Nickel-catalyzed Suzuki-Miyaura cross-couplings to set benzylic, diaryl and triaryl all-carbon quaternary stereocenters n high enantiopurity
Date
2017
Authors
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Publisher
University of Delaware
Abstract
Over the decades, chemists have been dedicated to building quaternary carbon centers via various methods. Transition metal-catalyzed asymmetric cross-couplings have been proven to be highly efficient in synthesizing the targeted structure in high enantiomeric purity. In particular, the use of allylic electrophiles is conspicuous in this kind of reaction; however, the lack of such chemistry for non-allylic electrophiles limits the scope. ☐ In the first chapter, prior work in the preparation of all-carbon quaternary centers via catalytic reactions is discussed. Methods like enantioselective alkylation, arylation, allylation, aldol reaction, conjugate addition, and cycloaddition are introduced. ☐ The second chapter tells the contribution of our group in synthesizing all-carbon quaternary stereogenic centers in both high yields and excellent levels of stereochemical fidelity. This stereospecific, nickel-catalyzed Suzuki-Miyaura arylation of tertiary benzylic acetates with organoboron nucleophiles has been developed to deliver diaryl- and triarylalkanes with an economically and environmentally friendly catalytic system. Great tolerance of a variety of functional groups also stressed the mildness of the reaction conditions. ☐ Overall, this thesis describes the first example of synthesizing diaryl and triaryl benzylic all-carbon quaternary stereocenters in a stereospecific fashion, which is a very significant finding and provides a highly attractive entry to enantioriched benzylic quaternary centers.
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Keywords
Pure sciences, All-carbon, Cross-coupling, Diaryl and triaryl, Nickel catalyst, Quaternary stereocenters