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 alpha-N-aryltetrahydroisoquinoline esters was smoothly realized, giving a series of alpha-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 alpha-THIQ esters was achieved by triarylamine radical cation salt and tert-butyl nitrite, respectively, providing a series of alpha-hydroxy THIQ esters and N-NO skeleton containing keto esters under mild reaction conditions.image