Oxidants Controlled C−H Bond Functionalization of N‐Aryltetrahydroisoquinolines: The Construction of the Quaternary Carbon Center and Cleavage of the C−N Bond

Initiated by triarylamine radical cation salt (TBPA), the direct C−H bond functionalization of α‐N‐aryltetrahydroisoquinoline esters was smoothly realized, giving a series of α‐hydroxylated derivatives with a quaternary carbon center in good yields. Differently, in the presence of tert‐butyl nitrite (TBN), the C−N single bond was cleaved to keto esters. The mechanistic study revealed that these reactions were mediated by a similar mechanism, in which the N‐nitrosation might provide a driving force to the C−N bond cleavage. A C−H functionalization of α‐THIQ esters was achieved by triarylamine radical cation salt and tert‐butyl nitrite, respectively, providing a series of α‐hydroxy THIQ esters and N‐NO skeleton containing keto esters under mild reaction conditions.