- Cationic Iridium-Catalyzed Asymmetric Decarbonylative Aryl Addition of Aromatic Aldehydes to Bicyclic Alkenes
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We report an unprecedented catalytic protocol for the enantioselective decarbonylative transformation of aryl aldehydes. In this process, the decarbonylation of aldehydes catalyzed by chiral iridium complexes enabled the formation of asymmetric C?C bonds
- Nonami, Reina,Morimoto, Yusei,Kanemoto, Kazuya,Yamamoto, Yasunori,Shirai, Tomohiko
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- Biocatalytic reduction of α,β-unsaturated carboxylic acids to allylic alcohols
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We have developed robust in vivo and in vitro biocatalytic systems that enable reduction of α,β-unsaturated carboxylic acids to allylic alcohols and their saturated analogues. These compounds are prevalent scaffolds in many industrial chemicals and pharmaceuticals. A substrate profiling study of a carboxylic acid reductase (CAR) investigating unexplored substrate space, such as benzo-fused (hetero)aromatic carboxylic acids and α,β-unsaturated carboxylic acids, revealed broad substrate tolerance and provided information on the reactivity patterns of these substrates. E. coli cells expressing a heterologous CAR were employed as a multi-step hydrogenation catalyst to convert a variety of α,β-unsaturated carboxylic acids to the corresponding saturated primary alcohols, affording up to >99percent conversion. This was supported by the broad substrate scope of E. coli endogenous alcohol dehydrogenase (ADH), as well as the unexpected CC bond reducing activity of E. coli cells. In addition, a broad range of benzofused (hetero)aromatic carboxylic acids were converted to the corresponding primary alcohols by the recombinant E. coli cells. An alternative one-pot in vitro two-enzyme system, consisting of CAR and glucose dehydrogenase (GDH), demonstrates promiscuous carbonyl reductase activity of GDH towards a wide range of unsaturated aldehydes. Hence, coupling CAR with a GDH-driven NADP(H) recycling system provides access to a variety of (hetero)aromatic primary alcohols and allylic alcohols from the parent carboxylates, in up to >99percent conversion. To demonstrate the applicability of these systems in preparative synthesis, we performed 100 mg scale biotransformations for the preparation of indole-3-aldehyde and 3-(naphthalen-1-yl)propan-1-ol using the whole-cell system, and cinnamyl alcohol using the in vitro system, affording up to 85percent isolated yield.
- Aleku, Godwin A.,Leys, David,Roberts, George W.
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p. 3927 - 3939
(2020/07/09)
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- Asymmetric synthesis of isoquinolinonaphthyridines catalyzed by a chiral Br?nsted acid
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A catalytic asymmetric method for the synthesis of chiral isoquinolinonaphthyridines has been developed. A chiral disulfonimide catalyzes a redox cyclization reaction between 2-methyl-3-aldehydeazaarenes and 1,2,3,4-tetrahydroisoquinolines to deliver a range of isoquinolinonaphthyridines with good to high yields (up to 91%) and up to 92:8 er.
- Li, Jianjun,Fu, Yiwei,Qin, Cong,Yu, Yang,Li, Hao,Wang, Wei
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p. 6474 - 6477
(2017/08/16)
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- Near-infrared-emitting iridium(III) complexes as phosphorescent dyes for live cell imaging
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The three near-infrared-emitting cationic iridium(III) complexes [Ir(pbq-g)2(NaN)]+PF 6- (pbq-g = phenylbenzo[g]quinoline; N aN = bipyridine (1), 1,10-phenanthroline (2), 4,7-diphenyl-1,10-phenanthroline (3)) have been demonstrated as phosphorescent dyes in live cell imaging. These complexes with different ancillary ligands show similar near-infrared (NIR) emission with λmax,peak at 698 nm and λmax,shoulder at 760 nm in CH2Cl2 solutions, with a moderate quantum yield of around 3%. However, these complexes behave quite differently as NIR dyes for live cell imaging. Complexes 1 and 2 exhibit exclusive staining in the cytoplasm with good cell membrane permeability under excitation at 488 nm, while 3 gives almost no cell uptake, as further determined by flow cytometry. Although the lipophilicities of these complexes follow the order 1 a key role in the design of NIR-emitting iridium(III) complexes for practical applications in bioimaging.
- Zhang, Guoliang,Zhang, Huiyuan,Gao, Yuan,Tao, Ran,Xin, Lijun,Yi, Junyang,Li, Fuyou,Liu, Wanli,Qiao, Juan
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- Synthesis and spectral properties of Azahetero-aromatic derivatives of 2-styrylanthracene
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Novel azaheteroaromatic derivatives of 2-styrylanthracene: 2-styrylbenzo[g]quinoline and 3-styryl- acridine were obtained from 3-nitro-2-naphthaldehyde and 2-bromo-4-methylbenzoic acid. Spectral properties of the new compounds were studied.
- Lee,Budyka
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p. 1477 - 1481
(2013/04/10)
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- Synthesis and Properties of Ligands Based on Benzoquinoline
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The preparation of 3-amino-2-naphthaldehyde is described.Ammonolysis of 3-hydroxy-2-naphthoic acid affords the corresponding amino acid which can be esterified and then reduced with LAH.Protection of the amino group, MnO2 oxidation of the primary alcohol to an aldehyde, and deprotection gave the amino aldehyde which is an excellent Friedlaender synthon for benzoquinolines.Dimethylene-bridged analogues of 2,2'-bipyridine and 2,2';6,2''-terpyridine were prepared as well as orthocyclophanes derived from tetracyclo4,11.05,9>undecane-2,7-dione (TCU-2,7-dione).The absorption and emission spectra of these species are consistent with the parent benzoquinoline where bathochromic shifts result from increased delocalization.The TCU derivative evidences exciplex formation so that its benzoquinoline emission is almost completely quenched and an exciplex emission appears at 525 nm.Electrochemical analysis indicates that both reduction and UV absorption involve the same ?* orbital.
- Taffarel, Emmanuelle,Chirayil, Sarah,Thummel, Randolph P.
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p. 823 - 828
(2007/10/02)
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