864445-67-0Relevant articles and documents
Bimetallic catalysis in the highly enantioselective ring-opening reactions of aziridines
Wu, Bin,Gallucci, Judith C.,Parquette, Jon R.,Rajanbabu
, p. 1102 - 1117 (2014/03/21)
Bimetallic yttrium- and lanthanide-salen complexes, readily prepared from commercially available metal isopropoxides, 2-dimethylaminoethanol, 1,1′-binaphthyl-2,2′-diamine and 2-hydroxy-3-methoxybenzaldehyde (3 steps) catalyze highly enantioselective ring opening (～90-99% ee) reactions of meso-N-4-nitrobenzoyl aziridines by TMSCN and TMSN3. The TMSN 3-mediated reactions give the highest enantioselectivities reported to date for several prototypical aziridines. Selectivity in a related ring opening by silyl isothiocyanates depends on the substituents on silicon, larger tBuPh2SiNCS giving the best selectivities, especially when an yttrium or ytterbium complex is used as the catalyst. The bimetallic yttrium complex also effects unprecedented regiodivergent parallel kinetic resolution of racemic monosubstitued aziridines upon reaction with TMSN3. In these reactions, each of the enantiomers undergoes nucleophilic addition of azide at different carbons giving two products in nearly enantiomerically pure form. To explain the dramatic differences in the selectivities between the mono- and bimetallic catalysts in these reactions, a mechanism that involves activation of both the electrophile (aziridine) and the nucleophile (azide or cyanide) at two different metals of the bimetallic complex is proposed. Molecular weight determination by vapor pressure osmometry, diffusion ordered NMR spectroscopy (DOSY) and kinetic studies, which suggest first order dependence on the concentration of the catalyst, provide strong support for this proposal. The Royal Society of Chemistry 2014.
Enantioselective desymmetrization of meso-aziridines with TMSN3 or TMSCN catalyzed by discrete yttrium complexes
Wu, Bin,Gallucci, Judith C.,Parquette, Jon R.,RajanBabu
supporting information; experimental part, p. 1126 - 1129 (2009/06/20)
(Chemical Equation Presented) Y is it so? Dimeric yttrium-salen complexes (see structure; N blue, O red, Y magenta) catalyze the highly enantioselective ring-opening of meso-aziridines by TMSCN and TMSN3. To explain the dramatic differences in
LIGAND, METHOD FOR PRODUCING THE SAME, AND CATALYST USING THE LIGAND
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Page/Page column 25-26; 27, (2009/01/20)
Disclosed is a novel asymmetric ligand which can be synthesized by a short process at low cost and is capable of exhibiting higher catalytic activity and enantioselectivity than the conventional ligands derived from sugars. Also disclosed are a method for producing such an asymmetric ligand, and a catalyst using such an asymmetric ligand. Specifically disclosed is a ligand represented by the general formula I below or the like. (In the formula, R1 and R2 independently represent 0-5 substituents; X represents P, As or N; m represents an integer of 0-7; n represents an integer of 0-3; A1-A4 independently represent hydrogen, fluorine, chlorine, bromine, benzoyl or acetyl, or alternatively A2 and A3 combine together to form a ring.)
Toward a rational design of the assembly structure of polymetallic asymmetric catalysts: design, synthesis, and evaluation of new chiral ligands for catalytic asymmetric cyanation reactions
Fujimori, Ikuo,Mita, Tsuyoshi,Maki, Keisuke,Shiro, Motoo,Sato, Akihiro,Furusho, Sanae,Kanai, Motomu,Shibasaki, Masakatsu
, p. 5820 - 5831 (2008/02/03)
New chiral ligands (4 and 5) for polymetallic asymmetric catalysts were designed based on the hypothesis that the assembled structure should be stable when made from a stable module 8. A metal-ligand=5:6+μ-oxo+OH complex was generated from Gd(OiPr)3 and 4 or 5, and this complex was an improved asymmetric catalyst for the desymmetrization of meso-aziridines with TMSCN and conjugate addition of TMSCN to α,β-unsaturated N-acylpyrroles, compared to the previously reported catalysts derived from 1-3. These two groups of catalysts produced opposing enantioselectivity even though the ligands had the same chirality. The functional difference in the asymmetric catalysts is derived from differences in the higher-order structure of the polymetallic catalysts.
Catalytic enantioselective desymmetrization of meso-N-acylaziridines with TMSCN
Mita, Tsuyoshi,Fujimori, Ikuo,Wada, Reiko,Wen, Jianfeng,Kanai, Motomu,Shibasaki, Masakatsu
, p. 11252 - 11253 (2007/10/03)
A catalytic enantioselective desymmetrization of meso-N-p-nitrobenzoylaziridines with TMSCN was developed using a chiral gadolinium catalyst generated from Gd(OiPr)3 and d-glucose-derived ligand 1. In this reaction, the addition of a
