Directing the Activation of Donor-Acceptor Cyclopropanes Towards Stereoselective 1,3-Dipolar Cycloaddition Reactions by Brønsted Base Catalysis.

Autor: Blom J; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark., Vidal-Albalat A; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark., Jørgensen J; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark., Barløse CL; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark., Jessen KS; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark., Iversen MV; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark., Jørgensen KA; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000, Aarhus C, Denmark.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2017 Sep 18; Vol. 56 (39), pp. 11831-11835. Date of Electronic Publication: 2017 Aug 16.
DOI: 10.1002/anie.201706150
Abstrakt: The first stereoselective organocatalyzed [3+2] cycloaddition reaction of donor-acceptor cyclopropanes is presented. It is demonstrated that by applying an optically active bifunctional Brønsted base catalyst, racemic di-cyano cyclopropylketones can be activated to undergo a stereoselective 1,3-dipolar reaction with mono- and polysubstituted nitroolefins. The reaction affords functionalized cyclopentanes with three consecutive stereocenters in high yield and stereoselectivity. Based on the stereochemical outcome, a mechanism in which the organocatalyst activates both the donor-acceptor cyclopropane and nitroolefin is proposed. Finally, chemoselective transformations of the cycloaddition products are demonstrated.
(© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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