19146-52-2Relevant articles and documents
Chiral Bronsted Acids Catalyze Asymmetric Additions to Substrates that Are Already Protonated: Highly Enantioselective Disulfonimide-Catalyzed Hantzsch Ester Reductions of NH-Imine Hydrochloride Salts
Wakchaure, Vijay N.,Obradors, Carla,List, Benjamin
supporting information, p. 1707 - 1712 (2020/08/28)
While imines are frequently used substrates in asymmetric Bronsted acid catalysis, their corresponding salts are generally considered unsuitable reaction partners. Such processes are challenging because they require the successful competition of a catalytic amount of a chiral anion with a stoichiometric amount of an achiral one. We now show that enantiopure disulfonimides enable the asymmetric reduction of N-H imine hydrochloride salts using Hantzsch esters as hydrogen source. Our scalable reaction delivers crystalline primary amine salts in great efficiency and enantioselectivity and the discovery suggests potential of this approach in other Bronsted acid catalyzed transformations of achiral iminium salts. Kinetic studies and acidity data suggest a bifunctional catalytic activation mode.
Rhodium-catalyzed asymmetric hydrogenation of unprotected NH imines assisted by a thiourea
Zhao, Qingyang,Wen, Jialin,Tan, Renchang,Huang, Kexuan,Metola, Pedro,Wang, Rui,Anslyn, Eric V.,Zhang, Xumu
supporting information, p. 8467 - 8470 (2014/08/18)
Asymmetric hydrogenation of unprotected NH imines catalyzed by rhodium/bis(phosphine)-thiourea provided chiral amines with up to 97% yield and 95% ee. 1HNMR studies, coupled with control experiments, implied that catalytic chloride-bound intermediates were involved in the mechanism through a dual hydrogen-bonding interaction. Deuteration experiments proved that the hydrogenation proceeded through a pathway consistent with an imine.
Stereoselective synthesis of α-arylalkylamines by glycosylation-induced asymmetric addition of organometallic compounds to imines
Allef, Petra,Kunz, Horst
experimental part, p. 646 - 652 (2009/12/26)
Activation of imines of aromatic aldehydes by N-glycosylation with O-pivaloyl-galactopyranosyl bromide (pivalobromogalactose) and subsequent addition of organotin, organolithium, Grignard, or organozinc reagents afforded α-arylalkylamines with moderate to
