4,5,7,8-tetrahydro-9-hydroxy-6,10-dioxo-5-methyl-9-ethylbicyclo<4.2.1>nonano<3,4-b>furan-3-carboxylic acid methyl ester 在
对甲苯磺酸 作用下,
以
苯 为溶剂,
反应 5.0h,
以98%的产率得到4,5,7,8-tetrahydro-6,10-dioxo-5-methyl-9-ethylidenebicyclo<4.2.1>nonano<3,4-b>furan-3-carboxylic acid methyl ester