Intramolecular alkylation of ketones is an attractive and popular synthetic route to polycyclic ketones. In most cases the synthetic scheme is designed such that only one mode of cyclization is possible. We here describe the intramolecular alkylations of a series of bicyclic a,@-unsaturated ketones (1, 2, and 3) in la, X= Br 2 3 b, X= OMS which, a priori, three possibilities for cyclization exist, ie, alkylation at the a posit'ion, at the y position, or at the a' ...
