Synthesis of Acetylenic Carboxylic Acids

Abstract
A recent communication by Brattesani and Heathcock1 on the alkylation of acetylenes with alkyl halides in hexamethylphosphoramide (HMPA) prompts us to report our work which is of a similar nature. We were interested in preparing acetylenic acids of formula 1 by either of the following two routes: The published procedure, which gives variable results, for the preparation of acetylenic acids via route (1) involves the condensation of a lithio-alkyne with an ωl -bromo-acid in liquid ammonia-tetrahydrofuran.