苯甲醛二甲缩醛 、
(3aR,4S,7S,7aR)-3a,7-Dihydroxy-4-hydroxymethyl-6-methyl-3a,4,7,7a-tetrahydro-benzofuran-3-one 在
对甲苯磺酸 作用下,
以
二氯甲烷 为溶剂,
生成 (2R,4aS,7S,7aR,10aR)-7-Hydroxy-6-methyl-2-phenyl-4,4a,7,7a-tetrahydro-furo[3',2':2,3]benzo[2,1-d][1,3]dioxin-10-one 、 (2S,4aS,7S,7aR,10aR)-7-Hydroxy-6-methyl-2-phenyl-4,4a,7,7a-tetrahydro-furo[3',2':2,3]benzo[2,1-d][1,3]dioxin-10-one