Palladium-Catalyzed α-Arylation of Esters with Chloroarenes

Palladium-catalyzed alpha-arylations of esters with chloroarenes are reported. The reactions of chloroarenes with the sodium enolates of tert-butyl propionate and methyl isobutyrate occur in high yields with 0.2-1 mol % of {[P(t-Bu)3]PdBr}2 or the combination of Pd(dba)2 and P(t-Bu)3 as catalyst. The reactions of chloroarenes with the Reformatsky reagent of tert-butyl acetate were most challenging but occurred in high yields for chlorobenzene and electron-poor chloroarenes catalyzed by 1 mol % of Pd(dba)2 and pentaphenylferrocenyl di-tert-butylphosphine (Q-phos).