Unique chemoselective Mukaiyama aldol reaction of silyl enol diazoacetate with aldehydes and acetals catalyzed by MgI2 etherate

Abstract

Functionalized diazo acetoacetates are prepared by an efficient Mukaiyama aldol reaction between 3-TBSO-2-diazo-3-butenoate with aldehydes and acetals under mild reaction conditions. A variety of substituted aldehydes and the corresponding acetals are both accessible in good to excellent yields through this methodology. MgI2 etherate (MgI2·(OEt2)n) is the preferred catalyst and, the addition proceeds without decomposition of the diazo moiety. In addition, this MgI2·(OEt2)n-catalyzed Mukaiyama aldol reaction shows unique chemoselectivity towards aldehydes and acetals.