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Light as a Reagent for Chemical Reactions-Excited State Manipulation to Discover New Reactivity

Kandappa, Sunil Kumar
http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1573830383912829

Abstract Details

2019, Doctor of Philosophy (Ph.D.), Bowling Green State University, Photochemical Sciences.
Photochemical reactions provide a complementary strategy for the synthesis of complex organic molecules as it often involves multiple bond formation in a single step. However, use of organic photoreaction as a common tool in synthesis is limited due to challenges associated with controlling their excited state properties. Altering the molecular framework has the potential to alter their excited state features opening new reactive pathways. This requires in depth understanding of reactivity and excited state dynamics. This dissertation details an effort to engineer new excited state reactions of organic molecules. Fundamentals of organic photochemistry and various strategies that were developed in this field are discussed in the first chapter. It details concepts related to organic photoreactions and asymmetric photochemical transformations, which are known to be quite challenging due to short life time and high energetics of the reactive excited states. The chapter details various methodologies that are developed and successfully implemented for controlling photochemical reactions. Second chapter describes photocycloaddition of an excited alkene to a carbonyl group. Due to the difference in the nature of orbital that initiates the cycloaddition, the reaction was labeled as Transposed Paternò-Büchi reaction. The strategy developed in this chapter is different from normal Paternò-Büchi, where an excited state carbonyl functionality adds to a ground state alkene. In-depth investigations were carried out to decipher the excited state in the reaction pathway with a likely mechanistic rationale. Chapter three details the photocycloaddition of excited alkenes with statistical and nonstabilized imines. This newly uncovered reaction was labeled as Aza Paternò-Büchi reaction. This new reaction was deciphered using photophysical studies. The reactive modes were analyzed by detailed mechanistic investigations. Fourth chapter details entropic effects as a tool to control chemoselectvity involving intramolecular [2+2] vs [3+2]-photocycloaddition. The physical properties for entropic control were deciphered due to [2+2] and [3+2] cycloaddition.
Jayaraman Sivaguru, Ph.D. (Advisor)
Mihai Staic, Ph.D. (Other)
Malcolm Forbes, Ph.D. (Committee Member)
R. Marshall Wilson, Ph.D. (Committee Member)
317 p.
Atoms and Subatomic Particles; Chemistry; Physical Chemistry
Photocycloaddition; Imine photocycloaddition; Transposed Paterno-Buchi reaction; Aza Paterno-Buchi reaction

Recommended Citations

Citations

  • Kandappa, S. K. (2019). Light as a Reagent for Chemical Reactions-Excited State Manipulation to Discover New Reactivity [Doctoral dissertation, Bowling Green State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1573830383912829

    APA Style (7th edition)

  • Kandappa, Sunil. Light as a Reagent for Chemical Reactions-Excited State Manipulation to Discover New Reactivity. 2019. Bowling Green State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1573830383912829.

    MLA Style (8th edition)

  • Kandappa, Sunil. "Light as a Reagent for Chemical Reactions-Excited State Manipulation to Discover New Reactivity." Doctoral dissertation, Bowling Green State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1573830383912829

    Chicago Manual of Style (17th edition)

bgsu1573830383912829
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© 2019, all rights reserved.
This open access ETD is published by Bowling Green State University and OhioLINK.