8-[(1S,3aS,7aS)-1-tert-butoxy-7a-methyl-2,3,3a,6,7,7a-hexahydro-1H-inden-5-yl]-1,4-dioxaspiro[4,5]dec-7-ene 、
富马酸二甲酯 以
苯 为溶剂,
反应 12.0h,
以45%的产率得到dimethyl (13S,14S,17S)-17-tert-butoxy-13-methylspiro(1',3'-dioxolane[2',3]-2,3,4,5,6,7,8,11,23,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]-phenanthrene-6,7-dicarboxylate)