Enantioselective transformation of hydrazones via remote NHC catalysis: activation across C=N and N−N bonds

Abstract

The catalytic asymmetric transformation of nitrogen atoms to prepare heterocyclic molecules is of significant value in organic synthesis and biological applications. Here, we disclose the activation of the nitrogen atom in hydrazine-derived hydrazone via an N-heterocyclic carbene (NHC) organic catalyst for highly enantioselective formal cycloaddition reactions. The range of NHC catalysis extends across several (carbon and hetero) atoms and diverse chemical bonds (C═N and N-N bonds) to activate nitrogen atoms at remote sites with excellent reactivity and (stereo)selectivity control. Our strategy for nitrogen atom activation, along with the NHC-bound diaza-diene intermediate generated during the catalytic process, offers alternative solutions for organic synthesis.