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An Efficient, One-Pot Regioselective Synthesis of Highly Functionalized Chromen-5-ones and Pyrano[3,2-c]chromen-5-ones via a Tandem Knoevenagel–Michael–Cyclization Sequence

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2012

Year

Abstract

A facile, convenient, efficient, and high-yielding regio­selective synthesis of a combinatorial library of hitherto unreported highly functionalized chromen-5-ones and pyrano[3,2-<i>c</i>]chromen-5-ones has been developed by one-pot three-component coupling of substituted aromatic aldehydes, dimedone/4-hydroxycoumarin with NMSM in the presence of catalytic amount of piperidine in ethanol medium. This transformation presumably proceeds via domino Knoevenagel condensation–Michael addition–intermolecular cyclization sequence creating three new bonds (two C–C and one C–O) and one stereocenter in a single operation.