New Auxiliaries for Copper??Catalyzed Asymmetric Michael Reactions: Generation of Quaternary Stereocenters at Room Temperature

J Christoffers, A Mann

Index: Christoffers, Jens; Mann, Alexander Chemistry - A European Journal, 2001 , vol. 7, # 5 p. 1014 - 1027

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Citation Number: 57

Abstract

Abstract Dialkyl amides of l-valine, l-isoleucine, and L-tert-leucine (2) are excellent chiral auxiliaries for the construction of quaternary stereocenters at ambient temperature. Enaminoesters 3, prepared from these auxiliaries 2 and Michael donors 1, undergo a copper-catalyzed asymmetric Michael reaction with methyl vinyl ketone (MVK, 4) to afford products 5 in 70–90% yield and 90–99% ee (enantiomeric excess). The exclusion of ...