title: Catalytic asymmetric 1,4-additions of beta-keto esters to nitroalkenes promoted by a bifunctional homobimetallic Co2-Schiff base complex.
abstract: Catalytic asymmetric 1,4-addition of beta-keto esters to nitroalkenes is described. 2.5 mol % of a homobimetallic Lewis acid/Brønsted base bifunctional Co2-Schiff base complex smoothly promoted the reaction in excellent yield (up to 99%), diastereoselectivity, and enantioselectivity (up to >30:1 dr and 98% ee). Catalyst loading was successfully reduced to 0.1 mol %. Mechanistic studies suggested that intramolecular cooperative functions of the two Co-metal centers are important for high catalytic activity and stereoselectivity.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan . smatsuna@mol.f.u-tokyo.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Furutachi
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Chen
authors.forename: Shigeki
authors.initials: S
authors.lastname: Matsunaga
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Shibasaki
mesh_terms: D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D004952:Esters / Q000737:chemistry*; D007700:Kinetics; D009574:Nitro Compounds / Q000737:chemistry*; D012545:Schiff Bases / Q000737:chemistry*
chemical_list: D004952:Esters; D009574:Nitro Compounds; D012545:Schiff Bases; D003035:Cobalt