10017-04-6Relevant articles and documents
Titanium and ruthenium binaphthyl Schiff base complexes as catalysts for asymmetric trimethylsilylcyanation of aldehydes
Zhou, Xiang-Ge,Huang, Jie-Sheng,Ko, Po-Hung,Cheung, Kung-Kai,Che, Chi-Ming
, p. 3303 - 3309 (1999)
Investigations on the catalytic behaviour of titanium complexes formed in situ from Ti(OPri)4 and a variety of Schiff bases, mainly the binaphthyl derivatives 2,2′-bis(3-R1-5-R 2-2-hydroxybenzylideneamino)-1,1′-binaphthyl, toward the asymmetric trimethylsilylcyanation of some aromatic and aliphatic aldehydes demonstrated that the titanium complex of the binaphthyl Schiff base with R1 = R2 = But is one of the best catalysts for such a process, with an enantiomeric excess (e.e.) as high as 96% obtained for m-tolualdehyde. Crystal structure determination of a nitrosylruthenium complex, [RuII(L)(NO)Cl] (L is the dianion of the binaphthyl Schiff base with R1 = R2 = Cl), revealed that the complex assumes a cis-β configuration with the binaphthyl moiety having a dihedral angle of 70.2°. After treatment with AgPF6, the ruthenium complex also exhibited a good catalytic property for the trimethylsilylcyanation of benzaldehyde albeit with a lower e.e. (24%). The Royal Society of Chemistry 1999.
A new bifunctional asymmetric catalysis: An efficient catalytic asymmetric cyanosilylation of aldehydes [23]
Hamashima, Yoshitaka,Sawada, Daisuke,Kanai, Motomu,Shibasaki, Masakatsu
, p. 2641 - 2642 (1999)
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(R)- and (S)-cyanohydrins using oxynitrilases in whole cells
Kiljunen, Eero,Kanerva, Liisa T.
, p. 1105 - 1116 (1996)
Almond meal and Sorghum bicolor shoots were used as the sources of oxynitrilases for the preparation of a number (R)- and (S)-arylcyanohydrins, respectively, from the corresponding aldehydes in diisopropyl ether. Two different in situ methods were used to introduce hydrogen cyanide into the reaction mixture. In method 1, acetone cyanohydrin decomposes enzymatically and/or chemically to hydrogen cyanide. In method 2, hydrogen cyanide freely evaporates from a solution in diisopropyl ether from one compartment of the reaction vessel and ends up to the other where it dissolves into the reaction mixture.
Asymmetric cyanohydrin formation from aldehydes catalyzed by manganese Schiff base complexes
Qu, Yanyang,Jing, Linhai,Wu, Zhiqing,Wu, Di,Zhou, Xiangge
, p. 187 - 190 (2010)
The catalyst generated in situ from Mn(OAc)2 and a chiral Schiff base ligand exhibited excellent catalytic abilities in asymmetric cyanohydrin formation from aldehydes with sodium cyanide in up to 99% enantioselectivity and good yield.
Synthesis of new chiral Schiff bases and their application in the asymmetric trimethylsilylcyanation of aromatic aldehydes
Yang, Zhuo-Hong,Wang, Li-Xin,Zhou, Zheng-Hong,Zhou, Qi-Lin,Tang, Chu-Chi
, p. 1579 - 1582 (2001)
The new chiral Schiff base ligands 1a-1c were synthesized from (1R)-(+)-camphor and found to be efficient catalysts for the enantioselective silylcyanation of aromatic aldehydes. The corresponding aromatic cyanohydrins were obtained in good yields and with enantiomeric excesses (e.e.s) of up to 73%.
Chemoenzymatic flow cascade for the synthesis of protected mandelonitrile derivatives
Delville, Marille M. E.,Koch, Kaspar,Van Hest, Jan C. M.,Rutjes, Floris P. J. T.
, p. 1634 - 1638 (2015)
A chemoenzymatic two-step cascade process, with both steps having incompatible reaction conditions, was successfully performed in continuous flow. The chemoenzymatic aqueous formation of cyanohydrins was integrated with a subsequent organic phase protection step in a single flow process utilising a membrane-based phase separation module. The wider applicability of our setup was demonstrated with the synthesis of nine protected cyanohydrin derivatives, all obtained in good yields and high to excellent enantioselectivity.
Enantioselective trimethylsilylcyanation of aldehydes catalyzed by chiral lanthanoid alkoxides
Qian, Changtao,Zhu, Chengjian,Huang, Taisheng
, p. 2131 - 2132 (1998)
The first example of enantioselective trimethylsilylcyanation of aldehydes catalyzed by chiral binaphthol and binaphthol-modified lanthanum alkoxides has been achieved, in which an obvious effect of substituents at the 3,3′-positions of BINOL on the enantioselectivity was observed and 3,3′-bis(methoxyethyl)-BINOL had the advantage over simple BINOL to give (S)-products in excellent yields with 73% ee.
Multivariate Metal-Organic Frameworks as Multifunctional Heterogeneous Asymmetric Catalysts for Sequential Reactions
Xia, Qingchun,Li, Zijian,Tan, Chunxia,Liu, Yan,Gong, Wei,Cui, Yong
supporting information, p. 8259 - 8266 (2017/06/28)
The search for versatile heterogeneous catalysts with multiple active sites for broad asymmetric transformations has long been of great interest, but it remains a formidable synthetic challenge. Here we demonstrate that multivariate metal-organic frameworks (MTV-MOFs) can be used as an excellent platform to engineer heterogeneous catalysts featuring multiple and cooperative active sites. An isostructural series of 2-fold interpenetrated MTV-MOFs that contain up to three different chiral metallosalen catalysts was constructed and used as efficient and recyclable heterogeneous catalysts for a variety of asymmetric sequential alkene epoxidation/epoxide ring-opening reactions. Interpenetration of the frameworks brings metallosalen units adjacent to each other, allowing cooperative activation, which results in improved efficiency and enantioselectivity over the sum of the individual parts. The fact that manipulation of molecular catalysts in MTV-MOFs can control the activities and selectivities would facilitate the design of novel multifunctional materials for enantioselective processes.
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
