TMSOTf-catalyzed isomerization of acetates of the Baylis-Hillman adducts, i
.e. methyl 3-acetoxy-3-aryl-2-methylenepropanoates and 3-acetoxy-3-aryl-2-m
ethylenepropanenitriles pro-viding methyl (2E)-2-(acetoxymethyl)-3-arylprop
-2-enoates and (2E)-2-(acetoxymethyl)-3-arylprop-2-enenitriles, respectivel
y, is described.