Diels-Alder chemistry of 2-cyanoalk-2-enones. A convenient general approach to angularly substituted polycyclic systems

Under zinc chloride catalysis, a number of 2-cyanoalk-2-enones representing various ring sizes were found to undergo facile cycloaddition with several selected conjugated dienes; sequential treatment of the adducts with lithi um naphthalenide and an alkylating agent resulted in the direct replacement of the angular cyano group with an alkyl group, providing easy access to a ngularly substituted polycyclic systems.