Dr. Ian Tonks, University of Minnesota

Title: Ti-Catalyzed Nitrene Transfer Reactions - Strategies for Catalytically Breaking and Making N-N Bonds

Abstract:Titanium is an ideal metal for green and sustainable catalysis—it is the 2nd most earth-abundant transition metal, and the byproducts of Ti reactions (typically TiO2) are nontoxic. However, a significant challenge of utilizing early transition metals for catalytic redox processes is that they typically do not undergo facile oxidation state changes because of the thermodynamic stability of their high oxidation states. Several years ago our group discovered that Ti imidos (LnTi=NR) can catalyze oxidative nitrene transfer reactions from diazenes via a TiII/TiIV redox couple. We are using this new mode of reactivity to develop a large suite of practical synthetic methods. In this talk, our latest synthetic and mechanistic discoveries related to Ti nitrene transfer catalysis and other amination reactions will be discussed, including multicomponent N-N oxidative coupling to synthesize pyrazoles, catalytic N-N dehydrocoupling for heterocycle synthesis, and more.