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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

Synthesis of Enantiomerically-Enriched α-Boryl Organometallic Reagents by Transition-Metal Catalysis:

Zhang, Chenlong January 2021 (has links)
Thesis advisor: James Morken / This dissertation will present two main projects focusing on the construction of enantiomerically enriched α-boryl organometallic reagents by transition metal catalysis. The first project describes the development of a platinum-catalyzed enantioselective hydrosilylation reaction of alkenyl boronic esters, which provides a general and efficient route to α-borylsilane species. Such species are configurationally stable and exhibit significant synthetic utilities. The second project depicts a nickel-catalyzed enantioselective carbozincation reaction of vinyl boronic esters, which for the first time giving approach to enantioenriched α-borylzinc reagents. These reagents possess good configurational stability at low temperatures and can participate in copper-catalyzed allylation, palladium-catalyzed Negishi cross-coupling and electrophilic halogenation reactions in stereospecific fashion to furnish a broad array of chiral boronic esters. These compounds are important and versatile building blocks in organic synthesis and utilized in the synthesis of (–)-aphanorphine and (–)-enterolactone. Detailed mechanistic studies were carried out, which revealed a nickel(I)-based redox neutral catalytic cycle. The properties of α-borylzinc compounds were also studied by 1H NMR and enabled the development of a stereoconvergent cross-coupling of racemic α-borylzinc reagents. Such catalytic system is also effective for an enantioselective silylzincation of vinyl boronic esters. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

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