In Situ Catalyst Generation and Benchtop-Compatible Entry Points for TiII/TiIV Redox Catalytic Reactions

The development of several in situ generated catalyst systems for Ti-catalyzed oxidative nitrene transfer reactions is reported. The simplest and widely applicable catalyst system, TiCl4(THF)2/Zn0, can be set up on the benchtop under air. This system uses commercially available reagents and can be used as an entry point for TiII/TiIV multicomponent redox reactions for the synthesis of pyrroles, α,γ-unsaturated imines, α,β-unsaturated imines, cyclopropylimines, and arenes.