Preparation of alpha-functionalized alkenylmagnesium reagents via a halide-magnesium exchange

摘要

A general preparation of alkenylmagnesium derivatives bearing an electron-withdrawing function in the alpha-position (Y=CN, CO2R, CONR2, SO2Ph) has been made possible by using a low temperature (-40 to -30degreesC) bromine-magnesium exchange with i-PrMgBr in THF. This reaction has also been used to prepare 5-magnesiated-1,3-dioxin-4-one derivatives bearing an alkoxy substituent in beta-position to the carbon-magnesium bond. (C) 2002 Published by Elsevier Science Ltd. [References: 44]