Conversion of δ-(sulfonyl)amino-α-epoxy ketones to bicyclic ketopyrroles via intramolecular conjugate-addition to azoene intermediates. Synthesis of the bicyclic ketopyrrole core of the 1-azafulvene roseophilin

Article abstract of DOI:10.1016/0040-4039(96)00390-5

Reaction of δ-(sulfonyl)amino-α-epoxy ketones with dimethylhydrazine results in cyclization to pyrrolidine-fused β-hydroxy dimethylhydrazones. Hydrolysis, mesylation, and elimination affords dihydropyrroles which can be converted to sulfonyl-protected ketopyrroles via oxidation with NIS; alternatively, treatment with DBU affords N-H bearing ketopyrroles. Copyright