Temperature Effects on Stereocontrol in the Horner−Wadsworth−Emmons Condensation of α-Phosphono Lactones
作者:Jose S. Yu、David F. Wiemer
DOI:10.1021/jo070722+
日期:2007.8.1
The Horner−Wadsworth−Emmons condensation of some α-phosphono lactones has been examined for conditions that impact product stereochemistry. The temperature employed to quench the reaction was found to be a major factor. For example, after the diethyl phosphonate derivative of γ-butyrolactone was treated with potassium hexamethyldisilazane, 18-crown-6, and propionaldehyde at −78 °C in THF, an aliquot
对某些α-膦酰基内酯的霍纳-沃兹沃思-埃蒙斯缩合反应进行了影响产物立体化学的条件研究。发现用于淬灭反应的温度是主要因素。例如,将γ-丁内酯的二乙基膦酸酯衍生物在THF中在-78°C下用六甲基二硅氮烷钾,18-crown-6和丙醛处理后,等分试样转移到约30°C的烧瓶中,几乎得到Z -烯烃产物,尽管允许其在数小时内升温至室温,却非常有利于E-烯烃。