Switching Enantioface Selection in the Asymmetric Nitro-Mannich Reaction Using Single Chiral Bis(imidazolidine)pyridine–Metal Catalysts
Received: 07 April 2014
Accepted after revision: 01 May 2014
03 June 2014 (eFirst)
Switching enantioface selection of imines in the metal-catalyzed nitro-Mannich reaction was accomplished with the same enantiomer of diamine-derived bis(imidazolidine)pyridine (PyBidine) ligand. The (S,S)-PyBidine–CoCl2 complex catalyzed the nitro-Mannich reaction of N-Ts imines to give S-enriched adducts, while the Ni(OAc)2 complex using the same ligand catalyzed the nitro-Mannich reaction of N-Boc imines in an R-stereoselective manner.