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1.
Satish Koppireddi Joo‐Hyun Seo Eun‐Yeong Jeon Partha Sarathi Chowdhury Hyun‐Young Jang Jin‐Byung Park Yong‐Uk Kwon 《Advanced Synthesis \u0026amp; Catalysis》2016,358(19):3084-3092
A practical chemoenzymatic method for the synthesis of 9‐hydroxynonanoic acid and 1,9‐nonanedioic acid (i.e., azelaic acid) from oleic acid [(9Z)‐octadec‐9‐enoic acid] was investigated. Biotransformation of oleic acid into 9‐(nonanoyloxy)nonanoic acid via 10‐hydroxyoctadecanoic acid and 10‐keto‐octadecanoic acid was driven by a C‐9 double bond hydratase from Stenotrophomonas maltophilia, an alcohol dehydrogenase from Micrococcus luteus, and a Baeyer–Villiger monooxygenase (BVMO) from Pseudomonas putida KT2440, which was expressed in recombinant Escherichia coli. After production of the ester (i.e., the BVMO reaction product), the compound was chemically hydrolyzed to n‐nonanoic acid and 9‐hydroxynonanoic acid because n‐nonanoic acid is toxic to E. coli. The ester was also converted into 9‐hydroxynonanoic acid and the n‐nonanoic acid methyl ester, which can be oxygenated into the 9‐hydroxynonanoic acid methyl ester by the AlkBGT from P. putida GPo1. Finally, 9‐hydroxynonanoic acid was chemically oxidized to azelaic acid with a high yield under fairly mild reaction conditions. For example, whole‐cell biotransformation at a high cell density (i.e., 10 g dry cells/L) allowed the final ester product concentration and volumetric productivity to reach 25 mM and 2.8 mM h−1, respectively. The overall molar yield of azelaic acid from oleic acid was 58%, based on the biotransformation and chemical transformation conversion yields of 84% and 68%, respectively.
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Direct Access to Medium‐Chain α,ω‐Dicarboxylic Acids by Using a Baeyer–Villiger Monooxygenase of Abnormal Regioselectivity 下载免费PDF全文
Jia‐Mei Yu Yuan‐Yang Liu Yu‐Cong Zheng Hao Li Dr. Xiao‐Yan Zhang Dr. Gao‐Wei Zheng Dr. Chun‐Xiu Li Dr. Yun‐Peng Bai Prof. Jian‐He Xu 《Chembiochem : a European journal of chemical biology》2018,19(19):2049-2054
Baeyer–Villiger monooxygenases (BVMOs) are versatile biocatalysts in organic synthesis that can generate esters or lactones by inserting a single oxygen atom adjacent to a carbonyl moiety. The regioselectivity of BVMOs is essential in determining the ratio of two regioisomers for converting asymmetric ketones. Herein, we report a novel BVMO from Pseudomonas aeruginosa (PaBVMO); this has been exploited for the direct synthesis of medium‐chain α,ω‐dicarboxylic acids through a Baeyer–Villiger oxidation–hydrolysis cascade. PaBVMO displayed the highest abnormal regioselectivity toward a variety of long‐chain aliphatic keto acids (C16–C20) to date, affording dicarboxylic monoesters with a ratio of up to 95 %. Upon chemical hydrolysis, α,ω‐dicarboxylic acids and fatty alcohols are readily obtained without further treatment; this significantly reduces the synthetic steps of α,ω‐dicarboxylic acids from renewable oils and fats. 相似文献
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Zugui Shi Peiyuan Yu Pei Juan Chua Guofu Zhong 《Advanced Synthesis \u0026amp; Catalysis》2009,351(17):2797-2800
In the presence of the readily available quinine‐derived catalyst 4d , highly diastereo‐ and enantioselective Mannich reactions of tosyl‐protected imines and α‐isothiocyanato imides proceeded to afford the protected α,β‐diamino acids, useful building blocks for natural products and biologically active compounds, in good to excellent yields. 相似文献
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Semirational Protein Engineering of CYP153AM.aq.‐CPRBM3 for Efficient Terminal Hydroxylation of Short‐ to Long‐Chain Fatty Acids 下载免费PDF全文
Dr. Sandra Notonier Dr. Łukasz Gricman Prof. Dr. Jürgen Pleiss Prof. Dr. Bernhard Hauer 《Chembiochem : a European journal of chemical biology》2016,17(16):1550-1557
The regioselective terminal hydroxylation of alkanes and fatty acids is of great interest in a variety of industrial applications, such as in cosmetics, in fine chemicals, and in the fragrance industry. The chemically challenging activation and oxidation of non‐activated C?H bonds can be achieved with cytochrome P450 enzymes. CYP153AM.aq.‐CPRBM3 is an artificial fusion construct consisting of the heme domain from Marinobacter aquaeolei and the reductase domain of CYP102A1 from Bacillus megaterium. It has the ability to hydroxylate medium‐ and long‐chain fatty acids selectively at their terminal positions. However, the activity of this interesting P450 construct needs to be improved for applications in industrial processes. For this purpose, the design of mutant libraries including two consecutive steps of mutagenesis is demonstrated. Targeted positions and residues chosen for substitution were based on semi‐rational protein design after creation of a homology model of the heme domain of CYP153AM.aq., sequence alignments, and docking studies. Site‐directed mutagenesis was the preferred method employed to address positions within the binding pocket, whereas diversity was created with the aid of a degenerate codon for amino acids located at the substrate entrance channel. Combining the successful variants led to the identification of a double variant—G307A/S233G—that showed alterations of one position within the binding pocket and one position located in the substrate access channel. This double variant showed twofold increased activity relative to the wild type for the terminal hydroxylation of medium‐chain‐length fatty acids. This variant furthermore showed improved activity towards short‐ and long‐chain fatty acids and enhanced stability in the presence of higher concentrations of fatty acids. 相似文献
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Dominik Koszelewski Ivn Lavandera Dorina Clay David Rozzell Wolfgang Kroutil 《Advanced Synthesis \u0026amp; Catalysis》2008,350(17):2761-2766
Various ω‐transaminases were tested for the synthesis of enantiomerically pure amines from the corresponding ketones employing D ‐ or L ‐alanine as amino donor and lactate dehydrogenase to remove the side‐product pyruvate to shift the unfavourable reaction equilibrium to the product side. Both enantiomers, (R)‐ and (S)‐amines, could be prepared with up to 99% ee and >99% conversions within 24 h at 50 mM substrate concentration. The activity and stereoselectivity of the amination reaction depended on the ω‐transaminase and substrate employed; furthermore the co‐solvent significantly influenced both the stereoselectivity and activity of the transaminases. Best results were obtained by employing ATA‐117 to obtain the (R)‐enantiomer and ATA‐113 or ATA‐103 to access the (S)‐enantiomer with 15% v v−1 DMSO. 相似文献
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Manuel Weber Wolfgang Frey Ren Peters 《Advanced Synthesis \u0026amp; Catalysis》2012,354(8):1443-1449
Masked and activated highly enantioenriched α,α‐disubstituted α‐amino acids with an additional adjacent stereocenter were formed by a tandem reaction involving five steps using racemic unprotected amino acid substrates. Key step is the 1,4‐addition of in‐situ generated azlactones to a broad number of enones. The products of this step‐economic route can, e.g., be useful for a divergent and rapid access to biologically interesting unnatural glutamic acid derivatives. 相似文献
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Yan Jiang Xing Chen Xiao‐Yan Hu Chang Shu Yong‐Hong Zhang Yong‐Sheng Zheng Chun‐Xia Lian Wei‐Cheng Yuan Xiao‐Mei Zhang 《Advanced Synthesis \u0026amp; Catalysis》2013,355(10):1931-1936
The Lewis base‐organocatalyzed asymmetric hydrosilylation of α‐acetamido‐β‐enamino esters was investigated. Among various chiral Lewis base catalysts, a novel catalyst derived from L ‐serine was found to be the most efficient one which can promote the reaction to afford a series of α,β‐diamino acid derivatives with high yields (up to 99%), excellent enantioselectivities (up to 98% ee) and moderate diastereoselectivities (up to 80:20 dr). The absolute configuration of one of the products was determined by the X‐ray crystallographic analysis. In addition, the mechanism and the transition state of the reaction were proposed. 相似文献
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Benito Alcaide Pedro Almendros Sara Cembellín Teresa MartínezdelCampo 《Advanced Synthesis \u0026amp; Catalysis》2015,357(5):1070-1078
A novel, direct and simple methodology to gain access to α,β‐disubstituted conjugated enones from α‐allenols in a sustainable metal catalysis context, considering the inexpensiveness and environmentally friendliness of iron(III) species and protons, has been developed.
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Clemens Stueckler Christoph K. Winkler Mlanie Hall Bernhard Hauer Melanie Bonnekessel Klaus Zangger Kurt Faber 《Advanced Synthesis \u0026amp; Catalysis》2011,353(7):1169-1173
α,β‐Dehydroamino acid derivatives proved to be a novel substrate class for ene‐reductases from the ‘old yellow enzyme’ (OYE) family. Whereas N‐acylamino substituents were tolerated in the α‐position, β‐analogues were generally unreactive. For aspartic acid derivatives, the stereochemical outcome of the bioreduction using OYE3 could be controlled by variation of the N‐acyl protective group to furnish the corresponding (S)‐ or (R)‐amino acid derivatives. This switch of stereopreference was explained by a change in the substrate binding, by exchange of the activating ester group, which was proven by 2H‐labelling experiments. 相似文献
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Yanmei Liu Hua Lai Bo Rong Tie Zhou Jia Hong Chao Yuan Shujing Zhao Xiaolong Zhao Biao Jiang Qiang Fang 《Advanced Synthesis \u0026amp; Catalysis》2011,353(17):3161-3165
An efficient strategy for a high‐yielding and stereoselective synthesis of α‐trifluoromethyl unsaturated carboxylic acids directly from the reactions of 3,3,3‐trifluoropropanoic acid (CF3CH2COOH) with various aryl aldehydes in the presence of titanium tetrachloride (TiCl4) is reported here for the first time, which is a valuable expansion for the classical Knoevenagel reaction. Because these compounds may have potential applications in organic electronics and can be easily converted to the corresponding fluorinated alcohols and amino acids with excellent bioactivity, this route should be a good choice for the preparation of α‐trifluoromethyl‐containing derivatives. 相似文献
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Benito Alcaide Pedro Almendros Israel Fernndez Teresa Martínez del Campo Teresa Naranjo 《Advanced Synthesis \u0026amp; Catalysis》2013,355(13):2681-2685
α‐Allenols were catalytically transformed into dihydrofurans in the presence of platinum dichloride. Notably, using platinum dichloride along with silver triflate as the catalytic system, α,β‐unsaturated ketones were obtained. Therefore, the role of the silver salt may not just consist in the activation of the platinum precatalyst.
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Dieter Enders Katharina Gottfried Gerhard Raabe 《Advanced Synthesis \u0026amp; Catalysis》2010,352(18):3147-3152
The first organocatalytic enantioselective Strecker synthesis of α‐quaternary α‐trifluoromethylated amino acids has been developed. Employing Takemoto’s thiourea catalyst the nucleophilic addition of trimethylsilyl cyanide to trifluoromethyl ketimines affords α‐amino nitriles in good to excellent yields (50–99%) and very good enantioselectivities (ee=83–95%). The enantiopure amino nitriles can be obtained by recrystallization. Deprotection and hydrolysis leads to the title amino acids. 相似文献
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Jian Wang LoraD. Heikkinen Hao Li Liansuo Zu Wei Jiang Hexin Xie Wei Wang 《Advanced Synthesis \u0026amp; Catalysis》2007,349(7):1052-1056
A quinine‐promoted, enantioselective Michael addition reaction of diphenyl phosphite with nitroalkenes has been developed. This methodology affords a facile access to enantiomerically enriched β‐nitrophosphates, precursors for the preparation of synthetically and biologically useful β‐aminophosphonates. 相似文献
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Novel biodegradable chemically crosslinked polymers, poly(5‐hydroxylevulinic acid‐co‐α,ω‐diol)s (PHLA‐diols), were synthesized from 5‐hydroxylevulinic acid and α,ω‐diols and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. The gel content, swelling ratio, tensile properties, and hydrolytic degradation behaviors were also measured and assessed. The glass‐transition temperature of the PHLA‐diols could be adjusted within a wide range (?50 to 30°C) by the type and feed ratio of the diol. Because of the low glass‐transition temperature and crosslink structure, they exhibited certain elastic properties. The tensile modulus, strength, and elongation at break measured at 37°C were 1.4–6.3 MPa, 0.8–1.6 MPa, and 10–25%, respectively. These polymers could be hydrolytically degraded. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Sara Meninno Chiara Volpe Alessandra Lattanzi 《Advanced Synthesis \u0026amp; Catalysis》2016,358(17):2845-2848
A highly enantioselective one‐pot synthesis of important building blocks, α‐chiral γ‐keto esters, has been developed by combining a quinine‐catalyzed Michael addition of malononitrile to trans‐enones followed by magnesium monoperoxyphthalate (MMPP) oxidation. These synthons proved to be useful reagents for a simple access to challenging cis‐α,γ‐disubstituted γ‐butyrolactones in good diastereoselectivity and high enantiocontrol.
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Copper‐Catalyzed Addition of Alkylboranes to Iminoacetates: Access to α‐Alkyl Branched α‐Amino Acids
Xinsheng Xiao Wei Zhang Xiaoxia Lu Yuanfu Deng Huangfeng Jiang Wei Zeng 《Advanced Synthesis \u0026amp; Catalysis》2016,358(15):2497-2509
A copper(I)‐catalyzed addition of alkylborane reagents to α‐iminoacetates has been developed to assemble both acyclic and cyclic α‐branched α‐amino carboxylic acid derivatives in good yields. A wide variety of unactivated alkenes are well tolerated in this transformation.
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The enantio‐ and diastereoselective epoxidation of α,β‐unsaturated aldehydes in aqueous media was realized using a resin‐supported peptide catalyst. Introducing the hydrophobic and bulky unnatural amino acid 3‐(1‐pyrenyl)alanine into the peptide sequence was effective for enhancing the reaction rate and enantioselectivity. 相似文献