New adaptive chiral thiophene ligands for copper-catalyzed asymmetric Henry reaction.
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 beta-nitro alcohols in excellent yields and enantiomeric excesses up to 86%.
Bandini
Marco
M
Dipartimento di Chimica G. Ciamician, Alma Mater Studiorum, University of Bologna, Bologna, Italy. marco.bandini@unibo.it
Cabiddu
Salvatore
S
Cadoni
Enzo
E
Olivelli
Pasquale
P
Sinisi
Riccardo
R
Umani-Ronchi
Achille
A
Usai
Michele
M