methyl 3β-(tert-butyldimethylsilyloxy)-5α-pregnan-21-oate 、
1-溴-4-甲基戊烷 在
lithium diisopropyl amide 作用下,
反应 10.5h,
以75%的产率得到methyl (2R)-2-[(3S,5S,8R,9S,10S,13S,14S,17R)-3-[tert-butyl(dimethyl)silyl]oxy-10,13-dimethyl-2,3,4,5,6,7,8,9,11,12,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl]-6-methylheptanoate