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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Application of Diels-Alder reactions of 2-(N-acylamino)-1,3-dienes toward the total synthesis of stenine

Boren, Brant Clayton 17 February 2005 (has links)
Natural products continue to influence society at large as many drugs are of natural product origin. Consequently, the development and study of new chemical reactions that lead to the efficient preparation of natural products is a central goal in organic chemistry today. To this end, we have investigated the reactivity and stereoselectivity of cyclic 2-(N-acylamino)-1,3-dienes toward a total synthesis of stenine. Chapter I describes the isolation and characterization of stenine, in addition to comparing five published total syntheses of stenine. Chapter II discusses synthetic and theoretical investigations of cyclic 2-(Nacylamino)- 1,3-dienes. We have shown that vinylazepenes react with Nphenylmaleimide to afford exo cycloadducts exclusively. Previous studies of vinylpiperidenes revealed a preference for endo selectivity. We confirmed the contrasting stereoselectivity by X-ray analysis of compounds i and ii. The stereoselectivity of vinylazepenes, vinylcycloalkenes, and vinyl piperidenes in Diels-Alder reactions varies depending on the detailed structure of the diene. In collaboration with Dr. Daniel Singleton and Jennifer Hirschi, DFT calculations were utilized to study model reactions of these dienes to provide insight into controlling the stereochemistry of this class of Diels-Alder reactions. Chapter III describes the synthesis of compounds such as iv and v that were utilized in intra and intermolecular Diels-Alder approaches toward the synthesis of stenine. We demonstrated that intermediate viii could be constructed from vinyl stannane vii in ten steps via an intermolecular Diels-Alder reaction of v and dimethyl fumarate (vi). Finally, we propose a synthetic plan for the completion of stenine from advanced intermediate viii.

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