Asymmetric Cooperative Catalysis of Strong Brønsted Acid–Promoted Reactions Using Chiral Ureas
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- 19 February 2010
- journal article
- other
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 327 (5968) , 986-990
- https://doi.org/10.1126/science.1182826
Abstract
Acid Assistance: Protons are quite versatile catalysts of organic reactions, but because they are achiral, they cannot induce stereoselectivity on their own. One productive way around this problem has been to use chiral conjugate bases and perform reactions in media where the bases remain tightly attracted to protonated substrates. Xu et al. (p. 986 ; see the Perspective by Schreiner ) thoroughly explored the mechanism of an alternative approach, in which an achiral acid was used in conjunction with a second, chiral molecule (a urea derivative) for catalysis. High selectivity was attained with this method in the coupling of aryl imines with olefins. Extensive kinetic and computational studies showed that the acid and its chiral partner acted cooperatively in binding the substrates, optimizing the tradeoff between speed and selectivity.Keywords
This publication has 31 references indexed in Scilit:
- (Thio)urea organocatalysis—What can be learnt from anion recognition?Chemical Society Reviews, 2009
- Weak Brønsted Acid−Thiourea Co-catalysis: Enantioselective, Catalytic Protio-Pictet−Spengler ReactionsOrganic Letters, 2009
- Cooperative Brønsted Acid-Type Organocatalysis: Alcoholysis of Styrene OxidesOrganic Letters, 2008
- Enantioselective Mannich‐Type Reaction Catalyzed by a Chiral Brønsted AcidAngewandte Chemie International Edition in English, 2004
- A three-component coupling protocol for the synthesis of substituted hexahydropyrrolo[3,2-c]quinolinesChemical Communications, 1999
- NMR Spectroscopic Evidence for the Structure of Iminium Ion PairsJournal of the American Chemical Society, 1997
- Structure and wavelength modification in retinylidene iminium saltsCanadian Journal of Chemistry, 1996
- Lewis Acid Assisted Chiral Bronsted Acid for Enantioselective Protonation of Silyl Enol Ethers and Ketene Bis(trialkylsilyl) AcetalsJournal of the American Chemical Society, 1994
- Mechanism of Electrochemical Pinacolization. The First Asymmetric Synthesis in a Chiral MediumAngewandte Chemie International Edition in English, 1975
- Proton Transfer, Acid‐Base Catalysis, and Enzymatic Hydrolysis. Part I: ELEMENTARY PROCESSESAngewandte Chemie International Edition in English, 1964