Mechanistic Investigations into the Olefination of Oximes and Hydrazones Support Intermediate Ruthenium Nitrides

The olefination of oximes and hydrazones with ruthenium alkylidenes has recently been developed by matching substrate/metal orbital energy and polarization. We herein report detailed mechanistic investigations showing that the reaction pathway is distinct from previously established olefin-olefin metathesis reactions. The ruthenium alkylidene-mediated metathesis of olefins and hydrazones or oximes proceeds via a pathway that form intermediate ruthenium nitrides, which undergo subsequent bimolecular extrusion of molecular nitrogen. Detailed insights into the controlling features of this transformation presented herein are key to the development of future catalytic protocols for the olefination of oximes and hydrazones.