Phosphine-mediated cascade reaction of azides with MBH-acetates of acetylenic aldehydes to substituted pyrroles: a facile access to N-fused pyrrolo-heterocycles.

One-pot synthesis of substituted pyrroles by a cascade reaction of azides with Morita-Baylis-Hillman acetates of acetylenic aldehydes is described and the reaction is efficiently mediated by triphenyl phosphine at room temperature. Sodium azide is successfully used to provide N-unsubstituted pyrroles, while alkyl azides afforded the corresponding N-alkylated pyrroles through a sequence of allylic substitution/azide reduction/cycloisomerization reactions. The obtained products have provided a new entry to indolizino indoles, pyrrolo isoquinolines and 8-oxo-5,6,7,8-tetrahydroindolizine.

Morita-Baylis-Hillman acetates of acetylenic aldehydes: versatile synthons for substituted pyrroles via a metal-free tandem reaction.

A mild and metal-free access to 1,2,4-tri or 1,2,4,5-tetrasubstituted pyrroles has been developed by the reaction of Morita-Baylis-Hillman acetates of acetylenic aldehydes with amines and sulfonamides. This new protocol is based on K(2)CO(3)-promoted tandem allylic substitution/cycloisomerization reactions.