Cu(i)-catalyzed chemical fixation of CO2 with 2-alkynylaniline into 4-hydroxyquinolin-2(1H)-one

Abstract

A copper(I) catalyzed reaction of 2-alkynylaniline with CO₂ using DBU as base to produce 4-hydroxyquinolin-2(1H)-one derivatives in moderate to good yield is presented. In this reaction, a unique bond cleavage pattern for CO₂ was observed that one of the C–O double bonds of CO₂ was totally broken and rearranged into two moieties in the absence of the reductive reagent. This efficient reaction system showed the wide generality of substrates including nitro, bromo, cyano and methoxylcarbonyl groups. A possible mechanism containing isocyanate intermediate is proposed.