Diastereoselective, vinylogous mukaiyama aldol additions of silyloxy furans to cyclic ketones: annulation of butenolides and gamma-lactones.

[reaction: see text] Vinylogous Mukaiyama aldol reactions employing silyloxyfurans and substituted cyclic ketones are described. These annulations proceed with moderate to good diastereoselectivity. The potential application of this process to the synthesis of butenolide and gamma-lactone containing natural products was demonstrated by further transformations of the addition products.