A novelapproach to the synthesis of the orally active estrogen 14 alpha,15 alpha-methylene estradiol (8, J 824) is described, starting with 3-methoxy-estra-1,3,5(10),8,14-pentaen-17 alpha-ol (5). The 14 alpha, 15 alpha-methylene bridge was sonochemically introduced by regioselective and stereoselective Simmons-Smith methylenation of the 14-double bond. Birch reduction of the 8-double bond provided
A concise total synthesis of C(14)C(15) methylene-bridged equilenin derivatives
作者:H. Künzer、M. Thiel
DOI:10.1016/0040-4039(94)85211-1
日期:1994.4
reaction sequence including hydroxyl group-assisted cyclopropanation, C(17)-oxidation, B-ring aromatization, C(17)-reduction, and methyl ether cleavage has been devised to convert 2 into 12. The synthesis of 19 took advantage of a facile isomerization of vinyl(benzyl)cyclopropane derivatives 6–11 into the corresponding β-bridged analogues 13–18 over molecular sieves.