is described. This preparation makes use of the condensation of titanium enolates derived from β-hydroxy ketones with phosgene iminium chloride or trimethylorthoformate, respectively. The in situ formation of the necessary titanium complex from an aldol condensation using simple ketone and aldehyde precursors makes for a one-pot double condensation synthesis of the desired dihydropyrones.
描述了合成2-
氨基-5,6-二氢-4 H-
吡喃-4-酮和5,6-二氢-4 H-
吡喃-4-酮的替代方法。该制备方法利用了衍生自β-羟基酮的烯醇
钛酸酯与
光气氯化
亚胺氯化铵或
原甲酸三甲酯的缩合反应。在原位形成了必要的
钛从使用简单的酮和醛前体的醛醇缩合复杂的使得所希望的dihydropyrones一锅双缩合合成。