4-diaryl-substituted 4H-chromenes by the formal [4+1] cycloaddition reaction of o-quinone methides and pyridinium ylides followed by reductive rearrangement of 2-aroyl-2,3-dihydrobenzofurans by the action of zinc in acetic acid or samarium and trimethylchlorosilane in 1,4-dioxane. The reduction of 3-unsubstituted 2-aroyl-2,3-dihydrobenzofurans by the action of zinc in acetic acid leads mainly to 2-hydroxydihydrochalcones
提出了通过邻醌甲基化物和
吡啶鎓叶立德的形式 [4+1] 环加成反应然后还原重排合成 2-芳基和 2,4-二芳基取代的 4 H-色烯的两步程序。 2-芳酰基-
2,3-二氢苯并呋喃通
过乙酸中的
锌或
钐和 1,4-
二恶烷中的三
甲基氯硅烷的作用。通
过乙酸中
锌的作用还原 3-未取代的 2-芳酰基-
2,3-二氢苯并呋喃主要产生 2-羟基
二氢查耳酮。