Results (Dichloromethy1) lithium was prepared from butyllithium and dichloromethane in tetrahydrofuran (THF) at-100 OC5J1 and then treated with the boronic ester 1 to be homologated. The resulting solution was allowed to stand at room temperature overnight in order to rearrange the intermediate borate complex (2) to the a-chloro boronic ester (31, which was isolated simply by filtering the precipitated lithium chloride and distilling the ...
