Intramolecular C-H insertion by an alkylidene carbene: Diastereoselective synthesis of a taxol A ring synthon

Article abstract of DOI:10.1021/jo00099a035

The first stage in a proposed total synthesis of the clinically effective anticancer agent taxol 1 is reported. A key step in this synthesis is the development of a new procedure for the generation and cyclization of the alkylidene carbene derived from ketone 9, to give cyclopentene 16 (formation of three new carbon-carbon bonds) in 72% yield. Ozonolysis of 16 followed by aldol condensation furnished the crystalline cyclohexenone 4.