A highly regioselective, protecting group controlled, synthesis of bicyclic compounds via Pd-catalysed intramolecular cyclisations

Intramolecular Pd-catalysed cyclisation reactions for the preparation of bicyclic compounds have been studied as a model system towards the synthesis of corialstonine and corialstonidine. Significant differences in reactivity have been observed for the cyclic allyl alcohols possessing O-protected and free OH functionalities. Cyclisation via the intramolecular Heck reaction, for both derivatives, proved to be highly regioselective and while the O-protected compound favoured the exo mode of cyclisation, the unprotected alcohol preferred the endo cyclisation pathway. Brief computational studies were carried out in order to obtain further insight into these processes.