(+/-)-(2S,7aS)-5,7a-dimethyl-6-oxo-2,6,7,7a-tetrahydro-1H-inden-2-yl acetate 、
6,6-dimethyl-7-ethenyl-1,4-dioxaspiro[4.5]dec-7-ene 以
二氯甲烷 为溶剂,
反应 0.25h,
以65%的产率得到4,4,6b,9-tetramethyl-1,4,6,6a,6b,7,11a,11b-octahydrospiro-[benzo[a]fluorene-3,20-[1,3]dioxolan]-8(2H)-one