Bromomethyl Ketones and Enolates: Alternative Products from Ester Homologation Reactions

Article abstract of DOI:10.1021/jo00225a032

Esters 1, in which R represents a primary alkyl, alkynyl, alkenyl, or aromatic substituent, were reacted with (dibromomethyl)lithium, followed by n-butyllithium.Bromomethyl ketone enolate anions 5 resulted, which were quenched with acid to afford bromomethyl ketones 4, generally in 70-85percent yields.Alternatively, enolate anions 5 could be quenched with acetic anhydride to afford bromo enol acetates 7 or treated with tert-butyllithium to produce α-keto dianions 8.