Copper catalyzed N-formylation of α-silyl-substituted tertiary N-alkylamines by air†
A site-selective method to prepare N-formyl amines efficiently that relies on the copper(I)-catalyzed oxidation of α-silyl-substituted tertiary N-alkylamines by air at room temperature is described. The oxidative protocol was shown to exhibit excellent functional group tolerance as it was applicable to a wide variety of amine substrates and a number of bioactive molecules and natural products. Moreover, it delinates a ligand- and additive-free amine oxidation process mediated by a low-cost metal salt with oxygen from air taking on the role of both the terminal oxidant and as part of the formylation reagent, which is unprecedented in copper catalysis. It also offers the first synthetic method that can selectively generate α-amino radical species as reactive intermediates from α-silylamines under non-photochemical reaction conditions.