Novel synthesis of ynolates via the cleavage of ester dianions: α-Bromo and α,α-dibromo esters as precursors

Abstract

Ynolates have been synthesized via the thermally-induced cleavage of ester dianions. The key intermediates, ester dianions, were generated from α-bromocarboxylic acid ester enolates via lithium halogen exchange. α,α-Dibromocarboxylic acid ester also gives lithium amide free ynolates by addition of tert-BuLi. The reactions of ynolates, generated by this novel and convenient method, with aldehydes to give β-lactons are discussed.