Novel Powerful N-Formylating Reagent

N-Formylsaccharin (1), which was developed by Cossy et al., is a novel powerful formylating reagent. Several methods or reagents for the N-formylation of amines, for example, the method using formic acid in the presence of an activating reagent such as DCC, or paraformaldehyde, have been reported. However, these methods are often lacking generality, or need heating reaction conditions. The use of 1 makes it possible to formylate amines under mild conditions. In particular, the selective N-formylation proceeds in the case of using amino alcohols as substrates.