Enantioselective 1, 3??Dipolar Cycloaddition of Nitrones with Ethyl Vinyl Ether: The Difference between Brønsted and Lewis Acid Catalysis

…, D Nakashima, H Yamamoto

Index: Jiao, Peng; Nakashima, Daisuke; Yamamoto, Hisashi Angewandte Chemie - International Edition, 2008 , vol. 47, # 13 p. 2411 - 2413

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Citation Number: 136

Abstract

Chiral Brønsted acid catalysis has recently become attractive because of its wide application in various asymmetric syntheses.[1] Among these catalysts, chiral phosphoric acids represent an outstanding example.[2] Whereas phosphoric acids are used to activate imine type compounds, we reported the first preparation of chiral N-triflyl phosphoramide 1a (Scheme 1, Table 1) and its utility in activating a carbonyl group in the asymmetric Diels– ...