2026-09-20T06:59:38Zhttps://dspace.mit.edu/server/oai/request

oai:dspace.mit.edu:1721.1/397412022-01-13T07:54:21Zcom_1721.1_7582com_1721.1_7581col_1721.1_131022

Gregory C. Fu. Lee, Elaine C Massachusetts Institute of Technology. Dept. of Chemistry. Massachusetts Institute of Technology. Department of Chemistry 2007-12-07T16:16:53Z 2007-12-07T16:16:53Z 2007 2007 http://hdl.handle.net/1721.1/39741 181376081 Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007. Vita. Includes bibliographical references. The development of an improved synthesis of nucleophilic planar-chiral catalysts is described in Chapter 1. This route is amenable to scale-up and preparative chiral HPLC is unnecessary to resolve the racemic catalysts. Using planar-chiral catalysts, two synthetic methodology projects have been developed: Chapter 2 describes the first asymmetric synthesis of trans P-lactams, and Chapter 3 describes the asymmetric synthesis of tertiary a-chloroesters. In the chapter describing the asymmetric synthesis of trans [beta]-lactams, we present mechanistic data supporting a novel mechanism, in which the N-triflylimine, rather than the ketene, reacts with the catalyst first. In the chapter describing the asymmetric synthesis of tertiary a-chloroesters, we introduced an under-utilized commercially available chlorinating reagent (2,2,6,6-tetrachlorocyclohexanone). Finally, in chapter 4, the Cu-catalyzed asymmetric synthesis of [alpha]-aminoesters via an N-H insertion is described. We have demonstrated that carbamates such as BocNH2 and CbzNH2 are efficient coupling partners in reactions with a-diazoesters to generate highly useful Boc- or Cbz-protected a-aminoesters. by Elaine C. Lee. Ph.D. 215 p. eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Chemistry. Improved synthesis and application of planar-chiral nucleophilic catalysts in asymmetric reactions and copper-catalyzed enantioselective N-H insertion reactions Copper-catalyzed enantioselective N-H insertion reactions Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="6f69698a-be0e-429c-b459-198d21cca742"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Improved synthesis and application of planar-chiral nucleophilic catalysts in asymmetric reactions and copper-catalyzed enantioselective N-H insertion reactions</Title> <Subtitle>Copper-catalyzed enantioselective N-H insertion reactions</Subtitle> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2007</PublicationDate> <Authors> <Author> <DisplayName>Lee, Elaine C</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Chemistry.</Keyword> <Abstract>The development of an improved synthesis of nucleophilic planar-chiral catalysts is described in Chapter 1. This route is amenable to scale-up and preparative chiral HPLC is unnecessary to resolve the racemic catalysts. Using planar-chiral catalysts, two synthetic methodology projects have been developed: Chapter 2 describes the first asymmetric synthesis of trans P-lactams, and Chapter 3 describes the asymmetric synthesis of tertiary a-chloroesters. In the chapter describing the asymmetric synthesis of trans [beta]-lactams, we present mechanistic data supporting a novel mechanism, in which the N-triflylimine, rather than the ketene, reacts with the catalyst first. In the chapter describing the asymmetric synthesis of tertiary a-chloroesters, we introduced an under-utilized commercially available chlorinating reagent (2,2,6,6-tetrachlorocyclohexanone). Finally, in chapter 4, the Cu-catalyzed asymmetric synthesis of [alpha]-aminoesters via an N-H insertion is described. We have demonstrated that carbamates such as BocNH2 and CbzNH2 are efficient coupling partners in reactions with a-diazoesters to generate highly useful Boc- or Cbz-protected a-aminoesters.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>