Stereospecific, nickel-catalyzed cross-couplings of amine and alcohol derived substrates

Author(s)Cobb, Kelsey M.
Date Accessioned2017-12-15T12:37:52Z
Date Available2017-12-15T12:37:52Z
Publication Date2017
SWORD Update2017-09-05T16:33:05Z
AbstractThis dissertation focuses on nickel-catalyzed cross-couplings of amine and alcohol derivatives to set stereogenic centers. Chapter 1 focuses on the cross-coupling of benzylic ammonium triflates with aryl, heteroaryl, and vinyl boronic acids. This method expands the scope of previous methods from our group, utilizing Ni(cod)2 without any additional phosphine or N-heterocyclic carbene (NHC) ligands. This reaction allows for cross-coupling of both naphthyl and phenyl substituted ammonium salts. The mild conditions of this reaction displays excellent functional group tolerance. ☐ Chapter 2 focuses on the cross-coupling of benzylic ammonium triflates with bis(pinacolato)diboron to afford secondary benzylic boronates with excellent chirality transfer, This reaction utilizes Ni(cod)2 as a catalyst with either phosphine or NHC ligands. The reaction proceeds with mild reaction conditions and excellent functional group tolerance. It allows for the cross-coupling of both naphthyl and phenyl substituted ammonium salts. This is the first example of a Miyaura borylation of a non-allylic electrophile to deliver products in highly enantioenriched form. ☐ Chapter 3 describes the development of the cross-coupling of tertiary benzylic acetates to form all-carbon quaternary stereocenters. This reaction prioritizes the use of an air-stable nickel(II) catalyst and environmentally friendly 2-Me-THF. The mild reaction conditions allow for excellent functional group tolerance. The reaction provides an efficient route to both di-aryl and tri-aryl quaternary stereocenters in high stereochemical fidelity. This method shows an expansion in transition metal catalysis to go beyond electrophiles adjacent to functional groups such as carbonyls and alkenes, and displays the possibility for tertiary benzylic electrophiles to under go transition metal catalysis. ☐ Chapter 4 focuses on the cross-coupling of enantioenriched allylic pivalates with aryl and heteroaryl borxines to form allylic, all-carbon quaternary stereocenters. This utilizes an air-stable nickel (II) catalyst, and functional group tolerant boroxine coupling partners to afford these quaternary stereocenters with high stereochemical fidelity. This reaction provides a powerful way to readily access allylic quaternary stereocenters with substituted internal alkenes and a variety of functional groups and heteroatoms in high yield and enantioenrichmenten_US
AdvisorWatson, Mary P.
DegreePh.D.
DepartmentUniversity of Delaware, Department of Chemistry and Biochemistry
Unique Identifier1015370539
URLhttp://udspace.udel.edu/handle/19716/21815
Languageen
PublisherUniversity of Delawareen_US
URIhttps://search.proquest.com/docview/1958944696?accountid=10457
KeywordsPure sciencesen_US
KeywordsBenzylic ammonium triflatesen_US
KeywordsEnantioenriched benzylic boronatesen_US
KeywordsN-heterocyclic carbeneen_US
TitleStereospecific, nickel-catalyzed cross-couplings of amine and alcohol derived substratesen_US
TypeThesisen_US
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