Microwave Assisted Michael Additions of N-(Arylsulfonyl)pyrroles

Abstract

<p>The Michael type addition of methyl vinyl ketone (MVK) to pyrroles bearing strongly electron withdrawing N-protecting groups (e.g., arylsulfonyl) have yet to be reported. We find that such alkylative processes can be effected in moderate yields using metal triflate catalysts in conjunction with microwave irradiation. Optimization of reaction conditions indicates that of the catalysts examined (rare earth triflate and chlorides) and solvents (nitromethane, acetonitile, dichloroethane, methanol, etc.) highest yields of monoalkylated derivatives are obtained using bismuth triflate (10 mol%) in tetrahydrofuran as solvent. Similar attempts employing acrylonitrile or ethyl acrylate failed to produce appreciable alkylation.</p><p>This presentation occurred at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 16, 2010</p>