2385-77-5Relevant articles and documents
Synthesis of Citronellal by RhI-Catalysed Asymmetric Isomerization of N,N-Diethyl-Substituted Geranyl- and Nerylamines or Geraniol and Nerol in the Presence of Chiral Diphosphino Ligands, under Homogeneous and Supported Conditions
Chapuis, Christian,Barthe, Michel,Laumer, Jean-Yves de Saint
, p. 230 - 242 (2001)
For the asymmetric isomerization of geranyl- or neryldiethylamine (( E)- or(Z)-1, resp.) and allyl alcohols geraniol or nerol ((E)- or (Z)-2, resp.) to citronellal (4) in the presence of a [RhI(ligand)cycloocta-1,5-diene)]- catalyst, the atropic ligands 5-11 are compared under homogeneous and polymer-supported conditions with the non-C2-symmetrical diphosphino ferrocene ligands 12-16. The tBu-josiphos ligand 13 or daniphos ligand 19, available in both antipodal series, already catalyse the reaction of (E)-1 at 20 deg (97 percent e.e.) and favourably compare with the binap ligand 5 (see Table 1). Silica-gel- or polymer-supported diphosphino ligands usually afford similar selectivity as compared to the corresponding ligands applied under homogeneous conditions, but are generally less reactive. In this context, a polymer-supported ligand of interest is the polymer-anchored binap (R)-6, in terms of reactivity, selectivity, and recoverability, with a turnover of more than 14400.
Chiral 3D open-framework material Ni(D-cam)(H2O)2 used as GC stationary phase
Xie, Shengming,Wang, Bangjin,Zhang, Xinhuan,Zhang, Junhui,Zhang, Mei,Yuan, Liming
, p. 27 - 32 (2014)
Metal-organic frameworks (MOFs) have been explored for analytical applications because of their outstanding properties such as high surface areas, flexibility and specific structure features, especially for chromatography application in recent years. In this work, a chiral MOF Ni(D-cam)(H 2O)2 with unusual integration of molecular chirality, absolute helicity, and 3-D intrinsic chiral net was chosen as stationary phase to prepare Ni(D-cam)(H2O)2-coated open tubular columns for high-resolution gas chromatographic (GC) separation. Two fused-silica open tubular columns with different inner diameters and lengths, including column A (30 m × 250 μm i.d.) and column B (2 m × 75 μm i.d.), were prepared via a dynamic coating method. The chromatographic properties of the two columns were investigated using n-dodecane as the analyte at 120 °C. The number of theoretical plates (plates/m) of the two metal-organic framework (MOF) columns was 1300 and 2750, respectively. The racemates, isomer and linear alkanes mixture were used as analytes for evaluating the separation properties of Ni(D-cam)(H2O)2-coated open tubular columns. The results showed that the columns offered good separations of isomer and linear alkanes mixture, especially racemates. Chirality 26:27-32, 2013. 2013 Wiley Periodicals, Inc.
Asymmetric cleavage of chiral α,β-ethylenic acetals by organolithium reagents
Alexakis, Alexandre,Mhamdi, Farida,Lagasse, Franz,Mangeney, Pierre
, p. 3343 - 3346 (1996)
,β-Ethylenic chiral acetals react regio- and stereoselectively with organolithium reagents. The obtained enol ether may be hydrolyzed into a chiral β-disubstituted aldehyde.
Investigating the Structure-Reactivity Relationships Between Nicotinamide Coenzyme Biomimetics and Pentaerythritol Tetranitrate Reductase
Tan, Zhuotao,Han, Yaoying,Fu, Yaping,Zhang, Xiaowang,Xu, Mengjiao,Na, Qi,Zhuang, Wei,Qu, Xudong,Ying, Hanjie,Zhu, Chenjie
, p. 103 - 113 (2021/10/07)
Ene reductases (ERs) are attractive biocatalysts in terms of their high enantioselectivity and expanded substrate scope. Recent works have proved that synthetic nicotinamide coenzyme biomimetics (NCBs) can be used as easily accessible alternatives to natural cofactors in ER-catalyzed reactions. However, the structure-reactivity relationships between NCBs and ERs and influence factors are still poorly understood. In this study, a series of C-5 methyl modified NCBs were synthesized and tested in the PETNR-catalyzed asymmetric reductions. The physicochemical properties of these NCBs including electrochemical properties, stability, and kinetic behavior were studied in detail. The results showed that hydrophobic interaction caused by the introduced methyl group contributed to the stabilization of binding conformation in enzyme active site, resulting in comparable catalytic activity with that of NADPH. Molecular dynamics and steered molecular dynamics simulations were further performed to explain the binding mechanism between PETNR and NCBs, which revealed that stable catalytic conformation, appropriate donor-acceptor distance and angle, as well as free dissociation energy are important factors affecting the activity of NCBs. (Figure presented.).
Multicatalytic approach to one-pot stereoselective synthesis of secondary benzylic alcohols
Casnati, Alessandra,Lichosyt, Dawid,Lainer, Bruno,Veth, Lukas,Dydio, Pawe?
supporting information, p. 3502 - 3506 (2021/05/10)
One-pot procedures bear the potential to rapidly build up molecular complexity without isolation and purification of consecutive intermediates. Here, we report multicatalytic protocols that convert alkenes, unsaturated aliphatic alcohols, and aryl boronic acids into secondary benzylic alcohols with high stereoselectivities (typically >95:5 er) under sequential catalysis that integrates alkene cross-metathesis, isomerization, and nucleophilic addition. Prochiral allylic alcohols can be converted to any stereoisomer of the product with high stereoselectivity (>98:2 er, >20:1 dr).
Chemoselective γ-Oxidation of β,γ-Unsaturated Amides with TEMPO
Heindl, Sebastian,Lemmerer, Miran,Malzer, Nicolas,Matyasovsky, Ján,Maulide, Nuno,Riomet, Margaux
supporting information, p. 19123 - 19127 (2021/07/26)
A chemoselective and robust protocol for the γ-oxidation of β,γ-unsaturated amides is reported. In this method, electrophilic amide activation, in a rare application to unsaturated amides, enables a regioselective reaction with TEMPO resulting in the title products. Radical cyclisation reactions and oxidation of the synthesised products highlight the synthetic utility of the products obtained.
Method for preparing optically active citronellal and catalyst system for method
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Paragraph 0071-0085, (2020/05/05)
The invention provides a method for preparing optically active citronellal and a catalyst system for the method. The method comprises the step that in the presence of a catalyst, neryl aldehyde shownin the formula (I) and/or geranial shown in the formula (II) are/is subjected to asymmetric hydrogenation to prepare optically active R-citronellal shown in the formula (III), and the catalyst comprises rhodium serving as a catalytic activity transition metal, a chiral bidentate diphosphine ligand and TiO2-loaded activated carbon. According to the method, the stereoselectivity of the reaction canbe remarkably improved, and the R-citronellal with high optical purity is obtained.
Method for preparing R-citronellal
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, (2020/10/12)
The invention provides a method for preparing R-citronellal. The method comprises the following steps: (1) synthesizing a chiral unsaturated compound containing cis-trans isomers from citral and azacyclo-phenyl chiral blocks; (2) crystallizing and separating the chiral unsaturated compound at a low temperature to obtain a cis-isomer and a trans-isomer; (3) performing asymmetric hydrogenation on the cis-isomer under the action of an R, R-type chiral metal catalyst to prepare an R-type chiral saturated compound; and/or carrying out asymmetric hydrogenation on the trans-isomer under the action ofan S, S-type chiral metal catalyst to prepare the R-type chiral saturated compound; and (4) carrying out hydrolysis reaction on the R-type chiral saturated compound to obtain R-citronellal. The citral used in the method does not need to be subjected to pretreatment separation, the total yield of a synthesis route is high, the product selectivity is extremely high due to the synergistic effect ofthe azacyclo-phenyl chiral blocks and the chiral metal catalyst, the atom utilization rate in the condensation and hydrolysis reaction process is high, and the method is suitable for industrial production of chiral citronellal.
Preparation method of optically active citronellal (by machine translation)
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Paragraph 0081-0085; 0093-0097, (2020/03/17)
The preparation method of the optically active citronellal can significantly improve the catalytic stability, of the optically active transition metal catalyst for homogeneous catalysis to obtain, the optically active citronellal. which is obtained by reacting a transition metal compound with an optically active ligand containing two phosphorus atoms, and, or iron in the substrate material used for the asymmetric hydrogenation reaction . is prepared by reacting a transition metal compound with an optically active ligand containing two phosphorus atoms in the presence of a transition metal catalyst in the preparation method of the optically active citronellal with an asymmetric hydrogenation reaction in the presence of a transition metal catalyst to achieve a higher degree of peripheral speed, ≤6mgKOH/g/of the optically ≤50ppm. active citronellal. (by machine translation)
Method for preparing optically active citronellal (by machine translation)
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Paragraph 0085-0089; 0097-0100, (2020/05/05)
The invention provides a method, for preparing optically active citronellal by reacting a transition metal catalyst with an asymmetric hydrogenation reaction, to obtain the optically active citronellal, wherein the substrate is neral and/or the vanillic, catalyst is obtained, by controlling the catalytic activity ≤500ppm of the asymmetric hydrogenation reaction substrate and remarkably improving the service life of the catalyst by controlling the asymmetric hydrogenation reaction substrate through oxidation . and ≤10ppm, or the aqueous chlorine, catalyst obtained by reacting the transition metal compound with the optically, active ligand containing .the two phosphorus atoms to obtain the optically active citronellal. (by machine translation)
