Isomerisation of 1-Alkynes to 2-Alkynes in the Nucleophilic Substitution of Acetylides

Abstract

1-Alkynes have been widely used as intermediates in the synthesis of natural products^1,2 and the absence of isomers and isomerisation is a prerequisite. Isomerisation of 1-alkynes under mild conditions during their preparation by nucleophilic substitution of acetylides has not been reported, and although this might be expected to occur only with the potassium and sodium derivatives we have found that excess of lithium acetylide is effective for such transformations.