Some alkali metal alkyl amides as alkyne isomerization reagents: selective isomerization of one triple bond of a diynol

Abstract

The lithium and sodium salts of 1,2-diaminoethane, 1,3-diaminopropane, n-butylamine, and the lithium salt of isobutylamine were studied as potential reagents for isomerization of triple bonds in alkyn-1-ols. The sodium salts of the diamines afforded high yields of the ω-alkyn-1-ol. Somewhat surprisingly, the sodium salt of n-butylamine also effects isomerization to the terminal position. The lithium salt of 1,3-diaminopropane gave the highest conversion of 2- to 3-alkyn-1-ol. A novel, selective rearrangement of one triple bond of a diynol, a 2, ω- to 3, ω-diyn-1-ol isomerization, was incorporated into a synthesis of the insect sex pheromone 3,13-octadecadienol acetate.