177186-35-5Relevant academic research and scientific papers
Enantioselective cyanosilylation of aldehydes catalyzed by novel camphor derived Schiff bases-titanium(IV) complexes
B?ocka, Ewelina,Bosiak, Mariusz J.,We?niak, Miros?aw,Ludwiczak, Agnieszka,Wojtczak, Andrzej
, p. 554 - 562 (2014/05/06)
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
Fine modification of salen ligands - Effects on the salen-Ti-catalyzed asymmetric cyanosilylation of aldehydes
Lv, Chengwei,Cheng, Qigan,Xu, Daqian,Wang, Shoufeng,Xia, Chungu,Sun, Wei
supporting information; experimental part, p. 3407 - 3411 (2011/09/12)
New bifunctional N-oxide salen-TiIV complexes and a pyrrolidine salen-TiIV complex in combination with achiral N-oxide were developed and applied to the asymmetric addition of trimethylsilyl cyanide to aldehydes. Notably, both enanti
CYANATION CATALYST AND METHOD FOR PRODUCING OPTICALLY ACTIVE CYANHYDRIN COMPOUND USING THE SAME
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Page/Page column 9-10, (2010/03/02)
The present invention can provide a cyanation catalyst represented by the general formula (I): (in the formula (I), R1 through R4 are each an optionally substituted hydrocarbon group; R1 and R2 and/or R3 and R4 may form an optionally substituted carbon chain ring; R5 through R8 are each a hydrogen atom, or an optionally substituted hydrocarbon group; R5 and R6 and/or R7 and R8 may form an optionally substituted carbon chain ring; R9 and R10 are each a hydrogen atom, or an optionally substituted hydrocarbon group; W, X and Y each represent an optionally substituted binding chain; X and/or Y may be non-existent; M represents a metal or a metal ion; and ligands of M may each be located at any position).
An efficient titanium catalyst for enantioselective cyanation of aldehydes: Cooperative catalysis
Zhang, Zhipeng,Wang, Zheng,Zhang, Ruzhou,Ding, Kuiling
supporting information; experimental part, p. 6746 - 6750 (2010/12/24)
(Figure Presented) Two-in-one: The integration of two salen/ Ti=O units into one molecule allows the enantioselective cyanation of aldehydes to afford the enantioenriched natural or nonnatural cyanohydrin derivatives with turnover numbers of 1960-172000 a
Synthesis of the bifunctional BINOL ligands and their applications in the asymmetric additions to carbonyl compounds
Qin, Ying-Chuan,Liu, Lan,Sabat, Michal,Pu, Lin
, p. 9335 - 9348 (2007/10/03)
Efficient one-step syntheses of the bifunctional BINOL and H8BINOL ligands (S)-6 and (S)-8 have been developed from the reaction of BINOL and H8BINOL with morpholinomethanol, respectively. The X-ray analyses of these compounds have revealed their structural similarity and difference. The bifunctional H8BINOL (S)-8 is found to be highly enantioselective for the reaction of diphenylzinc with many aliphatic and aromatic aldehydes and especially is the most enantioselective catalyst for linear aliphatic aldehydes. Unlike other catalysts developed for the diphenylzinc addition which often require the addition of a significant amount of diethylzinc with cooling (or heating) the reaction mixture in order to achieve high enantioselectivity, using (S)-8 needs no additive and gives excellent results at room temperature. (S)-8 in combination with diethylzinc and Ti(OiPr)4 can catalyze the highly enantioselective phenylacetylene addition to aromatic aldehydes. It can also promote the phenylacetylene addition to acetophenone at room temperature though the enantioselectivity is not very high yet. Without using Ti(OiPr)4 and a Lewis base additive, (S)-8 in combination with diethylzinc can catalyze the reaction of methyl propiolate with an aldehyde to form the highly functional γ-hydroxy-α,β-acetylenic esters except that the enantioselectivity is low at this stage. The bifunctional BINOL ligand (S)-6 in combination with Me2AlCl is found to be a highly enantioselective catalyst for the addition of TMSCN to both aromatic and aliphatic aldehydes.
Asymmetric cyanosilylation of aldehydes catalyzed by novel chiral tetraaza-titanium complexes
Liu, Yanling,Liu, Xiaohua,Xin, Junguo,Feng, Xiaoming
, p. 1085 - 1089 (2007/10/03)
The asymmetric addition of trimethylsilyl cyanide (TMSCN) to a range of aldehydes was efficiently catalyzed by a novel, easily prepared C 2-symmetric chiral tetraaza-Ti(IV) complex in high yields with up to 92% ee under mild conditions. A negative nonlinear effect between the ee of the ligand and the ee of the product was observed. Georg Thieme Verlag Stuttgart.
Thiourea-catalyzed enantioselective cyanosilylation of ketones
Fuerst, Douglas E.,Jacobsen, Eric N.
, p. 8964 - 8965 (2007/10/03)
The new chiral amino thiourea catalyst 3d promotes the highly enantioselective cyanosilylation of a wide variety of ketones. The hindered tertiary amine substituent plays a crucial role with regard to both stereoinduction and reactivity, suggesting a coop
Asymmetric cyanohydrin synthesis catalyzed by Al(salen)/triphenylphosphane oxide
Kim, Sung Soo,Song, Dae Ho
, p. 1777 - 1780 (2007/10/03)
Various aldehydes undergo asymmetric trimethylsilylcyanation with (CH 3)3SiCN (TMSCN) in the presence of a chiral Al(salen) complex and Ph3PO as the catalyst. This is a double activation where Al(salen) plays the role of Lewis acd and POPh3 acts as a Lewis base. Various kind of aldehydes were subjected to the enantioselective addition of (CH3)3SiCN at temperatures between -40 °C and -50 °C. Hydrolysis of the adducts gave cyanohydrins with over 90 % yield and 80 % ee in most cases. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
Development of β-hydroxyamide/titanium complexes for catalytic enantioselective silylcyanation of aldehydes
Uang, Biing-Jiun,Fu, I-Pin,Hwang, Chyuan-Der,Chang, Chun-Wei,Yang, Chun-Tzu,Hwang, Der-Ren
, p. 10479 - 10486 (2007/10/03)
A highly enantioselective addition of trimethylsilylcyanide to aldehydes catalyzed by chiral titanium complexes is described. The chiral titanium complexes were prepared in situ from Ti(OiPr)4 and β-hydroxyamide ligands, that could easily be synthesized from ketopinic acid and C2 symmetrical chiral diamines in a small number of steps. Graphical Abstract.
Enantioselective addition of trimethylsilyl cyanide to aldehydes catalysed by bifunctional BINOLAM-AlCl versus monofunctional BINOL-AlCl complexes
Casas, Jesús,Nájera, Carmen,Sansano, José M.,Saá, José M.
, p. 10487 - 10496 (2007/10/03)
A highly enantioselective cyanation of aldehydes takes place by using a bifunctional catalyst derived from 3,3′-bis(diethylaminomethyl) substituted binaphthol (BINOLAM) and dimethylaluminium chloride. The addition is of wide scope and runs best in toluene at temperatures ranging from -20 to -40°C, in the presence of 4 A? MS and triphenylphosphine oxide as additives. The (R)- or (S)-cyanohydrins result when using (S)- or (R)-BINOLAM-AlCl complexes, respectively. The valuable ligand can be recovered by simple extractive work-up and recycled without loss of efficiency (both in terms of chemical and stereochemical yields). This methodology is applied to the Shibasaki synthesis of epothilone A. All the evidence available for the BINOLAM-AlCl enantioselective addition of TMSCN to aldehydes call for the intervention of a hydrocyanation reaction, addition of a catalytic amount of hydrogen cyanide, generated in situ, to an aldehyde, followed by O-silylation. In order to determine the role of the basic amino groups of BINOLAM, comparative studies are carried out with the monofunctional 1,1′-binaphthol-derived complex BINOL-AlCl. Graphical Abstract.
