An efficient preparation of γ‐lactols and methylene‐γ‐lactols is described. Highly acid‐sensitive lactols are prepared in a concise manner by using a radical cyclization of aluminum acetals. The precursors for the radical reactions are readily prepared from allyl or propargyl alcohols and α‐bromo acids. Functionalization of the resulting γ‐lactols and methylene‐γ‐lactols can be achieved following isolation
描述了一种高效制备γ-内酯和亚甲基-γ-内酯的方法。通过使用
缩醛铝的自由基环化,以简明的方式制备高度酸敏感性的内酯。自由基反应的前体很容易由
烯丙醇或炔
丙醇和α-
溴酸制备。分离后即可实现所得γ-内酯和亚甲基-γ-内酯的功能化,从而产生了合成上有用的结构单元,例如1,4
-二醇,1,4-二烯,γ-内酯和多取代的
四氢呋喃。