Issue 2, 2015

Structure–activity relationship studies of cyclopropenimines as enantioselective Brønsted base catalysts

Abstract

We recently demonstrated that chiral cyclopropenimines are viable Brønsted base catalysts in enantioselective Michael and Mannich reactions. Herein, we describe a series of structure–activity relationship studies that provide an enhanced understanding of the effectiveness of certain cyclopropenimines as enantioselective Brønsted base catalysts. These studies underscore the crucial importance of dicyclohexylamino substituents in mediating both reaction rate and enantioselectivity. In addition, an unusual catalyst CH⋯O interaction, which provides both ground state and transition state organization, is discussed. Cyclopropenimine stability studies have led to the identification of new catalysts with greatly improved stability. Finally, additional demonstrations of substrate scope and current limitations are provided herein.

Graphical abstract: Structure–activity relationship studies of cyclopropenimines as enantioselective Brønsted base catalysts

Supplementary files

Article information

Article type
Edge Article
Submitted
07 Aug 2014
Accepted
19 Nov 2014
First published
19 Dec 2014
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2015,6, 1537-1547

Author version available

Structure–activity relationship studies of cyclopropenimines as enantioselective Brønsted base catalysts

J. S. Bandar, A. Barthelme, A. Y. Mazori and T. H. Lambert, Chem. Sci., 2015, 6, 1537 DOI: 10.1039/C4SC02402H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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