Exo‐ and endohormones. IX. Syntheses of Monounsaturated Sex Pheromones of Lepidoptera via 3‐alkyn‐1‐ols

Abstract

3‐Alkyn‐1‐ols as intermediate synthons in the preparation of some Lepidoteran sex pheromones were utilized. Characteristic fragmentations reflecting the position of the triple bond were found in the mass spectra of 3‐alkyn‐1‐ols and alkyn‐1‐yl acetates in contrast to 1‐tert.‐butoxy‐alkynes. A partial isomerization of 1‐tosyloxy‐3‐(Z)‐octene to 1‐bromo‐3‐(E)‐octene within the reaction with NaBr in DMF was noticed by GC and 13C‐n.m.r., for which a mecanism involving homoconjugation in an intermediate non‐classical carbonium ion was suggested.