Fluoride-catalyzed aldol reaction of ethyl trimethylsilyldiazoacetate withaldehydes leading to ethyl alpha-diazo-beta-hydroxy esters and rhodium catalyzed decarboxylative rearrangement of diazo urethanes leading to beta-amino acrylates

Ethyl trimethylsilyldiazoacetate reacts smoothly with a variety of aldehyde s at 0 degrees C in the presence of a catalytic amount of tetrabutylammoniu m fluoride to produce alpha-diazo-beta-hydroxy esters in good to excellent yields. The resulting alpha-diazo-beta-hydroxy esters can be,stereoselectiv ely transformed, by a sequence of carbamation with p-toluenesulfonyl isocya nate and rhodium(II)-induced decarboxylative rearrangement, to alpha- or be ta-substituted beta-(p-toluenesulfonylamino)acrylates depending upon migrat ion aptitude of the substituents derived from the aldehydes. (C) 1999 Elsev ier Science Ltd. All rights reserved.