Synthesis of fused bicyclic glutarimides

We describe an efficient route towards the synthesis of fused bicyclic glutarimides using facile [3+3] reaction of α-sulfonylacetamides with different α,β-unsaturated esters as the key step. Intramolecular cyclization of 4-substituted 3-sulfonylglutarimide to form 5,6-, 6,6- or 6,7-fused bicyclic glutarimides was accomplished via alkylation, oxidative cyclization or ring-closing metathesis in modest yield.