The Taxol family of molecules has commanded the attention of the most important synthetic organic chemists due to their unusual tetracyclic structure and, more importantly, to their potent anti-cancer properties. In this project it is intented to develop a new synthetic strategy towards this family of compounds, in which two major fragments are coupled at a late stage in the sequence, and Band C-rings are cyclised in a single step via cation-mediated cascade cyclisation. The cyclohexenyl A-ring acts as a spacer group between the oxetane D-ring acetal and the nucleophilic propargylic silane terminator.
The termodynamic driving force for the sequential C-C bond formation will be as a result of formation of increasingly stabilised carbocationic species down the cascade. The novelty of this strategy lies in the cyclisation of a precursor containing intact A and D rings to form B and C rings.