AN ENANTIOSELECTIVE APPROACH TO THE TAXANES - DIRECT ACCESS TO FUNCTIONALIZED CIS-TRICYCLO[9.3.1.0(3,8)]PENTADECANES VIA ALPHA-HYDROXY KETONE AND WAGNER-MEERWEIN REARRANGEMENTS

The feasibility of the titled reactions for the rapid, enantioselective synthesis of cis-tricyclo[9.3.1.0(3,8)]pentadecane precursors to taxusin and taxol has been examined. The catalysts most well suited to inducing the appropriate 1,2-shifts have been identified. To a great extent, the rearrangement products are formed as a direct consequence of appropriate structural features (kinetic phenomenon) and strain minimization (thermodynamic driving force). Complementary MM2 calculations of the global minimum in each series provided indications that were completely in line with the experimental observations. Sophisticated NMR studies and X-ray crystallographic determinations were coordinated to remove any ambiguity of product structure and solid-state conformation.