5-己炔醛 、
(5R) ethyl δ-hydroxy-δ-phenyl-β-oxo-pentanoate 在
indium(III) triflate 作用下,
以
乙腈 为溶剂,
反应 6.0h,
生成
ethyl (2R,4aR,8aR)-5-methylidene-4-oxo-2-phenyl-2,3,6,7,8,8a-hexahydrochromene-4a-carboxylate 、 ethyl (2S,4aS,8aS)-5-methylidene-4-oxo-2-phenyl-2,3,6,7,8,8a-hexahydrochromene-4a-carboxylate