In 2004, we reported a procedure for making 3-hydroxyacrylate 7 from ethyl diazoacetate and benzaldehyde (6) in excellent yield using HBF 4 ·OEt 2 as a catalyst (Scheme [1] ). [4] During our studies with substituted benzaldehydes to prepare substituted 3-hydroxyacrylates, we reacted salicylaldehyde (1a) with ethyl diazoacetate in the presence of HBF 4 ·OEt 2 . The reaction did not produce any acrylate 8, rather 20% of 3-ethoxycarbonylbenzofuran (2a) was isolated ...
