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
Lithio dichloromethyl phenylsulfoxide reacts with aldehydes and alkylhalides to give the corresponding addition and alkylated products respectively. Pyrolysis of these compounds result in the formation of dichloroketones and terminal vinyl dichlorides.