Manganese(III) acetate mediated oxidative radical cyclizations of α-substituted N-[(E)-stilben-2-yl]acetamides

Abstract

A synthetic method of 3-substituted 2-quinolinones from readily available α-substituted N-[(E)-stilben-2-yl]acetamides have been developed. α-Carbonylalkyl radical, produced by the manganese(III) acetate oxidation of N-[(E)-stilben-2-yl]acetamides, undergoes an intramolecular 6-exo-dig cyclization onto the CC bond efficiently and 2-quinolinones was produced. A variety of functional groups, including benzoyl, acetyl, cyano, and ethoxycarbonyl groups, are compatible with the reaction conditions. Under Mn(II)/Co(II)/O2 conditions, these N-[(E)-stilben-2-yl]acetamides were also converted into the corresponding 2-quinolinones effectively and a catalytic amount of manganese(II) acetate was used.