STEREOSPECIFIC SYNTHESES OF THE DIASTEREOMERIC (+/-)-ALPHA-BISABOLOLS - CAVEAT ON THE ASSIGNMENT OF STEREOCHEMISTRY TO NATURAL ALPHA-BISABOLOL

The diastereomeric racemic (6S, 7S-6R, 7R)-α-bisabolol and (6S, 7R-6R, 7S)-α-bisabolol were stereospecifically synthesized from (6Z)-and (6©)1979, American Chemical Society.N-methylnitrones as the key ring- and stereochemistry-forming step. A subsequent reductive deamination of a quaternary ammonium salt afforded a mixture of the respective bisabolol and its Δ1 double-bond isomer in each case. NMR and gas chromatographic comparison of (-)-α-bisabolol isolated from chamomile oil with the two synthetic diastereomers showed the natural material to possess the 6S, 7S stereochemistry, in contrast to a previously reported assignment of 6S, 7R stereochemistry. In initial exploratory work, application of the synthetic sequence to citral smoothly yielded a-terpineol. © 1979, American Chemical Society. All rights reserved.