Intramolecular Stetter reaction of methyl 3-(2-formylphenoxy)-prop-2-enoate catalyzed by 3-benzyl-5-(2-hydroxyethyl)-4-methyl-1,3-thiazolium chloride in refluxing dimethylformamide gave methyl 2,3-dihydro-3-oxobenzofuran-2-acetate in 39% yield. The presence of a tertiary amine, which in this case caused destruction of the product, is thus not necessary for the success of the Stetter reaction. When sodium cyanide was used as the catalyst, methyl 2-cyano-2,3-dihydro-4-hydroxy-2H-1-benzopyran-3-carboxylate was formed in 58% yield. Methyl 4-(2-formylphenoxy)but-2-enoate underwent intramolecular Stetter reaction to give methyl 3,4-dihydro-4-oxo-2H-1-benzopyran-3-acetate in 86% yield. Base-catalyzed cyclization of methyl 4-(2-formylphenoxy)but-2-enoate gave methyl-1-benzoxepin-4-carboxylate in 52% yield.
在 3-苄基-5-(2-羟乙基)-4-甲基-1,3-
噻唑氯化物的催化下,3-(2-甲酰基苯氧基)-2-
丙烯酸甲酯在回流的二甲基甲酰胺中发生分子内斯特特反应,生成 2,3-二氢-3-氧代
苯并呋喃-2-乙酸甲酯,产率为 39%。在这种情况下,叔胺的存在会导致生成物的破坏,因此斯泰特反应的成功并不需要叔胺的存在。当使用
氰化钠作为催化剂时,生成了 2-
氰基-2,3-二氢-
4-羟基-2H-1-苯并
吡喃-3-
甲酸甲酯,产率为 58%。4-(2-甲酰基苯氧基)丁-2-烯酸甲酯经过分子内斯特特反应生成 3,4-二氢-4-氧代-2H-1-苯并
吡喃-3-
乙酸甲酯,收率为 86%。在碱催化下,4-(2-甲酰基苯氧基)丁-2-烯酸甲酯发生环化反应,得到 1-苯并
氧杂卓-4-
甲酸甲酯,收率为 52%。