Metal-Free Reduction of Tertiary Amides

Charett et al. have reported a highly chemoselective metal-free process for the reduction of tertiary amides using Hantzch ester (1). According to their report, they hypothesized that treating an amide with Tf₂O would generate an iminium triflate that could be reduced to the corresponding amine using a mild reducing agent 1. As compared to the general protocol using LAH, this reaction can prevent the formation of byproducts. Furthermore, because tertiary amides containing several functional groups can be reduced selectively, it is expected that this method will apply to the synthesis of natural products, etc.