TEMPO Electrochemical Oxidation C-H Bond Activation And Functionalization

As a green synthetic means, electrochemical synthesis has getting more andmore attention. C-H bond is widely consisted in organic compounds, its directactivation and functionalization has become the focus of current research. This paperhas combined the two with a nitroxide TEMPO as a electro-catalyst, to achieve theelectrochemical oxidize activation and functionalization of C-H bond, and provided anew idea for the directly activation and functionalization of C-H bond.The paper includes the following two parts:1. The electrochemical oxidative functionalization of tetrahydroisoquinoline,isochroman and xanthene, mediated by a dual bromide ion/TEMPO redox catalystsystem in a two-phase electrolytic medium, has been taken andtetrahydroisoquinoline ketone, isochroman ketones and xanthones were obtained. Itwas fond that, TEMPO could selectively electrocatalytic activate C-H bond ortho to aheteroatom, provided a activated imine salt, which could react with water to give thehydroformylation product. This method requires a catalytic amount of TEMPO,without additional oxidant, provides a good idea for organic synthesis.2. On the basis of these findings, a further investigation of the possibility ofintermolecular tetrahydroisoquinoline derivatives react with other nucleophiles andintramolecular coupling reaction in the electro-catalytic oxidation conditions wasconducted. In0.1M LiClO4/CH3CN, tetrahydroisoquinoline derivatives1a reactedwith malononitrile to give the intermolecular coupling product7i; takentetrahydroisoquinoline derivatives8a as the materials for intramolecular ring closurereaction, after the reaction, imine salt10a was get.10a is an important intermediateof the ring-closing reaction, it’s generation illustrates that this idea is feasible.