Silver-Catalyzed Functionalization of Esters by Carbene Transfer: The Role of Ylide Zwitterionic Intermediates

The reaction of esters with ethyl diazoacetate catalyzed by the complex [F₂₇–TpAg(acetone)] generates α-(acyloxy)acetates in moderate to high yields. This is a novel transformation in the context of carbene-transfer reactions from diazo compounds that, according to experimental and theoretical data, is suggested to occur through zwitterionic intermediates.