Isolation of Tridentate Acyclic Bis(Pyridine)carbodicarbene and Palladium Complex Further Studies on Its Structural Implications and Application

• Main Authors: Yu-Cheng Hsu, 許育晟
• Other Authors: 詹益慈
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/ku42f9

博士 === 國立臺灣大學 === 化學研究所 === 106 === The simple synthetic development of acyclic pincer bis(pyridine)carbodicarbene is depicted herein. Presented is the first isolated structural pincer carbodicarbene with a C-C-C angle of 143°, larger than the monodentate framework. More importantly theoretical analysis revealed that this carbodicarbene embodies a more allene-like character. Pd complexes supported by this pincer ligand are active catalysts for Heck-Mizoroki and Suzuki-Miyaura coupling reactions. The combination of conventional transition metal-catalyzed coupling reactions and photoredox catalysis has emerged as a powerful approach to catalyze difficult cross-coupling reactions under mild conditions (e.g. alkyl-olefin C-C and C-O bond formations). In these reactions, two distinct organometallic catalysts are necessary for promoting the catalytic photoredox and coupling sequences. Herein, we report a unique Pd complex that mediates both photoredox catalysis for C-N bond formation upon visible-light irradiation and conventional Suzuki-Miyaura coupling in the absence of light. These two catalytic pathways can be merged to promote both conventional transition-metal-catalyzed coupling and photoredox catalysis to mediate C-H arylation under ambient conditions with a single component catalyst in an efficient one-pot process. We demonstrate the potential of applying visible light to turn on a different type of cross-coupling reaction (through the excited-state scheme) in addition to the inherent ground-state catalysis using a single metal complex.