Dinuclear manganese alkoxide complexes as catalysts for C–N bond cleavage of simple tertiary NN-dialkylamides to give esters

摘要

Amide bonds are stable due to the resonance between the nitrogen lone pair and the carbonyl moiety, and therefore the chemical transformation of amides, especially tertiary amides, involving C–N bond fission is considered one of the most difficult organic reactions, unavoidably requiring harsh reaction conditions and strong acids or bases. We report the catalytic C–N bond cleavage of simple tertiary N,N-dialkylamides to give corresponding esters using a catalyst system (2 mol% based on Mn atoms) of a tetranuclear manganese alkoxide, [Mn(acac)(OEt)(EtOH)]4 (>1c), combined with four equivalents of 4,7-bis(dimethylamino)-1,10-phenanthroline (>L1: Me2N-Phen). Regarding the reaction mechanism, we isolated a dinuclear manganese complex, [Mn(acac)(OEt)(Phen)]2 (>6c), which was revealed as the catalytically active species for the esterification of tertiary amides.