2,2,5,8-Tetramethyl-7-methylene-3,4-dihydro-2H,7H-chromen-6-one 以
乙醚 、 Petroleum ether 为溶剂,
生成
3,3',4,4',8,9-hexahydro-2',2',5,5',7,7,8',10-octamethylbenzo<1,2-b:4,5-b'>dipyran-2-spiro-7'(6'H)-<1>benzopyran-6'-one 、 3',4,4',7,8,9,10',11',12',15'-decahydro-2',2',5,5',7,7,7a',9',10,12',12',14'-dodecamethylbenzo<1,2-b:4,5-b'>dipyran-2(3H)-spiro-7'(2'H)-xantheno<6,7-b:9a,1-b'>dipyran-6'-one