Cyclohexenones as Michael acceptors in the Staunton-Weinreb annulation: a simple stannane modification for the synthesis of polycyclic systems.

[reaction: see text] o-Toluate anions generated via transmetalation from the corresponding tributyl stannane underwent a Michael addition-Dieckmann condensation sequence with various cyclohexenones. This protocol provides an efficient entry into complex polycyclic systems without the use of beta-alkoxy enones hitherto required for the reaction.