65487-97-0Relevant articles and documents
Cleavage of N-H Bond of Ammonia via Metal-Ligand Cooperation Enables Rational Design of a Conceptually New Noyori-Ikariya Catalyst
Dub, Pavel A.,Matsunami, Asuka,Kuwata, Shigeki,Kayaki, Yoshihito
, p. 2661 - 2677 (2019/02/14)
The asymmetric transfer hydrogenation (ATH) of ketones/imines with Noyori-Ikariya catalyst represents an important reaction in both academia and fine chemical industry. The method allows for the preparation of chiral secondary alcohols/amines with very good to excellent optical purities. Remarkably, the same chiral Noyori-Ikariya complex is also a precatalyst for a wide range of other chemo- and stereoselective reductive and oxidative transformations. Among them are enantioselective sulfonamidation of acrylates (intramolecular aza-Michael reaction) and carboxylation of indoles with CO2. Development of these catalytic reactions has been inspired by the realized cleavage of the N-H bond of sulfonamides and indoles by the 16e- amido derivative of the 18e- precatalyst via metal-ligand cooperation (MLC). This paper summarizes our efforts to investigate N-H bond cleavage of gaseous ammonia in solution via MLC and reports the serendipitous discovery of a new class of chiral tridentate I3[N,N′,N″] Ru and Ir metallacycles, derivatives of the famous M-FsDPEN catalysts (M = Ru, Ir). The protonation of these metallacycles by strong acids containing weakly coordinating (chiral) anions generates ionic complexes, which were identified as conceptually novel Noyori-Ikariya precatalysts. For example, the ATH of aromatic ketones with some of these complexes proceeds with up to 99% ee.
Probing the Effects of Heterocyclic Functionality in [(Benzene)Ru(TsDPENR)Cl] Catalysts for Asymmetric Transfer Hydrogenation
Barrios-Rivera, Jonathan,Xu, Yingjian,Wills, Martin
supporting information, p. 7223 - 7227 (2019/10/08)
A range of TsDPEN catalysts containing heterocyclic groups on the amine nitrogen atom were prepared and evaluated in the asymmetric transfer hydrogenation of ketones. Bidentate and tridentate ligands demonstrated a mutual exclusivity directly related to their function as catalysts. A broad series of ketones were reduced with these new catalysts, permitting the ready identification of an optimal catalyst for each substrate and revealing the subtle effects that changes to nearby donor groups can exhibit.
What to sacrifice? Fusions of cofactor regenerating enzymes with Baeyer-Villiger monooxygenases and alcohol dehydrogenases for self-sufficient redox biocatalysis
Mourelle-Insua, ángela,Aalbers, Friso S.,Lavandera, Iván,Gotor-Fernández, Vicente,Fraaije, Marco W.
, p. 1832 - 1839 (2019/02/24)
A collection of fusion biocatalysts has been generated that can be used for self-sufficient oxygenations or ketone reductions. These biocatalysts were created by fusing a Baeyer-Villiger monooxygenase (cyclohexanone monooxygenase from Thermocrispum municipale: TmCHMO) or an alcohol dehydrogenase (alcohol dehydrogenase from Lactobacillus brevis: LbADH) with three different cofactor regeneration enzymes (formate dehydrogenase from Burkholderia stabilis: BsFDH; glucose dehydrogenase from Sulfolobus tokodaii: StGDH, and phosphite dehydrogenase from Pseudomonas stutzeri: PsPTDH). Their tolerance against various organic solvents, including a deep eutectic solvent, and their activity and selectivity with a variety of substrates have been studied. Excellent conversions and enantioselectivities were obtained, demonstrating that these engineered fusion enzymes can be used as biocatalysts for the synthesis of (chiral) valuable compounds.
Chiral Ion-Pair Organocatalyst-Promoted Efficient Enantio-selective Reduction of α-Hydroxy Ketones
Zhang, Yiliang,He, Li,Shi, Lei
supporting information, p. 1926 - 1931 (2018/03/27)
The enantioselective reduction of α-hydroxy ketones with catecholborane has been developed employing 5 mol% of an 1,1′-bi-2-naphthol (BINOL)-derived ion-pair organocatalyst. This methodology provides a straightforward access to the corresponding aromatic 1,2-diols in high yields (up to 90%) with excellent enantioselectivities (up to 97%). Furthermore, the α-amino ketones also could be reduced with moderate ee values under mild reaction condition. (Figure presented.).
Zinc Acetate-Catalyzed Enantioselective Hydrosilylation of Ketones
Szewczyk, Marcin,Stanek, Filip,Bez?ada, Agata,Mlynarski, Jacek
supporting information, p. 3727 - 3731 (2016/01/25)
Zinc acetate complexes with a chiral diphenylethylenediamine (DPEDA)-derived ligand have been proved to be efficient catalysts for the enantioselective hydrosilylation of aryl ketones. Replacing pyrophoric dialkylzinc with the readily available zinc salt simplifies the procedures and provides excellent conversions (up to >99%) and enantioselectivities (ees up to 97%).
Asymmetric hydrosilylation of ketones catalyzed by zinc acetate with hindered pybox ligands
Lowicki, Daniel,Bezlada, Agata,Mlynarski, Jacek
supporting information, p. 591 - 595 (2014/05/20)
A highly efficient asymmetric hydrosilylation (AHS) of a wide variety of prochiral aryl ketones catalyzed by zinc acetate with TPS-he-pybox (tert-butyldiphenylsilyl hydroxyethyl pybox) ligand has been successfully developed. Cheap and readily available chiral Lewis acids based on zinc salts have been used as promising catalyst for the reduction of aryl ketones under mild conditions at room temperature leading to chiral alcohols in excellent yields and good to high enantioselectivities (up to 85% ee).
Microstructure analysis of a CO2 copolymer from styrene oxide at the diad level
Wu, Guang-Peng,Zu, Yu-Ping,Xu, Peng-Xiang,Ren, Wei-Min,Lu, Xiao-Bing
, p. 1854 - 1862 (2013/09/02)
A large amount of interesting information on the alternating copolymerization of CO2 with terminal epoxides has already been reported, such as the regiochemistry of epoxide ring-opening and the stereochemistry of the carbonate unit sequence in the polymer chain. Moreover, the microstructures of CO2 copolymers from propylene oxide and cyclohexene oxide have also been well-studied. However, the microstructure of the CO2 copolymer from styrene oxide (SO), an epoxide that contains an electron-withdrawing group, has not yet been investigated. Herein, we focus on the spectroscopic assignment of the CO2 copolymer from styrene oxide at the diad level by using three kinds of model dimer compounds, that is, T-T, H-T, and H-H. By comparing the signals in the carbonyl region, we concluded that the signals at δ=154.3, 153.8, and 153.3 ppm in the 13C NMR spectrum of poly(styrene carbonate) were due to tail-to-tail, head-to-tail, and head-to-head carbonate linkages, respectively. Moreover, various isotactic and syndiotactic model compounds based on T-T, H-T, and H-H (dimers (R,R)-T-T, (S,S)-T-T, and (R,S)-T-T; (R,R)-H-T, (S,S)-H-T, and (R,S)-H-T; (R,R)-H-H, (S,S)-H-H, and (R,S)-H-H) were synthesized for the further spectroscopic assignment of stereospecific poly(styrene carbonate)s. We found that the carbonate carbon signals were sensitive towards the stereocenters on adjacent styrene oxide ring-opening units. These discoveries were found to be well-matched to the microstructures of the stereoregular poly(styrene carbonate)s that were prepared by using a multichiral CoIII-based catalyst system. T-T races: The spectroscopic assignment of regio- and stereoregular poly(styrene carbonate)s at the diad level was performed by 13C NMR studies of three kinds of model compounds, as well as their syndiotactic (R,S) and isotactic (R,R or S,S) dimers. Copyright
Asymmetric synthesis of β-adrenergic blockers through multistep one-pot transformations involving in situ chiral organocatalyst formation
Wei, Shengwei,Messerer, Regina,Tsogoeva, Svetlana B.
supporting information; scheme or table, p. 14380 - 14384 (2012/02/01)
Two birds one stone: A new atom-economical one-pot approach to enantioselective chiral drug synthesis, involving in situ multistep organocatalyst formation and the application of the reaction for multistep sequential synthesis of β-adrenergic blockers is disclosed (see scheme).
Copper-Catalyzed enantioselective hydrosilylation of ketones by using monodentate binaphthophosphepine ligands
Junge, Kathrin,Wendt, Bianca,Addis, Daniele,Zhou, Shaolin,Das, Shoubhik,Beller, Matthias
experimental part, p. 68 - 73 (2010/03/03)
"Chemical Equation Presented" No base required: The first copper-catalyzed asymmetric hydrosilylation of carbonyl compounds by using monodentate binaphthophosphepine ligands is presented. After optimization of the reaction parameters, high yields and enantioselectivities (up to 96 % ee) for a broad range of aryl alkyl, cyclic, heterocyclic and aliphatic ketones are achieved without a base.
