Te(II)/Te(IV) Mediated C–N Bond Formation on 2,5-Diphenyltellurophene and a Reassignment of the Product from the Reaction of PhI(OAc)2 with 2 TMS-OTf

We report a novel C–H to C–N bond metathesis at the 3-position of 1,2-diphenyltellurophene via oxidation of the Te­(II) center to Te­(IV) using the I­(III) oxidant [PhI­(4-DMAP)2]2+. Spontaneous reduction of a transient Te­(IV) coordination compound to Te­(II) generates an electrophilic equivalent of 4-DMAP that substitutes at a C–H bond at the 3-position of the tellurophene. Theoretical and synthetic reaction pathway studies confirm that a Te­(IV) coordination complex with 4-DMAP is an intermediate. In the course of these pathway studies, it was also found that the identity of the I­(III) oxidant generated from PhI­(OAc)2 and 2 TMS-OTf is PhI­(OAc)­(OTf) and not PhI­(OTf)2, as had been previously thought.