Synthesis Of Oxindoles And Tetrahydroquinolines Via Visible Light Photoredox Catalysis

This thesis depicts the author’s graduate research works which have been focused on the applications of visible light photoredox catalysis to the synthesis of N-heterocycles. It comprises three parts. In the first part, the recent progress made on applying the visible light-induced single electron transfer reactions to organic synthesis is briefly reviewed. The second part and the third part deal with the author’s own researches which are summarized as follows:(1) A novel method for the synthesis of3,3-disubstituted oxindoles from a-bromo-N-acylaniline via fac-(ppy)3Ir-mediated visible light photoredox catalysis has been developed. This protocol is suitable for the synthesis of oxindoles incorporating a bromo atom at the phenyl ring as well as the3-acetyl substituted oxindoles. These structures are generally difficult to prepare using other methods.(2) Tetrahydroquinolines have been prepared from anilines and maleimides has been realized under visible light irradiation by using Ru(bpy)3Cl2as catalyst and air as oxidant. The photochemical method is advantageous in terms of high efficiency and broad substrate scope compared with the copper-mediated protocol as reported in literature. This work serves as a new illustration that the chemistry of a-aminoalkyl radicals generated in visible light-induced electron transfer processes are of important synthetic value.