Snapshots of Early-Stage Quantitative N Electrophilic Functionalization.

Electrophilic functionalization of N moieties in metal dinitrogen complexes typically initiates the catalytic synthesis of N-containing molecules directly from N. Despite intensive research in the last six decades, how to efficiently and even quantitatively convert N into diazenido and hydrazido species still poses a great challenge. In this regard, systematic and comprehensive investigations to elucidate the reaction intricacies are of profound significance. Herein, we report a kinetic dissection on the first and second electrophilic functionalization steps of a new Cr-N system with HOTf, MeOTf, and MeSiOTf. All reactions pass through fleeting diazenido intermediates and furnish long-lived final hydrazido products, and both steps are quantitative conversions at low temperatures. All of the second-order reaction rates of the first and second transformations were determined as well as the lifetimes of the intervening diazenido species. Based on these findings, we succeeded in large-scale and near-quantitative preparation of all hydrazido species.