Bromine-magnesium-exchange as a general tool for the preparation of polyfunctional aryl and heteroaryl magnesium-reagents
作者:Mohamed Abarbri、Florian Dehmel、Paul Knochel
DOI:10.1016/s0040-4039(99)01404-5
日期:1999.10
BrMg-exchange reaction for the preparation of polyfunctional aryl and heteroaryl magnesium reagents has been studied. Various functional groups (ester, cyano, bromide) were tolerated in the exchange reaction allowing the preparation of polyfunctional Mg-reagents. Several dibromo- or tribromoheterocycles undergo a chemoselective mono-BrMg exchange leading to highlyfunctionalized heterocycles.
iodine-magnesium exchange. In many cases, the exchange can be extended to heteroaryl bromides, and a case of a chlorine-magnesium exchange is described with tetrachlorothiophene. This new preparation of functionalized heteroarylmagnesium compounds provides after reaction with various electrophiles a new entry to a broad range of polyfunctional pyridines, imidazoles, furanes, thiophenes, pyrroles, antipyrines