STEREOSELEKTIVE TOTALSYNTHESE VON (+/-)-TORREYOL

Article abstract of DOI:10.1016/S0040-4020(01)91500-5

Enones of formulae Ia-d undergo cyclization to give stereoselectively the enol esters IIa-d, respectively.IIa-d are suitable synthones for some sesquiterpene syntheses.-In this paper the synthesis of torreyol (1) is described by an all step strereocontrolled reaction sequence: cyclization educt 10 (Ic) was prepared by alkylation of 8 with 5 and enol ether cleavage of 9.The reaction sequence 11a (IIc)<*>14a 15<*>18 (ester hydrolysis, formation of the tert. alcohol, degradation of the isopropenyl group) followed by oxidation resulted in the formation of ketone 19 whose relative configuration was determined by the 2D J-resolved 400 MHz (1)H NMR spectrum.After methylation at C-8 (22<*>23) the tosylhydrazone 25 underwent Bamford-Stevens reaction to yield (+/-)-1.