Catalytic asymmetric epoxidation of α,β-unsaturated N-acylpyrroles as monodentate and activated ester equivalent acceptors

Catalytic asymmetric epoxidation of alpha,beta-unsaturated N-acylpyrroles as monodentate and activated ester equivalent acceptors is described. A Sm(O-i-Pr)(3)/(R)-H-8-BINOL complex promoted the epoxidation reaction to afford products in high yield (up to quant) and high enantiornefic excess (up to > 99.5% ee). Reaction proceeded smoothly using cumene hydroperoxide (CMHP) with low explosive hazard, and completed within 0.2-0.5 h with 5 mol % catalyst. Catalyst loading was successfully reduced to as little as 0.02 mol %. The N-acylpyrrole properties as well as efficient synthesis of oc, -unsaturated N-acylpyrroles are also described. (c) 2006 Elsevier Ltd. All rights reserved.