[reaction: see text] beta-Isocupreidine (beta-ICD)-catalyzed asymmetric Baylis-Hillman reactions of aromatic imines with 1,1,1,3,3,3-hexafluoroisopropyl acrylate (HFIPA) give (S)-enriched N-protected-alpha-methylene-beta-amino acid esters. In contrast to the corresponding aldehydes, imines show the opposite enantioselectivity. A mechanistic proposal governed by hydrogen bonding is presented.

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Enantioselective syntheses Enantioselective syntheses O 0031β-Isocupreidine-Catalyzed Asymmetric Baylis-Hillman Reaction of Imines. -The title reaction of imines (I) as well as N-benzoyl, N-mesyl, and N-tosyl analogues of (Ia), with activated alkene (II) gives (S)-enriched N-protected-α-methylene-β-amino acid esters. The highest enantioselectivities are obtained with (I). In contrast to the corresponding aldehydes which afford (R)-selectivity as was previously reported, the imines show opposite enantioselectivity. The synthetic utility of this method is demonstrated by conversion of product (IIIa) into β-lactam (V). -(KAWAHARA, S.; NAKANO, A.; ESUMI, T.; IWABUCHI, Y.; HATAKEYAMA*, S.; Org. Lett. 5 (2003) 17, 3103-3105; Grad. Sch. Biomed. Sci., Nagasaki Univ., Nagasaki 852, Japan; Eng.) -Klein 52-035

Hydroxycarboxylic acids (ether carboxylic acids) and esters Q 0450 β-Isocupreidine-Hexafluoroisopropyl Acrylate Method for Asymmetric Baylis-Hillman Reactions. -The title reaction affords the products in higher yields and enantioselectivities when the catalyst is azeotropically dried. -(NAKANO, A.; KAWAHARA, S.; AKAMATSU, S.; MOROKUMA, K.; NAKATANI, M.; IWABUCHI, Y.; TAKAHASHI, K.; ISHIHARA, J.; HATAKEYAMA*, S.; Tetrahedron 62 (2006) 2-3, 381-389; Grad. Sch. Biomed. Sci., Nagasaki Univ., Nagasaki 852, Japan; Eng.) -Y. Steudel 21-089