Doctoral Dissertations

Author

Anshika Kalra

Abstract

"We present a family of anionic Mn(II) reagents supported by trisphenylamido- amlne frameworks that offer guidance with regards to ligand selection for developing C—N bond construction methodologies (extensively used in the synthesis of petrochemicals, household chemicals) through nitrene- transfer chemistry. We subsequently extend the study to include the corresponding Fe(II), Co(II), and Ni(II) reagents, to gain insights in their comparative reactivity/selectivity patterns. Attenuated levels of electrophilicity of anionic complexes proved to be more suitable for discriminating aromatic from aliphatic olefins for aziridination purposes, especially for Mn(II) complexes. However, in the case of Co(II) reagents, we observe that additional stereoelectronic parameters can occasionally override the electron-affinity of the metal nitrene as the sole guiding force, which is established as the dominant factor for Mn(II) complexes. We conclude from experimental and computational investigations that carboradical intermediates are generated by initial rate-determining nitrene-addition to one of the olefinic carbons followed by fast ring closure to form the aziridine, with rates that largely depend on the ligand and metal choice.

This study was extended to start exploring intermolecular aziridinations of alkenes catalyzed by metal reagents (Cu, Ag) supported by the rigid cyclic guanidinyl arms possessing chiral elements. In this study, we synthesized a series of cyclic chiral guanidinyl precursors and corresponding metal regents which proved to have good reactivity, but still modest enantioselectivities, in the aziridination of styrenes"--Abstract, page iv.

Advisor(s)

Stavropoulos, Pericles

Committee Member(s)

Sotiriou-Leventis, Chariklia
Choudhury, Amitava
Reddy, Prakash
Mormile, Melanie R.

Department(s)

Chemistry

Degree Name

Ph. D. in Chemistry

Comments

This work was generously supported by the National Institute of General Medical Sciences of the National Institutes of Health under Award Number R15GM117508 (to P.S.), and in part by the National Science Foundation through grant CHE-0412959 (to P.S.). The authors also thank the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences for support of this research via grant DE-FG02-03ER15387 (to T.R.C.). The authors further acknowledge the National Science Foundation for their support of the UNT Chemistry CASCaM high performance computing facility through grant CHE-1531468. The authors also thank the Special Account of Research Grants of the National and Kapodistrian University of Athens for partial support.

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2021

Journal article titles appearing in thesis/dissertation

  • Comparative nitrene-transfer chemistry to olefinic substrates mediated by a library of anionic Mn(II) triphenylamido-amine reagents and m(ii) congeners (M = Fe, Co, Ni) favoring aromatic over aliphatic alkenes
  • Is the electrophilicity of the metal nitrene the sole predictor of metal-mediated nitrene transfer to olefins? Secondary contributing factors as revealed by a library of high-spin Co(II) reagents
  • Studies directed towards the intermolecular aziridination of alkenes catalyzed by metal reagents (Cu, Ag) supported by bulky ligands with a chiral framework

Pagination

xviii, 358 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2021 Anshika Kalra, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11903

Included in

Chemistry Commons

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