A simple and unambiguous synthesis of α,α- and α,α′-dihalogeno ketones

A convenient method for the unambiguous preparation of α,α′-dihalogeno ketones 3 from in situ generated chloromethyllithium and α-chloro or α-bromo carboxylic acid esters 1 at –78 °C, is described. The unambiguous preparation of α,α-dihalogeno ketones 7 by using in situ-generated dihalogenomethyllithium and carboxylic acid esters 5 at –78 °C is also reported.