Oxidation of the inert sp3 C–H bonds of tetrahydroisoquinolines through C–H activation relay (CHAR): construction of functionalized isoquinolin-1-ones

Abstract

A TBN/O₂-initiated oxidation of the relatively inert 3,4-C–H bonds of THIQs was accomplished, in which the existence of an α-phosphoric ester group is crucial to enable dioxygen trapping and intramolecular HAT (C–H activation relay, CHAR), realizing the synthesis of a series of isoquinolin-1-ones in high yields. The mechanistic study confirmed that the formation of the 3,4-double bond is mediated by the CHAR process. This work provides a new strategy to achieve remote C–H bond activation.