39648-71-0Relevant academic research and scientific papers
Enantioselective vinylation of aldehydes with the vinyl Grignard reagent catalyzed by magnesium complex of chiral BINOLs
Wang, Pei,Ma, Guo-Rong,Yu, Sheng-Li,Da, Chao-Shan
supporting information, p. 79 - 86 (2018/12/13)
Enantioselective vinylation of aldehydes via direct catalytic asymmetric Grignard reaction of aldehdyes and the vinyl Grinard reagent is a long-standing challenge. This work demonstrated that the magnesium (S)-3,3′-dimethyl BINOLate enantioselectively catalyze the direct vinylation of aldehydes with the deactivated vinylmagnesium bromide by bis(2-[N,N′-dimethylamino]ethyl) ether (BDMAEE) in the addition of n-butylmagnesium chloride. The highest ee of 63% was achieved up to date.
An enantioselective oxidative coupling reaction of 2-naphthol derivatives catalyzed by chiral diphosphine oxide-iron(ii) complexes
Horibe, Takahiro,Nakagawa, Keita,Hazeyama, Takashi,Takeda, Kazuki,Ishihara, Kazuaki
supporting information, p. 13677 - 13680 (2019/11/19)
An enantioselective oxidative coupling of 2-naphthol derivatives is developed with the use of chiral Fe(ii)-diphosphine oxide complexes. Optically active 1,1-bi-2-naphthol derivatives can be synthesized in high yields when a 2?:?1 complex of (S)-xylyl-iPrO-BIPHEP-oxide and Fe(OTf)2 is used in the presence of t-butyl hydroperoxide as an oxidant. The non-linear effect, X-ray crystal structure and ESI-MS suggest that a 2?:?1 complex of (S)-xylyl-iPrO-BIPHEP-oxide and Fe(OTf)2 is a pre-catalyst for a Fe(iii)/Fe(iv) redox cycle.
Direct asymmetric reductive amination for the synthesis of (S)-rivastigmine
Gao, Guorui,Du, Shaozhi,Yang, Yang,Lei, Xue,Huang, Haizhou,Chang, Mingxin
supporting information, (2018/09/10)
In this article we demonstrate how asymmetric total synthesis of (S)-rivastigmine has been achieved using direct asymmetric reductive amination as the key transformation in four steps. The route started with readily available and cheap m-hydroxyacetophenone, through esterification, asymmetric reductive amination, N-diphenylmethyl deprotection and reductive amination, to provide the final (S)-rivastigmine in 82% overall yield and 96% enantioselectivity. In the asymmetric reductive amination, catalysed by the iridium–phosphoramidite ligand complex and helped by some additives, the readily prepared 3-acetylphenyl ethyl(methyl)carbamate directly reductively coupled with diphenylmethanamine to yield the chiral amine product in 96% ee and 93% yield.
Enantioselective Vanadium-Catalyzed Oxidative Coupling: Development and Mechanistic Insights
Kang, Houng,Herling, Madison R.,Niederer, Kyle A.,Lee, Young Eun,Vasu Govardhana Reddy, Peddiahgari,Dey, Sangeeta,Allen, Scott E.,Sung, Paul,Hewitt, Kirsten,Torruellas, Carilyn,Kim, Gina J.,Kozlowski, Marisa C.
, p. 14362 - 14384 (2018/11/23)
The evolution of a more reactive chiral vanadium catalyst for enantioselective oxidative coupling of phenols is reported, ultimately resulting in a simple monomeric vanadium species combined with a Br?nsted or Lewis acid additive. The resultant vanadium complex is found to effect the asymmetric oxidative ortho-ortho coupling of simple phenols and 2-hydroxycarbazoles with good to excellent levels of enantioselectivity. Experimental and quantum mechanical studies of the mechanism indicate that the additives aggregate the vanadium monomers. In addition, a singlet to triplet crossover is implicated prior to carbon-carbon bond formation. The two lowest energy diastereomeric transition states leading to the enantiomeric products differ substantially with the path to the minor enantiomer involving greater torsional strain between the two phenol moieties.
Tuning ligand structure in chiral bis(phosphite) and mixed phosphite-phosphinite PCP-palladium pincer complexes
Bedford, Robin B.,Chang, Yu-Ning,Haddow, Mairi F.,McMullin, Claire L.
scheme or table, p. 9034 - 9041 (2011/10/30)
A range of chiral resorcinol bis(phosphite) and phosphite-phosphinite ligands were produced and their propensity to form palladium PCP-pincer complexes examined. The ease of base-assisted C-H palladation of the ligands falls in the order bis(phosphinite)
Facile and efficient enantioselective strecker reaction of ketimines by chiral sodium phosphate
Shen, Ke,Liu, Xiaohua,Cai, Yunfei,Lin, Lili,Feng, Xiaoming
supporting information; scheme or table, p. 6008 - 6014 (2010/02/28)
A facile and efficient enantioselective Strecker reaction of ketimines catalyzed by a chiral alkali-metal salt has been developed. When 10 mol% BNPNa (BNP=1,1'-binaphthyl-2,2'-diylphosphate) prepared in situ and 10 mol% para-tert-butylortho-adamantylphenol (PBAP) were introduced into the reaction, up to 96% yield and up to 95% ee (ee=enantiomeric excess) were obtained. Both aliphatic and aromatic ketimines, especially sterically bulky cyclic ketimines derived from β-acetonaphthone, α-indanone, and α-tetralone were found suitable for this reaction. On the basis of the experimental results and previous reports, trimethylsilyl cyanide (TMSCN) was indicated to be the real reactive nucleophile despite the existence of PBAP, and a possible working model was proposed to explain the origin of the asymmetric induction. The facile availability of 1,1'-binaphthyl-2,2'-diylphosphoric acid (BNPH) and the simplicity of the procedure are beneficial for practical applications.
Highly catalytic asymmetric addition of deactivated alkyl Grignard reagents to aldehydes
Da, Chao-Shan,Wang, Jun-Rul,Yin, Xiao-Gang,Fan, Xin-Yuan,Liu, Yi,Yu, Sheng-Li
supporting information; experimental part, p. 5578 - 5581 (2010/03/02)
[Chemical Equation Presented] Generally used and highly reactive RMgBr reagents were effectively deactivated by bis[2-(N,N-dimethylamino)ethyl] ether and then were employed in the highly enantioselective addition of Grignard reagents to aldehydes. The reaction was catalyzed by the complex of commercially available (S)-BINOL and Ti(O'-Pr)4 under mild conditions. Compared with the other observed Grignard reagents, alkyl Grignard reagents showed higher enantioselectivity and they achieved >99% ee.
Copper-catalyzed enantioselective conjugate addition of Grignard reagents to acyclic enones using monodentate phosphoramidite ligands
Maciá, Beatriz,Fernández-Ibá?ez, M. ángeles,Mr?i?, Nata?a,Minnaard, Adriaan J.,Feringa, Ben L.
, p. 1877 - 1880 (2008/09/18)
Herein, we report efficient catalysts based on phosphoramidites for the asymmetric copper-catalyzed conjugate addition of Grignard reagents to acyclic α,β-unsaturated ketones. A variety of Grignard reagents can be added to aliphatic and aromatic acyclic e
A mechanistic investigation of the asymmetric Meerwein-Schmidt-Ponndorf- Verley reduction catalyzed by BINOL/AlMe3 - Structure, kinetics, and enantioselectivity
Graves, Christopher R.,Zhou, Hongying,Stern, Charlotte L.,Nguyen, SonBinh T.
, p. 9121 - 9133 (2008/03/27)
(Chemical Equation Presented) The kinetics of the Al-catalyzed asymmetric Meerwein-Schmidt-Ponndorf-Verley (MSPV) reduction are presented. Structural identification of the catalytic precursor formed in situ between (S)-2,2′-dihydroxy-1,1′-binapthyl ((S)-BINOL), AlMe3, and 2-propanol was established through 1H and 27Al NMR spectroscopies, and APCIMS. All experimental evidence points toward the formation of a BINOL-chelated, pentacoordinate aluminum species in solution. Ligand-accelerated catalysis was confirmed for the phenolate/AlMe 3/2-propanol system. The rate law for the catalytic reaction was determined to be nearly unimolecular dependent on aluminum, zero-order dependent on substrate, and inversely dependent on 2-propanol. At the low catalyst loading employed in the BINOL/AlMe3 system, the inherent reversibility of the MSPV reaction does not affect product yield or enantiomeric excess over time. Systematic ligand studies imply that while a tetrahedral geometry around the aluminum center may result in the most active MSPV reduction catalysts, the enantioselectivity of the reaction is enhanced when the aluminum center allows for a 2-point coordination of the substrate to achieve a pentacoordinate geometry with the fifth ligand weakly coordinated to the axial site of a pseudo square pyramid.
Compositions and methods for selectively binding amines or amino acid enantiomers over their counter-enantiomers
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Page column 15; 16, (2010/11/30)
Naphthyl crown ether ligand molecules containing at least two naphthyl groups that are covalently bonded to suitable solid supports and coated by hydrophobic organic solvents are disclosed. These compositions and associated methods are characterized by selectivity of desired amine or amino acid enantiomers over their counter-enantiomers and derivatives. The composition preferably has an α-value greater than or equal to 4. This allows for the separation of such enantiomers with nonchromatographic resin bed separations of three separation stages or less.
