10017-03-5Relevant academic research and scientific papers
Asymmetric Addition of Hydrogen Cyanide to Substituted Benzaldehydes Catalyzed by a Synthetic Cyclic Peptide, Cyclo((S)-phenylalanyl-(S)-histidyl)
Kobayashi, Yoshiyuki,Asada, Shoichi,Watanabe, Ichigen,Hayashi, Hiroaki,Motoo, Yoshiyuki,Inoue, Shohei
, p. 893 - 896 (1986)
Using cyclo((S)-phenylalanyl-(S)-histidyl) as catalyst, optically active cyanohydrins from substituted benzaldehydes with p-methyl, m-methyl, o-methyl, m-methoxyl, or m-phenoxyl group were obtained with optical yield of 82-33percent.For the asymmetric cyanohydrin synthesis, nonpolar solvent such as benzene or carbon tetrachloride was advantageous, while on asymmetric synthesis took place in methanol or dimethyl sulfoxide.
A novel bifunctional Ti(IV) complex catalyzed asymmetric silylcyanation of aldehydes
Tang, Hongying,Zhang, Zhongbiao
, p. 31 - 35 (2011)
A novel Lewis acid and Lewis base bifunctional Ti(IV) complex was formed in situ upon the treatment of ligand (R)-3,3′-bis(diphenylphosphinoyl)-BINOL with Ti(PrO-i)4, which is proven to be an efficient catalyst in the asymmetric trimethylsilylc
A C2-symmetric chiral bipyridyldiol-titanium complex as a catalyst for the asymmetric trimethylsilylcyanation of substituted benzaldehydes
Lee, Pei-Ting,Chen, Chinpiao
, p. 2704 - 2710 (2005)
This article describes a novel C2-symmetric ligand that comprises a central bipyridine-pinene-derived core and two functionalized two diphenylmethanol subunits. The [8′-(hydroxy-diphenyl-methyl)-10,10, 10′,10′-tetramethyl-[5,5′]bi[6-aza-tricyclo[7.1.1.0 2,7]undecyl]-2(7),3,5,2′(7′),3′, 5′-hexane-8-yl]-diphenyl-methanol 1 is an effective catalyst in the enantioselective addition of trimethylsilylcyanide to various aromatic aldehydes with asymmetric inductions of up to 98% ee. Importantly, the correlation between Hammett substituent constants and the enantiomeric excess, and the electron-releasing group at the meta- and para-positions of substituted benzaldehydes were demonstrated to be associated with the high enantioselectivity of the trimethylsilylcyanation reaction that involves trimethylsilylcyanide.
Stabilization of Hydroxynitrile Lyases from Two Variants of Passion Fruit, Passiflora edulis Sims and Passiflora edulis Forma flavicarpa, by C-Terminal Truncation
Nuylert, Aem,Motojima, Fumihiro,Khanongnuch, Chartchai,Hongpattarakere, Tipparat,Asano, Yasuhisa
, p. 181 - 189 (2020)
Because the synthesis of chiral compounds generally requires a broad range of substrate specificity and stable enzymes, screening for better enzymes and/or improvement of enzyme properties through molecular approaches is necessary for sustainable industri
Discovery and molecular and biocatalytic properties of hydroxynitrile lyase from an invasive millipede, Chamberlinius hualienensis
Dadashipour, Mohammad,Ishida, Yuko,Yamamoto, Kazunori,Asano, Yasuhisa
, p. 10605 - 10610 (2015)
Hydroxynitrile lyase (HNL) catalyzes the degradation of cyanohy-drins and causes the release of hydrogen cyanide (cyanogenesis). HNL can enantioselectively produce cyanohydrins, which are valuable building blocks for the synthesis of fine chemicals and ph
Enantioselective cyanosilylation of aldehydes catalyzed by a novel N,N′-dioxide-Ti(OiPr)4 bifunctional catalyst
Zeng, Baiqing,Zhou, Xin,Liu, Xiaohua,Feng, Xiaoming
, p. 5129 - 5136 (2007)
A novel bifunctional asymmetric catalyst containing N-oxide and titanium(IV) was developed and applied to the asymmetric cyanosilylation of aldehydes. Optically active trimethylsilyl cyanohydrin ethers were obtained up to 99% yield and 80% ee in the presence of 5 mol % catalyst loading at -78 °C. Based on the experimental results, the catalytic cycle was proposed as a pathway in which Lewis acid and Lewis base activated aldehyde and trimethylsilylcyanide (TMSCN), respectively.
Enantioselective hydrocyanation of aldehydes catalyzed by [Li{Ru(phgly)2(binap)}]X (X = Cl, Br)
Kurono, Nobuhito,Yoshikawa, Tatsuya,Yamasaki, Mikio,Ohkuma, Takeshi
, p. 1254 - 1257 (2011)
Novel bimetallic complexes [Li{Ru[(S)-phgly]2[(S)-binap]}]X (X = Cl, Br) are readily synthesized by mixing Ru[(S)-phgly]2[(S)-binap] and LiX. A single-crystal X-ray analysis reveals the structure. These bimetallic complexes efficient
A simple separation method for (S)-hydroxynitrile lyase from cassava and its application in asymmetric cyanohydrination
Zheng, Zubiao,Zi, Yan,Li, Zhongzhou,Zou, Xinzhuo
, p. 434 - 439 (2013)
Using an acetone precipitation method, crude (S)-hydroxynitrile lyase [(S)-MeHNL] was separated from Munihot esculenta (cassava) leaves, and used directly as biocatalyst to catalyze asymmetric cyanohydrination and produce cyanohydrins with enantiomeric purities (≥90% ee) significantly greater than those previously reported. The use of a water/i-Pr2O system with an enzyme, NaCN, and appropriate amounts of acetic acid is crucial in improving the stereoselectivity of cyanohydrin formation by minimizing the non-enzymatic reaction and the racemization of the chiral products. The proposed isolation method for crude (S)-MeHNL has a high value because of its simplicity, and low cost as well as the high activity of the crude (S)-MeHNL.
Enantioselective cyanosilylation of aldehydes catalyzed by a multistereogenic salen-Mn(III) complex with a rotatable benzylic group as a helping hand
Wei, Yun-Long,Huang, Wei-Sheng,Cui, Yu-Ming,Yang, Ke-Fang,Xu, Zheng,Xu, Li-Wen
, p. 3098 - 3103 (2015/02/02)
A multistereogenic salen-Mn(iii) complex bearing an aromatic pocket and two benzylic groups as helping hands was found to be efficient in the catalysis of asymmetric cyanosilylation. The salen-Mn catalyst partially mimics the functions of biocatalysts by
Solid phase behavior in the chiral systems of various 2-hydroxy-2-phenylacetic acid (mandelic acid) derivatives
Von Langermann, Jan,Temmel, Erik,Seidel-Morgenstern, Andreas,Lorenz, Heike
, p. 721 - 728 (2015/03/30)
The solid phase behavior of a series of monosubstituted F-, Cl-, Br-, I-, and CH3- and two 2,4-halogen-disubstituted 2-hydroxy-2-phenylacetic acid (mandelic acid) derivatives was investigated. The study includes detailed information about melting temperature, melting enthalpy, X-ray diffraction data, as well as selected binary phase diagrams of the respective chiral systems. Aside from the known metastable conglomerate 2-chloromandelic acid, evidence for two more metastable conglomerates was found.
