Enantioselective Conjugate Azidation of α,β-Unsaturated Ketones under Bifunctional Organocatalysis by Direct Activation of TMSN3

An enantioselective organocatalytic conjugate azidation of alpha,beta-unsaturated ketones is presented. A bifunctional organocatalyst activates TMSN3, triggering the nucleophilic addition of the azido group to enones in absence of external promoters and avoiding the direct use or the pre-formation of highly toxic and explosive hydrazoic acid. This protocol proceeds with excellent enantiocontrol under mild conditions. DFT calculations and mechanistic trials have been performed in order to demonstrate the direct activation performed by the bifunctional organocatalyst.