Bicyclic Systems Related to Taxol. A Direct Means for Implementing C-2 Oxygenation and Demonstration of the Feasibility of alpha-Ketol Equilibration in a Fully Oxygenated B-Ring Setting.
The feasibility of alpha-ketol equilibration in a fully oxygenated B-ring setting for the rapid, enantioselective construction of an A/B bicyclic model related to Taxol has been examined. The key elements associated with this successful venture include selection of a proper array of protecting groups for the four hydroxyl groups present, suitable catalysis of the 1,2-pinacol-like shift, and an intrinsic dependence on the thermodynamic stabilities of the two alpha-ketol isomers. The key conversion of 13 to 14 is seen to be unidirectional and consequently to offer useful potential serviceability as more advanced thrusts toward Taxol are mounted.
Zeng
Qingbei
Q
Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210.
Bailey
Simon
S
Wang
Ting-Zhong
TZ
Paquette
Leo A.
LA