Ligand exchange reaction of sulfoxides in organic synthesis: A new synthesis of α-chloroketones from carbonyl compounds with one-carbon homologation

Abstract

A new procedure for one-carbon homologation of carbonyl compounds to α-chloroketones is described. Addition of the carbanion of dichloromethyl phenyl sulfoxide with ketones and aldehydes gave the adducts, chloro alcohols, in good yields. Treatment of the chloro alcohols with EtMgBr or lithium diisopropylamide gave one-carbon homologated α-chloroketones via β-oxido carbenoid rearrangement in moderate to good yields. One-carbon homologation of esters to α-chloroketones was realized via the ligand exchange reaction of the sulfinyl group of α-chloro α-sulfinyl ketones, which were synthesized from methyl esters and chloromethyl phenyl sulfoxide, with EtMgBr.