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theses

Asymmetric hydrogenation is a significant research field in modern catalytic organic synthesis. In the past 50 years, the design of catalysts and substrates has been widely studied. A great number of phosphorus ligands for asymmetric hydrogenation have been developed. Three generations of catalysts have been reported by a number of scientists. The asymmetric hydrogenation becomes more and more efficient and applicable. High enantioselectivities and activities have been achieved. The design of substrates also makes significant progresses. Many successful examples have been reported in asymmetric hydrogenation of olefins, ketones, and imines. In chapter one, the development of phosphorus ligands is reported. The characters of phosphorus ligands are discussed and compared. Examples of representative catalysts are listed. The asymmetric hydrogenation of different substrates is also summarized and discussed. In chapter two, asymmetric hydrogenation of α-dehydroamino ketones catalyzed by a rhodium-chiral phosphorus ligand complex (up to 99% ee, 1000 TON) is reported. This reaction represents an efficient approach to chiral α-amino ketones. The reduction of α-amino ketones catalyzed by Palladium on carbon (Pd/C) leads to amphetamine precursors with quantitative yield and no significant enantioselectivity loss. In chapter three, high enantioselectivities (up to 99% ee) have been observed for the catalytic asymmetric hydrogenation of the α-ketone enol acetates. DuanPhos has been proved to be the most effective ligand for this reaction. High yield and enantioselectivity of the asymmetric hydrogenation of the α-ketone enol acetates demonstrates a feasible synthetic route to important pharmaceutical building blocks: α-hydroxy ketones. In chapter four, a series of new chiral secondary phosphine oxide (SPO) ligands are reported. Compared with traditional bisphosphine ligands, the SPO ligands are air stable, and have shorter synthetic routes. However, poor to moderate results are obtained using the new chiral SPO ligands. The study of SPO ligands still has many unsolved problems. The potential applications and challenges of SPO ligands are also discussed in chapter four.

ETD_4558

Ph.D.

Includes bibliographical references

by Tian Sun

http://hdl.rutgers.edu/1782.1/rucore10001600001.ETD.000068978

doi:10.7282/T3MW2FQ6

ETD doctoral

The author owns the copyright to this work.