3-(2,6-Dimethyl-hept-5-enylidene)-pentane-2,4-dione 在
zinc dibromide 作用下,
以
二氯甲烷 为溶剂,
反应 1.5h,
生成 1-((4aS,5R,7aR)-1,1,3,5-Tetramethyl-1,4a,5,6,7,7a-hexahydro-cyclopenta[c]pyran-4-yl)-ethanone 、 1-((4aS,5R,7aS)-1,1,3,5-Tetramethyl-1,4a,5,6,7,7a-hexahydro-cyclopenta[c]pyran-4-yl)-ethanone