Enantioselective cyanosilylation of aldehydes catalyzed by novel camphor derived Schiff bases-titanium(IV) complexes
作者:Ewelina Błocka、Mariusz J. Bosiak、Mirosław Wełniak、Agnieszka Ludwiczak、Andrzej Wojtczak
DOI:10.1016/j.tetasy.2014.03.001
日期:2014.4
Five tridentate Schiff bases have been prepared from (1R,2S,3R,4S)-3-amino-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol and salicylaldehydes. X-ray structure investigation revealed differences in their molecular conformation, and their titanium(IV) complexes have been studied with NMR techniques. Among them the complex with the Schiffbase obtained from 2-hydroxy-3-isopropylbenzaldehyde, is the most selective
Chiral Metal–Organic Framework Decorated with TEMPO Radicals for Sequential Oxidation/Asymmetric Cyanation Catalysis
作者:Zijian Li、Yan Liu、Xing Kang、Yong Cui
DOI:10.1021/acs.inorgchem.8b01630
日期:2018.8.20
cocrystallizing achiral (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-substituted tricarboxylate and enantiopure VO(salen)-derived dipyridine ligands. The chiral MOF can function as an efficient heterogeneous catalyst for the sequential alcoholoxidation/asymmetric cyanation of aldehyde reactions with enhanced activity and enantioselectivity compared to the homogeneous counterpart.
The Asymmetric Addition of Trimethylsilyl Cyanide to Aldehydes Catalyzed by Chiral (Salen)Titanium Complexes
作者:Yuri N. Belokon'、Susana Caveda-Cepas、Brendan Green、Nicolai S. Ikonnikov、Viktor N. Khrustalev、Vladimir S. Larichev、Margarita A. Moscalenko、Michael North、Charles Orizu、Vitali I. Tararov、Michela Tasinazzo、Galina I. Timofeeva、Lidia V. Yashkina
DOI:10.1021/ja984197v
日期:1999.4.1
The use of chiral (salen)TiCl2 complexes to induce the asymmetricaddition of trimethylsilyl cyanide to aldehydes has been investigated. The complexes are catalytically active at substrate-to-catalyst ratios as high as 1000:1, and the optimal catalyst (2e) which is derived from (R,R)-1,2-diaminocyclohexane and 3,5-di-tert-butyl-2-hydroxybenzaldehyde produces trimethylsilyl ethers of cyanohydrins with
Fine Modification of Salen Ligands - Effects on the Salen-Ti-Catalyzed Asymmetric Cyanosilylation of Aldehydes
作者:Chengwei Lv、Qigan Cheng、Daqian Xu、Shoufeng Wang、Chungu Xia、Wei Sun
DOI:10.1002/ejoc.201100319
日期:2011.7
bifunctional N-oxide salen―Ti IV complexes and a pyrrolidine salen―Ti IV complex in combination with achiral N-oxide were developed and applied to the asymmetricaddition of trimethylsilyl cyanide to aldehydes. Notably, both enantiomers of trimethylsilyl ethers of cyanohydrins could be easily prepared by modifying the catalysts employed in this reaction, which are based on the same chiral diamine collar
开发了新的双功能 N-氧化物 salen-Ti IV 配合物和吡咯烷 salen-Ti IV 配合物与非手性 N-氧化物的结合,并将其应用于三甲基氰基氰化物与醛的不对称加成。值得注意的是,氰醇的三甲基甲硅烷基醚的两种对映异构体都可以通过修改该反应中使用的催化剂来轻松制备,这些催化剂基于相同的手性二胺环,源自 L-酒石酸。通过使用相对低的催化剂负载量和仅 1.05 当量的三甲基氰基氰化物 (TMSCN),通常以中等至良好的对映体过量和优异的产率获得产物。
Asymmetric addition of trimethylsilyl cyanide to aldehydes promoted by chiral polymeric vanadium(V) salen complex as an efficient and recyclable catalyst
作者:Noor-ul H. Khan、Santosh Agrawal、Rukhsana I. Kureshy、Sayed H.R. Abdi、Vishal J. Mayani、Raksh V. Jasra
DOI:10.1016/j.tetasy.2006.09.024
日期:2006.10
The asymmetric addition of trimethylsilyl cyanide to various aldehydes catalyzed by efficient new vanadyl polymeric salen complexes having 12 repeating salen units was investigated at room temperature. An excellent yield of the trimethylsilylether of cyanohydrins (up to 98%) with high chiral induction (96%) in case of 2-methylbenzaldehyde was achieved in 18 h. The catalyst recovered four times with