87858-37-5Relevant academic research and scientific papers
Catalytic enantioselective addition of organometallic reagents to N-formylimines using monodentate phosphoramidite ligands
Pizzuti, Maria Gabriella,Minnaard, Adriaan J.,Feringa, Ben L.
, p. 940 - 947 (2008/09/18)
(Chemical Equation Presented) The asymmetric synthesis of protected amines via the copper/phosphoramidite-catalyzed addition of organozinc and organoaluminum reagents to N-acylimines, generated in situ from aromatic and aliphatic α-amidosulfones, is reported. High yields of optically active N-formyl-protected amines and enantioselectivities up to 99% were obtained. Under the reaction conditions, partial oxidation of the phosphoramidite ligand to the corresponding phosphoric amide was detected. A preliminary study on the origin and the effect on the catalytic addition reaction is presented.
Development of chiral catalysts by asymmetric activation for highly enantioselective diethylzinc addition to imines
Zhang, Hai-Le,Liu, Hua,Cui, Xin,Mi, Ai-Qiao,Jiang, Yao-Zhong,Gong, Liu-Zhu
, p. 615 - 618 (2007/10/03)
Based on the asymmetric activation concept, a library of chiral zinc complexes in situ formed by the combination of diimines derived from chiral 1,2-diphenyl-ethanene-1,2-diamine, BINOL derivatives, and diethylzinc are evaluated in the asymmetric addition of diethylzinc to N-acylimines. In the presence of 10 mol% L3ZnA1, high enantioselectivities and yields were provided for a wide range of aromatic imines in 1,2-dichloroethane at -25 °C.
Discovery of chiral catalysts by asymmetric activation for highly enantioselective diethylzinc addition to imines: Using racemic and achiral diimines as effective activators
Liu, Hua,Zhang, Hai-Le,Wang, Shuang-Jun,Mi, Ai-Qiao,Jiang, Yao-Zhong,Gong, Liu-Zhu
, p. 2901 - 2907 (2007/10/03)
A library of chiral zinc complexes formed in situ by the combination of achiral and racemic diimines with 3,3′-di(3,5-ditrifluoromethylphenyl)- BINOL and diethylzinc were evaluated in the asymmetric addition of diethylzinc to N-acylimines. In the presence of 10 mol % of chiral ligand 4 and racemic diimine 5, high enantioselectivities of up to 97% ee and yields of up to 96% were achieved for a wide range of aromatic imines in dichloromethane at -30°C.
The asymmetric dialkylzinc addition to imines catalyzed by [2.2]paracyclophane-based N,O-ligands
Dahment, Stefan,Braese, Stefan
, p. 5940 - 5941 (2007/10/03)
The first highly enantioselective dialkylzinc addition to imines in the presence of catalytic amounts of N,O-ligands is reported. N-formyl-α-(p-tolysulfonyl)benzylamines are the readily available starting materials easily obtained in a one-pot synthesis from benzaldehydes, formamide, and p-tolylsulfinic acid. Upon deprotonation, the sulfinate is eliminated to give the acyl imine. The acyl imines further react with alkylzinc reagents in the presence of catalytic amounts of [2.2]paracyclophane-based N,O-ligands L* yielding the alkylated N-(1-phenylpropyl)formamides with excellent yields and enantioselectivities. Copyright
A Chiral Recognition Model for the Chromatographic Resolution of N-Acylated 1-Aryl-1-aminoalkanes
Pirkle, William H.,Welch, Christopher J.,Hyun, Myung Ho
, p. 5022 - 5026 (2007/10/02)
The enantiomers of N-acyl derivatives of 1-aryl-1-aminoalkanes generally may be chromatographically separated on a silica-bonded chiral stationary phase derived from N-(3,5-dinitrobenzoyl)phenylglycine.Chiral recognition is enhanced by increases in either the ? basicity of the aryl substituent or the size of the alkyl substituent but is diminished by increases in the size of the acyl group.Carbamate and urea derivatives of these amines are also resolvable.Chiral recognition models are proposed to account for the observed chiral recognition and are used to assign absolute configuration to several acylated amines.
