Desymmetrilizing Organic Molecules via Structural Functionalization

Desymmetrization is defined as the conversion of symmetric structures into non-symmetric ones under convenient reactions conditions; it can lead to asymmetric synthesis of chiral products that attracted much attention in research labs and pharmaceutical industry. Particularly, those associated with asymmetric catalysis are actively pursued and published in nearly all organic related journals widely. Obviously, desymmetrization chemistry can serve as powerful tools for many important synthesis processes. Those reactions that benefited from desymmetrization include organocatalytic desymmetrization of meso-aziridines, desymmetrization of meso-glutaric anhydrides catalyzed by Ni2-Schiff bases, asymmetric amination of selected prochiral ketones, selective diester hydrolysis, selective oxidation of diols and triol, etc. This master thesis will be mainly focused mono hydrolysis of diesters and mono oxidation of dialdehydes as well as their monitoring by using HPLC technique. The synthesis of dialdehydes was also carried out under modified conditions to give good yields. The resulting mono controlled products are very useful for organic synthesis and for pharmaceutical industry. The related mechanisms have bee discussed systematically under different conditions. In the meanwhile, the design and synthesis of new chiral phase-transfer-catalysts were performed. In these days, asymmetric catalyses have been among the most interesting and active research areas in organic and pharmaceutical sciences because chiral centers exist in numerous drugs and related materials. Chiral phase-transfer-catalysis (PTC) has been successfully employed for many asymmetric reactions, particularly, those for synthesis of amino acid derivatives and has been recognized as a practical methodology for organic synthesis due to its operational simplicity, high yield process, mild reaction conditions, use of safe and inexpensive reagents and solvents, safety considerations, environmental concerns, and possibility to conduct reactions on large scale. This master thesis will present the synthesis of key precursors to new chiral phase-transfer-catalyts by using chiral N-phosphonyl imines.

Name thesis:degree_name

Master of Science

Grantor

Texas Tech University

Year dc:date.issued

2012

Author dc:creator

• Luan, Yingying

Handle dc:identifier.uri

https://hdl.handle.net/2346/106618

OAI identifier oai:identifier

oai:ttu-ir.tdl.org:2346/106618