Back Cover: Two Reaction Mechanisms via Iminium Ion Intermediates: The Different Reactivities of Diphenylprolinol Silyl Ether and Trifluoromethyl‐Substituted Diarylprolinol Silyl Ether (Chem. Eur. J. 35/2015). Issue 35 (18th August 2015)

• Record Type: Journal Article
• Authors: Gotoh, Hiroaki; Uchimaru, Tadafumi; Hayashi, Yujiro
• Is Part Of: Chemistry. Volume 21:Issue 35(2015)
• Page Start: 15527
• Page End: 15527
• Publication Date: 2015-08-18
• Subjects: asymmetric synthesis -- iminium ions -- organocatalysis -- reaction mechanisms -- silyl ethers; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201583504
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract : There are two reaction modes of α, β‐unsaturated aldehydes when using a diarylprolinol silyl ether as a catalyst—one involves a Michael‐type reaction mode and the other a Diels–Alder cycloaddition mode. As the LUMO of the iminium ion derived from trifluoromethyl‐substituted diarylprolinol silyl ether is lower than that derived from diphenylprolinol silyl ether, the former is reactive in the cycloaddition reaction. On the other hand, the generation of an iminium ion from α, β‐unsaturated aldehyde is faster in the reaction of diphenylprolinol silyl ether, leading to a Michael‐type reaction. For more details see the Full Paper by Y. Hayashi et al. onpage 12337 ff.