Pheromone synthesis. XII. Synthesis of optically pure (1S,4S,5S)-2-pinen-4-ol (cis-verbenol) and its antipode, the pheromone of Ips bark beetles.

Abstract

The enantiomers of cis-verbenol (4a' and 4a) were first synthesized in optically pure state. (1S, 4S, 5S) -2-Pinen-4-ol (4a') was dextrorotatory in acetone or in methanol but it was levorotatory in chloroform; cis-verbenols are indistinguishable by a prefix (+) or (-). The designation of the Ips pheromone as (+) -cis-verbenol is therefore ambiguous and it should be called as (1S, 4S, 5S) -2-pinen-4-ol (4a') or (S) -cis-verbenol.