Efficient synthesis of fused bicyclic glutarimides. Its application to (+/-)-alloyohimbane and louisianin D.

[reaction: see text] The reaction of alpha-sulfonyl acetamide 1 with various cyclic unsaturated esters 2 to fused bicyclic glutarimides is reported. Syntheses of (+/-)-alloyohimbane (4) and louisianin D (5) have been accomplished.