Short Total Synthesis of (±)-γ-Lycorane by a Sequential Intramolecular Acylal Cyclisation (IAC) and Intramolecular Heck Addition Reaction.

An intramolecular acylal cyclisation (IAC) approach to the synthesis of a range of bicyclic heterocycles is reported. As an example of the utility of the IAC reaction, the methodology was applied in a protecting-group-free five-step total synthesis of (±)-γ-lycorane, incorporating a new intramolecular Heck addition reaction to generate the pentacyclic core structure of the natural product in good yield.