无介质微波作用下酮与稳定叶立德的反应

Medium free wittig reaction of stabilized ylides with ketones under microwave irradiation

酮与稳定膦叶立德在家用微波炉中加热,在无任何溶剂或固体介质条件下,4.5min之内完成反应,得到了良好产率的Wittig反应产物.较之液相苯中回流反应的传统方法,此法具有时间短、操作步骤简单、无毒害等优点.同时使一些在传统方法中与稳定叶立德不反应或难反应的酮得以进行并有较好收率.此外,在得到α,β-不饱和酯的同时,还发现了少量重排产物β,γ-不饱和酯,并对其机理进行了推测与证明.

Ketones and stabilized phosphorus ylides were heated together in commercial microwave oven, under solvent and medium free conditions, the Wittig reaction finished within 4.5 minutes, the yield was moderate. Compared with conditional method in benzene, the method had many merits such as its fastness, simplicity of operation harmless etc. At the same time, some ketones that could not react with stabilized ylides in conditional way could react by using this method and had good yields. What's more, besides the main product of α,βunsaturated ester, a little rearrangement product,β,γ unsaturated ester was found. The rearranging mechanism was also suggested and proved.