Redox Cycling with Tellurium. Si-H Bond Activation by a Lewis Superacidic Tellurenyl Cation

The C,N-chelated aryltellurenyl triflate [2-(tBuNCH)C₆H₄Te][OTf] (1) activates the Si-H bonds in the tertiary silanes R₃SiH via umpolung of H^- to H⁺ to give rise to the iminium salts (tBuN(H)CH)C₆H₄TeSiR₃][OTf] (2^R, R=Et, Ph (elusive) and R=Si(CH₃)₃ isolated; OTf=O₃SCF₃) comprising Te-Si bonds, which are capable of generating silyl triflates, R₃SiOTf, under attack of a second equivalent of 1. The unprecedented Si-H activation was utilized in main group redox catalysis using p-quinones, which were converted into (silylated) hydroquinones.