New approaches to the preparation and transformation of acetylenic compounds via KAPA superbase chemistry

Abstract

KAPA is a new alkamide superbase which is readily prepared from potassium hydride and 3-aminopropylamine and used in solutions of the excess amine, and which shows exceptional activity for base-catalyzed reactions involving proton abstraction, such as olefin and acetylene isomerization, aryl carbon-hydrogen isotopic exchange, and elimination. Thus, 3-hexyne is converted by KAPA at 0/sup 0/C to potassium 1-hexynide, which is then hydrolyzed to 1-hexyne in 96Vertical Bar3< yield. Alkynes with longer chains such as 4-octyne, 7-tetradecyne, and methylnonynes, readily undergo triple-bond migration to the chain terminus via the rapid and mild ''acetylene zipper'' isomerization.