Stereospecific synthesis of S-(-)-trans-verbenol and its antipode by inversion of sterically hindered alcohols

S-(-)-trans-Verbenol (1) and its antipode, R-(+)-trans-verbenol (1 ') have been confirmed as the critical pheromone components of bark beetles. Synthesis of these two active secondary alcohols (1 and 1 ') from commercially available starting materials S-alpha-pinene and R-alpha-pinene was reported. The key steps were mainly depended on the effective S(N)2 stereo-inversion of the hydroxy group of sterically hindered alcohols (3 and 3 '), using Mitsunobu reaction or hydrolysis of mesylate ester, alternatively. Our results provide a new and stereo-selectivity way to obtain optically active insect pheromones.