Transition-Metal-based Lewis Acid, Base, and Ambiphilic Catalysts: Development of Non-Salt Alternative Processes

摘要

The discovery of a new chemical reaction often leads to new chemical principle and application. We found that low valent ruthenium, rhodium, iridium, and rhenium hydride complexes can be used as transition metal-based redox Lewis acid and base, and ambiphilic catalysts. Various substrates bearing alpha-hetero atom (pronucleophiles) such as nitriles, carbonyl compounds, isocyanates undergo alpha-C-H activation upon treatment with the transition-metal-based catalysts, and subsequent reaction with nucleophiles such as alkenes, alkynes, carbonyl compounds, imines, and nitriles give the products via carbon-carbon bond formations. Nitriles undergo reactions with either nucleophiles or electrophiles under neutral conditions in the presence of transition-metal-based redox Lewis acid catalysts. The catalysts can be used also as ambiphilic catalysts. With these catalysts multi-step reactions are carried out in one pot under neutral conditions, and are highly useful for combinatorial chemistry and the reactions in microreactor. The novel transition metal complex catalyzed reactions thus obtained would give various non-salt alternative processes for industry. The concept would provide an important way for green chemistry.