Gold(I)-catalyzed homologation of aryl aldehydes with trimethylsilyldiazomethane.

A methodology is described herein for the synthesis of 2-aryl acetaldehydes from aryl aldehydes using TMSCHN 2 under Au(I) catalysis. A diazoorgano Au(I) complex was shown to be an intermediate that reacts with ArCHO to give ArCH 2 CHO products. This homologation protocol was used to synthesize a wide range of 2-aryl acetaldehydes with high functional group compatibility.