Catalytic Reactions of Chiral Guanidines and Guanidinium Salts

Chiral guanidines have been widely used as Brønsted base catalysts and phase transfer catalysts in enantioselectiver eactions. Due to their amendable structure and powerful catalytic ability,t hey have attracted much interest. Several new catalysts containing ag uanidinium moiety have been reported over the past decade and many promising outcomes have been achieved. This article illustrates the progress of chiral guanidine catalysis in asymmetric synthesis from 2009t o2 018. It is an update of ar eview of the same titlepublished in 2009. [4b] [a]

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Structural considerations for charge‐enhanced Brønsted acid catalysts

Payne

Kass

2020

J of Physical Organic Chem

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All three N-methylated and N-protonated hydroxypyridinium BAr F 4 salt isomers were synthesized and their hydrogen bond donating abilities were investigated. DFT and G4 theory computations along with IR spectroscopic measurements were found to be effective methods for predicting the catalytic activities of these O-H and N-H Brønsted acids. A UV-vis titration approach for rapidly quantifying hydrogen bond donating ability revealed that carbonhydrogen bonds also can participate in electrostatic interactions, but the presence of multiple equilibrium complexes results in a limitation of this method. In the methylated series of hydroxypyridines, the ortho and para isomers displayed modest rate enhancements relative to the meta derivative. Protonation introduces a new acidic site and the ortho hydroxypyridinium ion This article is protected by copyright. All rights reserved. This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

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Catalytic Reactions of Chiral Guanidines and Guanidinium Salts

Abstract: This account chronicles our discovery and development of catalytic reactions using chiral guanidines and guanidinium salts.

Cited by 26 publications

References 34 publications

Asymmetric Base Organocatalysis

Asymmetric Base Organocatalysis

Recent Advances in Chiral Guanidine‐Catalyzed Enantioselective Reactions

Structural considerations for charge‐enhanced Brønsted acid catalysts

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