga V. Konstantinova、Natalya B. Khripach、Andrey P. Antonchick、Bernd Schneider
DOI:10.1016/s0039-128x(02)00007-7
日期:2002.6
campesterol starting from stigmasterol. The proposed approach is based on Claisen rearrangement of Delta23-22-allylic alcohols with various configurations of the 22-hydroxy group and geometry of the Delta23-double bond. It allows complete use of the starting steroid for preparing 24alpha-methyl derivatives. It was possible to partially control the stereochemistry at C-25. Hydrogenation of the Delta22-double