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 b-nitro alcohols in excellent yields and enantiomeric excesses up to 86%.
M. Bandini, S. Cabiddu, E. Cadoni, P. Olivelli, R. Sinisi, A. Umani-Ronchi, et al. (2009). New adaptive chiral thiophene ligands for copper-catalyzed asymmetric reaction. CHIRALITY, 21, 239-244 [10.1002/chir.20613].
New adaptive chiral thiophene ligands for copper-catalyzed asymmetric reaction
BANDINI, MARCO;OLIVELLI, PASQUALE;SINISI, RICCARDO;UMANI RONCHI, ACHILLE;
2009
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 b-nitro alcohols in excellent yields and enantiomeric excesses up to 86%.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
