New Adaptive Chiral Thiophene Ligands for Copper-Catalyzed Asymmetric Henry Reaction

Bandini M;Cabiddu S;CADONI, ENZO;Olivelli P;Sinisi R;Umani Ronchi A;USAI, MICHELE

2009-01-01

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Abstract

A new type of adaptive chiral thiophene-based ligands 3 has been designed and developed. The synthetic flexibility of the thienyl ring allowed for the preparation of polydendate C2-symmetric ligands in good yields, carrying simultaneously "hard" as well as "soft" coordinating atoms (i.e., N, S). The coordination attitude of 3 was then tested in the enantioselective base-free Cu(OAc)(2)-catalyzed addition of nitromethane to aromatic aldehydes, leading to the corresponding P-nitro alcohols in excellent yields and enantiomeric excesses up to 86%. Chirality 21:239-244, 2009. (c) 2008 Wiley-Liss, Inc.