53732-47-1Relevant articles and documents
Ultrasound-promoted lipase-catalyzed reactions
Lin, Gialih,Liu, Hsiao-Chien
, p. 6067 - 6068 (1995)
Lipase from porcine pancreas is first demonstrated to catalyze reactions under ultrasonic condition. Reaction rates are significantly enhanced 7 to 83-fold and enantioselectivities are retained.
Engineering a Carbonyl Reductase as a Potential Tool for the Synthesis of Chiral α-Tetralinols
Li, Aipeng,Ting, Wang,Yang, Ke,Zhang, Xuanshuo,Yin, Dongming,Qin, Yong,Zhang, Lianbing
, p. 4625 - 4633 (2021)
Tailoring of enzyme toward α-tetralones, a class of bulky-bulky ketones, is still a challenge. In this work, the mutants of carbonyl reductase BaSDR1 with improved catalytic performance toward α-tetralone 1 a were obtained by adjusting the steric hindrance and hydrophobicity of the residues that affect the approach of α-tetralone with the catalytic residues. The designed mutants also showed enhanced catalytic performance toward halogenated α-tetralones 2 a–6 a. Remarkably, the activity of the mutant Q237V/I291F toward 7-fluoro-α-tetralone 5 a was 16.3-fold higher than the wildtype enzyme with improved stereoselectivity (98.8 % ee). More notably, the mutants Q139S and Q139S/V187S exhibited decreased or reversed stereoselectivity toward α-tetralone 1 a, 5-bromo-α-tetralone 2 a, 7-fluoro-α-tetralone 5 a and 7-chloro-α-tetralone 6 a, while the relatively high ee values were obtained in the presence of 6-chloro-α-tetralone 3 a and 6-bromo-α-tetralone 4 a as substrates. Further analysis showed the larger size of the substrates was beneficial for the substrates binding to the active cavity with a more specific binding mode, which endows the reaction with higher stereoselectivity. Moreover, the recombinant E. coli expressing the variant Q237V/I291F successfully catalyzed the reduction of a high concentration 7-fluoro-α-tetralone 5 a. These results not only offered a potential tool for chiral α-tetralols, but also provided guiding information for the enzyme engineering toward bulky-bulky ketones.
Designer Outer Membrane Protein Facilitates Uptake of Decoy Molecules into a Cytochrome P450BM3-Based Whole-Cell Biocatalyst
Karasawa, Masayuki,Shoji, Osami,Stanfield, Joshua Kyle,Suzuki, Kazuto,Yonemura, Kai
supporting information, (2021/12/16)
We report an OmpF loop deletion mutant, which improves the cellular uptake of external additives into an Escherichia coli whole-cell biocatalyst. Through co-expression of the OmpF mutant with wild-type P450BM3 in the presence of decoy molecules, the yield
Ru-catalyzed mechanochemical asymmetric transfer hydrogenations in aqueous media using chitosan as chirality source
Kolcsár, Vanessza Judit,Sz?ll?si, Gy?rgy
, (2022/02/09)
As the demand for sustainable methods increases, synthetic chemistry is focusing on the application of environmentally benign methods, such as fast reactions induced by alternative energy transmission. Chitosan is a chiral biopolymer of natural origin, which can be used in asymmetric catalysis. The application of Ru-chitosan complexes along with the mechanochemical activation may open great opportunities for sustainable preparation of optically pure alcohols. In the present study, we optimized the mechanochemical asymmetric transfer hydrogenation of 4-chromanone, carried out in a mixing mill. The reaction was catalyzed by the in situ formed Ru-chitosan complex, applying HCOONa as the hydrogen donor in aqueous media. We examined the mechanical effects of different grinding media sizes, then explored the scope of the system using 24 prochiral ketones, which ranged from hetero- and carbocyclic ketones to acetophenone derivatives. In most of the cases, the reactions were successfully scaled up to 1 mmol and the products were isolated in good yields and outstanding enantioselectivities. Our present study is a significant step forward to the development of environmentally benign and sustainable enantioselective processes, as the alternative activation method provided optically enriched alcohols using a biodegradable chirality source in aqueous media.
A NEW TEMPLATE of MITSUNOBU ACYLATE CLEAVABLE in NONALKALINE CONDITIONS
Sai, Yusuke,Sakakibara, Yoshimichi,Shigetomi, Kengo,Ubukata, Makoto,Uraki, Yasumitsu
, p. 140 - 158 (2022/01/08)
The Mitsunobu inversion is one of the reliable methods for stereospecific substitution of chiral alcohols, but its deacylation step has limited the substrate scope. Here, we propose a new template of the Mitsunobu acylate that can be deacylated in non-alkaline treatments. The 3,4-dihydroxy-2-methylenebutanoate was selected as a template structure, and its acetonide- or bisTBS derivatives were synthesized. The latter especially showed excellent inversion efficiency (up to >99% ee) and good elimination performance for a series of secondary alcohols in near-neutral conditions. The results demonstrated the applicability of the new template for the substrates labile in alkaline conditions, such as a-hydroxyesters.
Dynamic Kinetic Resolution of Alcohols by Enantioselective Silylation Enabled by Two Orthogonal Transition-Metal Catalysts
Oestreich, Martin,Seliger, Jan
supporting information, p. 247 - 251 (2020/10/29)
A nonenzymatic dynamic kinetic resolution of acyclic and cyclic benzylic alcohols is reported. The approach merges rapid transition-metal-catalyzed alcohol racemization and enantioselective Cu-H-catalyzed dehydrogenative Si-O coupling of alcohols and hydrosilanes. The catalytic processes are orthogonal, and the racemization catalyst does not promote any background reactions such as the racemization of the silyl ether and its unselective formation. Often-used ruthenium half-sandwich complexes are not suitable but a bifunctional ruthenium pincer complex perfectly fulfills this purpose. By this, enantioselective silylation of racemic alcohol mixtures is achieved in high yields and with good levels of enantioselection.
Chiral Yolk-Shell MOF as an Efficient Nanoreactor for Asymmetric Catalysis in Organic-Aqueous Two-Phase System
Shi, Shunli,Zhong, Yicheng,Hu, Zhuo,Wang, Lei,Yuan, Mingwei,Ding, Shunmin,Wang, Shuhua,Chen, Chao
supporting information, p. 12714 - 12718 (2021/09/11)
It remains a great challenge to introduce large and efficient homogeneous asymmetric catalysts into MOFs and other microporous materials as well as retain their degrees of freedom. Herein, a new heterogeneous strategy of homogeneous chiral catalysts is proposed, that is, to construct a yolk-shell MOFs-confined, large-size, and highly efficient homogeneous chiral catalyst, which can be used as a nanoreactor for asymmetric catalytic reactions.
Phase Separation-Promoted Redox Deracemization of Secondary Alcohols over a Supported Dual Catalysts System
Zhao, Zhitong,Wang, Chengyi,Chen, Qipeng,Wang, Yu,Xiao, Rui,Tan, Chunxia,Liu, Guohua
, p. 4055 - 4063 (2021/08/12)
Unification of oxidation and reduction in a one-pot deracemization process has great significance in the preparation of enantioenriched organic molecules. However, the intrinsic mutual deactivation of oxidative and reductive catalysts and the extrinsic incompatible reaction conditions are unavoidable challenges in a single operation. To address these two issues, we develop a supported dual catalysts system to overcome these conflicts from incompatibility to compatibility, resulting in an efficient one-pot redox deracemization of secondary alcohols. During this transformation, the TEMPO species onto the outer surface of silica nanoparticles catalyze the oxidation of racemic alcohols to ketones, and the chiral Rh/diamine species in the nanochannels of the thermoresponsive polymer-coated hollow-shell mesoporous silica enable the asymmetric transfer hydrogenation (ATH) of ketones to chiral alcohols. To demonstrate the general feasibility, a series of orthogonal oxidation/ATH cascade reactions are compared to prove the compatible benefits in the elimination of their deactivations and the balance of the cascade directionality. As presented in this study, this redox deracemization process provides various chiral alcohols with enhanced yields and enantioselectivities relative to those from unsupported dual catalysts systems. Furthermore, the dual catalysts can be recycled continuously, making them an attractive feature in the application.
Enantioselective direct, base-free hydrogenation of ketones by a manganese amido complex of a homochiral, unsymmetrical P-N-P′ ligand
Seo, Chris S. G.,Tsui, Brian T. H.,Gradiski, Matthew V.,Smith, Samantha A. M.,Morris, Robert H.
, p. 3153 - 3163 (2021/05/25)
The use of manganese in homogeneous hydrogenation catalysis has been a recent focus in the pursuit of more environmentally benign base metal catalysts. It has great promise with its unique reactivity when coupled with metal-ligand cooperation of aminophosphine pincer ligands. Here, a manganese precatalyst Mn(P-N-P′)(CO)2, where P-N-P′ is the amido form of the ligand (S,S)-PPh2CHPhCHPhNHCH2CH2PiPr2, has been synthesized and used for base-free ketone hydrogenation. This catalyst shows exceptionally high enantioselectivity and good activity, with tolerance for base-sensitive substrates. NMR structural analysis of intermediates formed by the reaction of the amido complex with hydrogen under pressure identified a reactive hydride with an NOE contact with the syn amine proton. Computational analysis of the catalytic cycle reveals that the heterolytic splitting of dihydrogen across the MnN bond in the amido complex has a low barrier while the hydride transfer to the ketone is the turnover-limiting step. The pro-S transition state is found to be usually much lower in energy than the pro-R transition state depending on the ketone structure, consistent with the high (S) enantiomeric excess in the alcohol products. The energy to reach the transition state is higher for the distortion of the in-coming ketone than that of the hydride complex. In a one-to-one comparison with the similar iron catalyst FeH2(CO)(P-NH-P′), the manganese catalyst is found to have higher enantioselectivity, often over 95% ee, while the iron catalyst has higher activity and productivity. An explanation of these differences is provided on the basis of the more deformable iron hydride complex due to the smaller hydride ligands.
Homochiral Dodecanuclear Lanthanide "cage in Cage" for Enantioselective Separation
Zhu, Chengfeng,Tang, Haitong,Yang, Keke,Fang, Yu,Wang, Kun-Yu,Xiao, Zhifeng,Wu, Xiang,Li, Yougui,Powell, Joshua A.,Zhou, Hong-Cai
supporting information, p. 12560 - 12566 (2021/08/23)
It is extremely difficult to anticipate the structure and the stereochemistry of a complex, particularly when the ligand is flexible and the metal node adopts diverse coordination numbers. When trivalent lanthanides (LnIII) and enantiopure amino acid ligands are utilized as building blocks, self-assembly sometimes yields rare chiral polynuclear structures. In this study, an enantiopure carboxyl-functionalized amino acid-based ligand with C3 symmetry reacts with lanthanum cations to give a homochiral porous coordination cage, (Δ/λ)12-PCC-57. The dodecanuclear lanthanide cage has an unprecedented octahedral "cage-in-cage"framework. During the self-assembly, the chirality is transferred from the enantiopure ligand and fixed by the binuclear lanthanide cluster to give 12 metal centers that have either Δor λ homochiral stereochemistry. The cage exhibits excellent enantioselective separation of racemic alcohols, 2,3-dihydroquinazolinones, and multiple commercially available drugs. This finding exhibits a rare example of a multinuclear lanthanide complex with a dual-walled topology and homochirality. The highly ordered self-assembly and self-sorting of flexible amino acids and lanthanides shed light on the chiral transformation between different complicated artificial systems that mimic natural enzymes.
