ethyl (E)-4-methylhexa-3,5-dienyl fumarate 在
1-ethyl-3-methylimidazolium tetrafluoroborate 作用下,
反应 5.0h,
生成 (4aR*,8R*,8aR*)-ethyl 5-methyl-1-oxo-3,4,4a,7,8,8a-hexahydro-1H-isochromene-8-carboxylate 、 (4aR*,8S*,8aS*)-ethyl 5-methyl-1-oxo-3,4,4a,7,8,8a-hexahydro-1H-isochromene-8-carboxylate