177723-18-1Relevant articles and documents
Enantioselective Strecker reaction promoted by chiral N-oxides
Liu,Feng,Chen,Zhang,Cui,Jiang
, p. 1551 - 1554 (2001)
The asymmetric Strecker reaction of aldimines and trimethylsilyl cyanide promoted by 1 equivalent of chiral N-oxide affords the corresponding α-amino nitriles with enantioselectivities of up to 73% most effectively for electron-deficient aldimines under m
A new approach to enantioselective cyanation of imines with Et 2AlCN
Nakamura, Shuichi,Sato, Naoki,Sugimoto, Masashige,Toru, Takeshi
, p. 1513 - 1516 (2004)
An enantioselective Strecker-type reaction of imines with Et 2AlCN in the presence of chiral additives has been examined. The enantioselectivity varied depending on the substituents of the imino group as well as the chiral additives used. Thus, α-aminonitriles were obtained in good yields with good enantioselectivities in the reaction of N-benzylidenebenzhydrylamine with Et2AlCN and BINOL. The reaction with excess BINOL gave the aminonitrile with reversed configuration.
Enantioselective Strecker reactions between aldimines and trimethylsilyl cyanide promoted by chiral N,N′-dioxides
Jiao, Zhigang,Feng, Xiaoming,Liu, Bo,Chen, Fuxue,Zhang, Guolin,Jiang, Yaozhong
, p. 3818 - 3826 (2003)
Axially chiral N,N′-dioxide Lewis base promoters have been developed and have for the first time been applied to the asymmetric synthesis of α-amino nitriles through cyanide addition to aldimines. The chiral 3,3′-dimethyl-2,2′-biquinoline N,N′-dioxide 2 exhibited high enantioselectivity for asymmetric Strecker reactions between N-benzhydrylimines and trimethylsilyl cyanide. In the presence of 1 equiv. of chiral promoter 2, the cyanosilylation of aldimines afforded the corresponding α-amino nitriles with ee values of up to 95%. Optically pure products (99% ee) were obtained simply by recrystallization in the cases of some of the products. Moreover, the promoter 2 could be recovered and reused at least four times without any loss of enantioselectivity and reactivity. A putative mechanism for the enantioselective Strecker reactions is also discussed. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
Enantioselective synthesis of α-amino nitriles from N-benzhydryl imines and HCN with a chiral bicyclic guanidine as catalyst
Corey,Grogan, Michael J.
, p. 157 - 160 (1999)
(Equation Presented) A novel catalytic enantioselective Strecker synthesis of chiral α-amino nitriles and α-amino acids is described and analyzed with regard to the possible mechanistic basis for stereoselectivity. Key features of the enantioselective process include (1) the use of the chiral bicyclic guanidine 1 as catalyst and (2) the use of the N-benzhydryl substituent on the imine substrate.
Mechanism of enantioselective Ti-catalyzed strecker reaction: Peptide-based metal complexes as bifunctional catalysts
Josephsohn,Kuntz,Snapper,Hoveyda
, p. 11594 - 11599 (2001)
Kinetic, structural, and stereochemical data regarding the mechanism of Ti-catalyzed addition of cyanide to imines in the presence of Schiff base peptide ligands are disclosed. The reaction is first order in the Ti·ligand complex; kinetic studies reveal Δ
Enantioselective Reductive Cyanation and Phosphonylation of Secondary Amides by Iridium and Chiral Thiourea Sequential Catalysis
Chen, Dong-Huang,Sun, Wei-Ting,Zhu, Cheng-Jie,Lu, Guang-Sheng,Wu, Dong-Ping,Wang, Ai-E,Huang, Pei-Qiang
supporting information, p. 8827 - 8831 (2021/03/16)
The combination of transition-metal catalysis and organocatalysis increasingly offers chemists opportunities to realize diverse unprecedented chemical transformations. By combining iridium with chiral thiourea catalysis, direct enantioselective reductive cyanation and phosphonylation of secondary amides have been accomplished for the first time for the synthesis of enantioenriched chiral α-aminonitriles and α-aminophosphonates. The protocol is highly efficient and enantioselective, providing a novel route to the synthesis of optically active α-functionalized amines from the simple, readily available feedstocks. In addition, the reactions are scalable and the thiourea catalyst can be recycled and reused.
Enantioselective Strecker reaction of aldimines using potassium cyanide catalyzed by a recyclable macrocyclic V(v) salen complex
Saravanan,Khan, Noor-Ul H.,Jakhar, Ajay,Ansari, Amamudin,Kureshy, Rukhsana I.,Abdi, Sayed H. R.,Kumar, Gaurav
, p. 99951 - 99958 (2015/12/04)
A chiral dimeric macrocyclic V(v) salen complex based on a chiral macrocyclic salen ligand derived from 1R, 2R-(-) diaminocyclohexane with trigol bisaldehyde was synthesized and evaluated as an efficient catalyst (5 mol%) for asymmetric addition of potass
Oxazoline-based organocatalyst for enantioselective strecker reactions: A protocol for the synthesis of levamisole
Sadhukhan, Arghya,Sahu, Debashis,Ganguly, Bishwajit,Khan, Noor-Ul H.,Kureshy, Rukhsana I.,Abdi, Sayed H.R.,Suresh,Bajaj, Hari C.
, p. 14224 - 14232 (2013/11/06)
A chiral oxazoline-based or-ganocatalyst has been found to efficiently catalyze asymmetric Strecker reactions of various aromatic and aliphatic N-benzhydrylimines with trime-thylsilyl cyanide (TMSCN) as a cyanide source at -20°C to give α-aminoni-triles in high yield (96%) with excellent chiral induction (up to 98% ee). DFT calculations have been performed to rationalize the enantioselective formation of the product with the organo-catalyst in these reactions. The organo-catalyst has been characterized by single-crystal X-ray diffraction analysis, as well as by other analytical methods. This protocol has been extended to the synthesis of the pharmaceutically important drug molecule levamisole in high yield and with high enantioselectivity.
Self-supported chiral titanium cluster (SCTC) as a robust catalyst for the asymmetric cyanation of imines under batch and continuous flow at room temperature
Seayad, Abdul M.,Ramalingam, Balamurugan,Chai, Christina L. L.,Li, Chuanzhao,Garland, Marc V.,Yoshinaga, Kazuhiko
, p. 5693 - 5700 (2012/06/15)
A robust heterogeneous self-supported chiral titanium cluster (SCTC) catalyst and its application in the enantioselective imine-cyanation/Strecker reaction is described under batch and continuous processes. One of the major hurdles in the asymmetric Strecker reaction is the lack of availability of efficient and reusable heterogeneous catalysts that work at room temperature. We exploited the readily hydrolyzable nature of titanium alkoxide to synthesize a self-supported chiral titanium cluster (SCTC) catalyst by the controlled hydrolysis of a preformed chiral titanium-alkoxide complex. The isolated SCTC catalysts were remarkably stable and showed up to 98% enantioselectivity (ee) with complete conversion of the imine within 2 h for a wide variety of imines at room temperature. The heterogeneous catalysts were recyclable more than 10 times without any loss in activity or selectivity. The robustness, high performance, and recyclability of the catalyst enabled it to be used in a packed-bed reactor to carry out the cyanation under continuous flow. Up to 97% ee and quantitative conversion with a throughput of 45 mgh-1 were achieved under optimized flow conditions at room temperature in the case of benzhydryl imine. Furthermore, a three-component Strecker reaction was performed under continuous flow by using the corresponding aldehydes and amines instead of the preformed imines. A good product distribution was obtained for the formation of amino nitriles with ee values of up to 98%. Synthetically useful ee values were also obtained for challenging α-branched aliphatic aldehyde by using the three-component continuous Strecker reaction.
Highly enantioselective titanium-catalyzed cyanation of imines at room temperature
Seayad, Abdul Majeed,Ramalingam, Balamurugan,Yoshinaga, Kazuhiko,Nagata, Takushi,Chai, Christina L. L.
scheme or table, p. 264 - 267 (2010/03/24)
(Figure presented) A highly active and enantioselective titanium-catalyzed cyanatlon of imines at room temperature Is described. The catalyst used Is a partially hydrolyzed titanium alkoxide (PHTA) precatalyst together with a readily available N-salicyl-β-aminoalcohol ligand. Up to 98% ee was obtained with quantitative yields In 15 min of reaction time using 5 mol % of the catalyst. Various N-protecting groups such as benzyl, benzhydryl, Boc, and PMP are tolerated.
