168013-75-0Relevant articles and documents
Constructing a triangular metallacycle with salen-Al and its application to a catalytic cyanosilylation reaction
Li, Bo,Li, Yang,Qiu, Huayu,Xu, Jun,Yin, Shouchun,Zhang, Jinjin,Zhang, Pengfei,Zhang, Yueyue
, p. 10399 - 10402 (2021/10/12)
A triangular metallosalen-based metallacycle was constructed in quantitative yield by the self-assembly of a 180° bis(pyridyl)salen-Al complex and a 60° diplatinum(ii) acceptor in a 1?:?1 stoichiometric ratio. This metallacycle was then successfully used to cyanosilylate a wide range of benzaldehydes with trimethylsilyl cyanide.
Acceptorless and Base-free Dehydrogenation of Cyanohydrin with (η6-Arene)halide(Bidentate Phosphine)ruthenium(II) Complex
Kim, Kicheol,Moeljadi, Adhitya Mangala Putra,Hirao, Hajime,Hong, Soon Hyeok
supporting information, p. 3292 - 3298 (2017/09/06)
Ruthenium-catalyzed dehydrogenation of cyanohydrins under acceptorless and base-free conditions was demonstrated for the first time in the synthesis of acyl cyanide. As opposed to the thermodynamically preferred elimination of hydrogen cyanide, the dehydrogenation of cyanohydrins could be kinetically controlled with ruthenium (II) bidentate phosphine complexes. The effects of the arene, phosphine ligands and counter anions were investigated in regard to catalytic activity and selectivity. Selective dehydrogenation can occur via β-hydride elimination with the experimentally observed [(alkoxide)Ru] complex. (Figure presented.).
An orthogonal biocatalytic approach for the safe generation and use of HCN in a multistep continuous preparation of chiral O-acetylcyanohydrins
Brahma, Aischarya,Musio, Biagia,Ismayilova, Uliviya,Nikbin, Nikzad,Kamptmann, Sonja B.,Siegert, Petra,Jeromin, Günter E.,Ley, Steven V.,Pohl, Martina
supporting information, p. 262 - 266 (2016/01/20)
An enantioselective preparation of O-acetylcyanohydrins has been accomplished by a three-step telescoped continuous process. The modular components enabled an accurate control of two sequential biotransformations, safe handling of an in situ generated hazardous gas, and in-line stabilization of products. This method proved to be advantageous over the batch protocols in terms of reaction time (40 min vs 345 min) and ease of operation, opening up access to reactions which have often been neglected due to safety concerns.
Cooperative thiourea-Bronsted acid organocatalysis: Enantioselective cyanosilylation of aldehydes with TMSCN
Zhang, Zhiguo,Lippert, Katharina M.,Hausmann, Heike,Kotke, Mike,Schreiner, Peter R.
, p. 9764 - 9776 (2012/01/03)
We report a new thiourea - Bronsted acid cooperative catalytic system for the enantioselective cyanosilylation of aldehydes with yields up to 90% and enantioselectivities up to 88%. The addition of an achiral acid was found to be crucial for high asymmetric induction. Mechanistic investigations using a combination of NMR, ESI-MS, and density functional theory computations (including solvent corrections) at the M06/6-31G(d,p) level of theory suggest that the key catalytic species results from the cooperative interaction of bifunctional thioureas and an achiral acid that form well-defined chiral hydrogen-bonding environments.
Dibutyltin dimethoxide-catalyzed cyano transfer to aldehydes and imines
Yanagisawa, Akira,Matsumoto, Takuya,Kushihara, Naoyuki,Yoshida, Kazuhiro
experimental part, p. 2918 - 2922 (2011/01/05)
A novel reaction involving cyano transfer from benzophenone cyanohydrin to aldehydes and imines was realized by using dibutyltin dimethoxide as a catalyst. Various cyanohydrins and α-amino nitriles were obtained in moderate to high yields by this reaction. Ketimines also showed remarkable reactivity as cyano acceptors under conventional reaction conditions. This catalytic reaction was further applied to a three-component condensation reaction of aldehydes, aniline, and benzophenone cyanohydrin in the presence of Drierite. Copyright
Enzymatic kinetic resolution of racemic cyanohydrins via enantioselective acylation
Xu, Qing,Xie, Yongli,Geng, Xiaohong,Chen, Peiran
supporting information; experimental part, p. 624 - 630 (2010/09/07)
Enzymatic kinetic resolution of a series of aromatic and aliphatic cyanohydrins in organic media has been investigated. The behavior of potential lipases, molecular sieves, acyl reagent, reaction temperature, and organic solvents on the kinetic resolution was studied. The influence of substrate structure, steric, and electronic nature and position of the aryl substituent on the enantioselectivity was discussed. Under the optimized reaction conditions, good enantioselectivity could be achieved for most of the investigated compounds. Specifically, substrates 1a, 1c, 1d, 1f, 1u could be resolved with the kinetic enantiomer ratio (E) higher than 200.
Lipase-catalyzed dynamic kinetic resolution giving optically active cyanohydrins: use of silica-supported ammonium hydroxide and porous ceramic-immobilized lipase
Sakai, Takashi,Wang, Kefei,Ema, Tadashi
, p. 2178 - 2183 (2008/09/18)
Synthetically useful cyanohydrin acetates, ArCH(OAc)CN (Ar=C6H5, 3,4-methylenedioxyphenyl, 4-Me-C6H4, 4-Cl-C6H4, 4-F-C6H4, 4-CF3-C6H4), were successfully synthesized in high enantiomeric purities (79-93% ee) via the lipase-catalyzed dynamic kinetic resolution (DKR) of cyanohydrins synthesized in situ from the corresponding aldehydes and acetone cyanohydrin. The combined use of silica-supported BTAH (benzyltrimethylammonium hydroxide) and porous ceramic-immobilized lipase under the optimized reaction conditions enabled the remarkable acceleration of the enantioselective DKR reactions.
A new (R)-hydroxynitrile lyase from Prunus mume: Asymmetric synthesis of cyanohydrins
Nanda, Samik,Kato, Yasuo,Asano, Yasuhisa
, p. 10908 - 10916 (2007/10/03)
A new hydroxynitrile lyase (HNL) was isolated from the seed of Japanese apricot (Prunus mume). The enzyme has similar properties with HNL isolated from other Prunus species and is FAD containing enzyme. It accepts a large number of unnatural substrates (benzaldehyde and its variant) for the addition of HCN to produce the corresponding cyanohydrins in excellent optical and chemical yields. A new HPLC based enantioselective assay technique was developed for the enzyme, which promotes the addition of KCN to benzaldehyde in a buffered solution (pH=4.5).
Vanadium-catalyzed asymmetric oxidation of α-hydroxy esters using molecular oxygen as stoichiometric oxidant
Radosevich, Alexander T.,Musich, Christine,Toste, F. Dean
, p. 1090 - 1091 (2007/10/03)
A vanadium-catalyzed method for the oxidative kinetic resolution of α-hydroxyesters, using oxygen as the terminal oxidant, is described. The catalyst is generated in situ from vanadium(V) tri-iso-propoxyoxide in combination with a tridentate ligand derived from 3,5-di-tert-butylsalicylaldehyde and (S)-tert-leucinol. The reaction allows for the enantioselective synthesis of both aromatic and aliphatic secondary alcohols, including those containing olefins and alkynes. Copyright
(R)-Oxynitrilase-catalyzed hydrocyanation: The first synthesis of optically active fluorinated mandelonitriles
Han, Shiqing,Chen, Peiran,Lin, Guoqiang,Huang, Hao,Li, Zuyi
, p. 843 - 846 (2007/10/03)
The first enantioselective synthesis of (R)-fluorinated mandelonitriles, by hydrocyanation under micro-aqueous conditions with almond meal as catalyst is reported.
