TRANSITION-METAL-CATALYZED AUTOXIDATION OF CIS-PINANE AND TRANS-PINANE TO A MIXTURE OF DIASTEREOISOMERIC PINANOLS

Autoxidations of the pinanes, obtained after hydrogenation of naturall y occurring Pinus elliottii oil, were performed with or Without solven t, using the catalytic system Co(OAc)(2)/Mn(OAc)(2)/NH4Br in a 9:1:5 m olar ratio, and dioxygen as the oxidant. The best selectivity for the pinanols was 71% (cis:trans ratio, 3:1) with 17% conversion. Autoxidat ions were also carried out in the absence of catalyst. The hydroperoxi des formed with 17% conversion were decomposed with Na2SO3 and PPh3, r esulting in 62% pinanols (cis:trans ratio, 5:1). The pyrolysis of the pinanols at 600 degrees C and a contact time of 1.15 x 10(-2) s/mol yi elded 54% of linalool. The side products were mainly due to an ''ene'' reaction, giving diastereoisomeric 1,2-dimethyl-3-isopropenylcyclopen tanols.