- Evolution of N-Heterocycle-Substituted Iodoarenes (NHIAs) to Efficient Organocatalysts in Iodine(I/III)-Mediated Oxidative Transformations
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The reactivity of ortho-functionalized N-heterocycle-substituted iodoarenes (NHIAs) as organocatalysts in iodine(I/III)-mediated oxidations was systematically investigated in the α-tosyloxylation of ketones as the model reaction. During a systematic catalyst evolution, it was found that NH-triazoles and benzoxazoles have the most significant positive influence on the reactivity of the central iodine atom. A further catalyst improvement which focused on the substitution pattern of the arene revealed a remarkable ortho-effect. By introduction of an o-OMe group we were able to generate a novel NHIA with a so far unseen catalytic efficiency. This new catalyst is not only easy to synthesize but also enabled the α-tosyloxylation of carbonyl compounds at the lowest reported catalyst loading of only 1 mol%. Finally, the performance of this iodine(I) catalyst was successfully demonstrated in intramolecular oxidative couplings of biphenyls and oxidative rearrangements. (Figure presented.).
- Boelke, Andreas,Nachtsheim, Boris J.
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supporting information
p. 184 - 191
(2019/12/11)
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- Inexpensive NaX (X = I, Br, Cl) as a halogen donor in the practical Ag/Cu-mediated decarboxylative halogenation of aryl carboxylic acids under aerobic conditions
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Versatile and practical Ag/Cu-mediated decarboxylative halogenation between readily available aryl carboxylic acids and abundant NaX (X = I, Br, Cl) has been achieved under aerobic conditions in moderate to good yields. The halodecarboxylation is shown to be an effective strategy for S-containing heteroaromatic carboxylic acid and benzoic acids with nitro, chloro and methoxyl substituents at the ortho position. A gram-scale reaction and a three-step procedure to synthesize iniparib have been performed to evaluate the practicality of this protocol. A preliminary mechanistic investigation indicates that Cu plays a vital role and a radical pathway is involved in the transformation.
- Fu, Zhengjiang,Jiang, Ligao,Zuo, Qianming,Li, Zhaojie,Liu, Yanzhu,Wei, Zhenhong,Cai, Hu
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supporting information
p. 5416 - 5421
(2018/08/12)
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- Biphenyl-Based Bis(thiourea) Organocatalyst for Asymmetric and syn -Selective Henry Reaction
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A scalable, efficient and chromatography-free synthesis of a new enantiopure C 2-symmetric bis(thiourea) catalyst was accomplished from a readily available starting material. The developed strategy could be conducted on a multi-gram scale. Both the prepared enantiomers of the bis(thiourea) organocatalyst have been tested in the asymmetric Henry reaction under thoroughly optimized conditions during which an unusual solvent effect on enantioselectivity was found. The corresponding adducts were obtained in excellent yields with good to excellent enantioselectivities. The achieved high reactivity and enantioselectivity in the nitroaldol reaction of nitroalkanes with aromatic aldehydes suggests promising potential for this catalyst. Moreover, a significant syn-diastereoselectivity was observed.
- Otevrel, Jan,Bobal, Pavel
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p. 593 - 603
(2017/01/25)
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- Synthetic method of aryl halide taking aryl carboxylic acid as raw material
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A synthetic method of an aryl halide taking aryl carboxylic acid as a raw material is characterized in that a corresponding aryl halide is formed by carrying out substitution reaction on an aryl carboxylic acid compound and haloid salt MX in an organic solvent under the condition that oxygen, a silver catalyst, a copper additive and a bidentate nitrogen ligand exist, wherein M in MX represents alkali metal or alkaline earth metal, and X represents F, Cl, Br or I. Compared with a conventional aryl halide synthetic method, the synthetic method disclosed by the invention has the obvious advantages that reaction raw materials (comprising aryl carboxylic acid and MX) are cheap and easy to obtain, the using amount of a metal catalyst is small, pollution to the environment when the oxygen is used as an oxidant is the smallest, good tolerance to various functional groups on an aromatic ring is obtained, the yield is high, and the like. The synthetic method disclosed by the invention can be widely applied to synthesis in the fields of medicine, materials, natural products and the like in industry and academia.
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Paragraph 0118
(2018/01/03)
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- Axially Chiral Bifunctional 8,8′-Biquinolyl: Synthesis of 7,7′-Dihydroxymethyl-8,8′-biquinolyl via Pd-Catalyzed Double C-H Oxidation of 7,7′-Dimethyl-8,8′-biquinolyl
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Bifunctional C2-symmetric 7,7′-dihydroxymethyl-8,8′-biquinolyl (2) was synthesized in short steps via (i) Cu/Pd-catalyzed homo coupling of 7-methyl-8-bromoquinoline and (ii) Pd(II)-catalyzed double C-H oxidation. Axial chirality of 2 and its synthetic precursor 7,7′-dimethyl-8,8′-biquinolyl (3) is stable. Optically active 2 was obtained through separation of racemic 2 by chiral column HPLC or Pd(II)-catalyzed double C-H oxidation of optically active 3. The absolute stereochemistry of enantiomers of 2 and 3 was determined using the exciton chirality method.
- Kitamura, Mitsuru,Fukuma, Hiroaki,Kobayashi, Mitsuaki,Okayama, Shinya,Okauchi, Tatsuo
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p. 3956 - 3960
(2016/05/24)
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- Decarboxylative Halogenation and Cyanation of Electron-Deficient Aryl Carboxylic Acids via Cu Mediator as Well as Electron-Rich Ones through Pd Catalyst under Aerobic Conditions
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Simple strategies for decarboxylative functionalizations of electron-deficient benzoic acids via using Cu(I) as promoter and electron-rich ones by employing Pd(II) as catalyst under aerobic conditions have been established, which lead to smooth synthesis of aryl halides (-I, Br, and Cl) through the decarboxylative functionalization of benzoic acids with readily available halogen sources CuX (X = I, Br, Cl), and easy preparation of benzonitriles from decarboxylative cyanation of aryl carboxylic acids with nontoxic and low-cost K4Fe(CN)6 under an oxygen atmosphere for the first time.
- Fu, Zhengjiang,Li, Zhaojie,Song, Yuanyuan,Yang, Ruchun,Liu, Yanzhu,Cai, Hu
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p. 2794 - 2803
(2016/04/26)
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- Au-catalyzed formation of functionalized quinolines from 2-alkynyl arylazide derivatives
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A new method for converting 2-alkynyl arylazide derivatives into functionalized polysubstituted quinolines following a gold-catalyzed 1,3-acetoxy shift/cyclization/1,2-group shift sequence has been developed. This transformation proceeds under mild reaction conditions, is efficient, and tolerates a large variety of functional groups.
- Gronnier, Colombe,Boissonnat, Guillaume,Gagosz, Fabien
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supporting information
p. 4234 - 4237
(2013/09/12)
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- Syntheses and resolutions of new chiral biphenyl backbones: 2-Amino-2′-hydroxy-6,6′-dimethyl-1,1′-biphenyl and 2-amino-2′-hydroxy-4,4′,6,6′-tetramethyl-1,1′- biphenyl
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The new chiral backbones (R)-(+)- and S-(-)-2-amino-2′-hydroxy-6,6′-dimethyl-1,1′-biphenyl and (R)-(+)- and (S)-(-)-2-amino-2′-hydroxy-4,4′,6,6′- tetramethyl-1,1′-biphenyl were synthesized from o-methylaniline and 2,4-dimethyl-aniline respectively in seven steps. A new resolution method was developed to provide homochiral enantiomers (from diastereomeric salts) in reasonably high yields. The absolute configuration of the new biphenyls was confirmed by X-ray structural analysis.
- Liang, Yuxue,Gao, Shuang,Wan, Huihui,Wang, Junwei,Chen, Huilin,Zheng, Zhuo,Hu, Xinquan
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p. 1267 - 1273
(2007/10/03)
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- Enantioselective aziridination using copper complexes of biaryl Schiff bases
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Racemic 2,2′-diamino-6,6′-dimethylbiphenyl is resolved using simulated moving bed chromatography, and the absolute configuration of the enantiomers is confirmed via the X-ray crystal structure of a derivative. The diamine is condensed with a range of aldehydes to give bidentate aldimine proligands L. Molecular structures of the complexes formed between L and Cu(I) fall into two classes; bimetallic double helices ([Cu2L2]2+) and monometallic ([CuL]+). The latter are strikingly more efficient in the aziridination of alkenes than are the former in terms of rate, turnover, and enantioselection. In particular, the imine ligand formed from the diamine and 2,6-dichlorobenzaldehyde gives, in combination with Cu(I) or Cu(II), up to 99% ee in the aziridination of 6-acyl-2,2-dimethylchromene and 88-98% ee for a range of cinnamate esters. Styrenic and other alkenes are converted with lower selectivities (5-54%). The catalytic system shows a linear response in product ee to catalyst ee, and the product ee does not vary significantly during the reaction. UV spectrophotometric investigations indicate that conversion of Cu(I) to Cu(II) is not essential for catalysis but that Cu(II) is probably also a competent system.
- Gillespie, Kevin M.,Sanders, Christopher J.,O'Shaughnessy, Paul,Westmoreland, Ian,Thickitt, Christopher P.,Scott, Peter
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p. 3450 - 3458
(2007/10/03)
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- Synthesis and characterization of a superoxo complex of the dicobalt cofacial diporphyrin [(μ-O2)Co2(DPB)(1,5-diphenylimidazole) 2][PF6], the structure of the parent dicobalt diporphyrin Co2(DPB), and a new synthesis of the free-base cofacial diporphyrin H4(DPB)
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Chemical oxidation of the dicobalt cofacial diporphyrin Co2II/II(DPB), followed by exposure to dioxygen affords the bridged superoxo complex [(μ-O2)Co2(DPB)] [PF6]. This μ-superoxo complex has been implicated in possible mechanisms of four-electron dioxygen reduction by dicobalt cofacial diporphyrins but had not been isolated and fully-characterized previously. Although the superoxo complex is unstable with respect to loss of dioxygen, addition of 2 equiv of 1,5-diphenylimidazole yields [(μ-O2)Co2 III/III(DPB)(1,5-diphenylimidazole)2][PF6], a μ-superoxo complex that is stable toward loss of dioxygen. Analytically pure samples of the latter complex have been prepared, and their spectral and electrochemical properties are described. The crystal structure of the parent dicobalt cofacial diporphyrin Co2II/II(DPB) is reported. The Co-Co distance (3.726 (1) A?) and other structural features are compared to those of Co2(FTF4) and of other known metallo-DPB structures. A new, improved total synthesis of the free-base porphyrin H4(DPB) is presented. The combination of new reaction sequences, increased reaction scales, and improved product yields allows for large scale synthesis (gram quantities) of the free-base porphyrin needed to develop fully the coordination chemistry of the cofacial metallodiporphyrins.
- Collman, James P.,Hutchison, James E.,Lopez, Michel Angel,Tabard, Alain,Guilard, Roger,Seok, Won K.,Ibers, James A.,L'Her, Maurice
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p. 9869 - 9877
(2007/10/02)
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- Ruthenium-optically active phosphine complex
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A ruthenium-optically active phosphine complex having, as a ligand, BICHEP which means 2,2'-bis(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl represented by formula (I): STR1 is disclosed, which can catalyze asymmetric syntheses, such as asymmetric hydrogenation, asymmetric isomerization, and asymmetric silylation, exhibiting excellent catalytic activity and providing high optical purity.
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- Synthesis of Atropisomeric 2,2'-Bis(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl (BICHEP) and Its Use in Rh(I)-catalyzed Asymmetric Hydrogenation of Prochiral Olefins
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The atropisomeric bis(dialkylarylphosphine) ligands, (R)-(-)- and (S)-(+)-2,2'-bis(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl (BICHEP) (1) have been newly synthesized, whose Rh(I) complexes are highly efficient catalysts for asymmetric hydrogenations of ethyl α-(benzamido)cinnamate and dimethyl itaconate in up to 98percent yields and 98-99percent enantiomeric excess.
- Miyashita, Akira,Karino, Haruhiko,Shimamura, Jun-ichi,Chiba, Takeshi,Nagano, Katsuhiko,et al.
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p. 1849 - 1852
(2007/10/02)
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- Axially Dissymmetric Bis(triaryl)phosphines in the Biphenyl Series: Synthesis of (6,6'-Dimethylbiphenyl-2,2'-diyl)bis(diphenylphosphine) ('BIPHEMP') and Analogues, and their Use in Rh(I)-Catalyzed Asymmetric Isomerisations of N,N-Diethylnerylamine
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The axially dissymmetric diphosphines (-)-(R)- and (+)-(S)-(6,6'-dimethylbiphenyl-2,2'-diyl)bis(diphenylphosphine)((-)-(R)-10 and (+)-(S)-10; 'BIPHEMP') have been synthesized, starting from (R)- and (S)-6,6'-dimethylbiphenyl-2,2'-diamine ((R)- and (S)-16), respectively, via Sandmeyer reaction, lithiation, and phosphinylation.Moreover, racemic 4,4'-dimethyl- and 4,4'-bis(dimethylamino)-substituted analogues 11 and 12, respsctively, and the 6,6'-bridged analogue 1,11-bis(diphenylphosphino)-5,7-dihydrodibenzoxepin (13) were synthesized and resolved into optically pure (R)- and (S)-enantiomers via complexation with di-μ-chlorobisphenyl-C,N>dipalladium(II) ((R)-18).The molecular structures of the diphosphines (S)-10 and (R)-13 and of two derived cationic Rh(I) complexes, BF4 and BF4 were determined by X-ray analyses.Absolute configurations were established for (+)-(S)-10 by X-ray analyses of both the free diphosphine and of the derived Rh(I) complex, and for (-)-13 by X-ray analysis of the derived Rh(I) complex.Configurational assignments for the substituted BIPHEMP analogues 11 and 12 were achieved by means of 1H-NMR comparisons of the Pd(II) complexes derived from the diphosphines and (R)-18, and by means of CD comparisons.The BIPHEMP ligand 10 and analogues 11, 12, and 13 are the first examples of optically active bis(triarylphosphines) containing the axially dissymmetric biphenyl moiety.All these new diphosphines proved to be excellent asymmetry-inducing ligands in Rh(I)-catalyzed isomerizations of N,N-diethylnerylamine affording citronellal enamine of 98-99percent ee.
- Schmid, Rudolf,Cereghetti, Marco,Heiser, Bernd,Schoenholzer, Peter,Hansen, Hans-Juergen
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p. 897 - 930
(2007/10/02)
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- Preparation of Alkyl-Substituted Biphenylenes by the Pyrolytic Extrusion of Nitrogen from Benzocinnolines
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Flash vacuum pyrolysis of 1,10-dimethylbenzocinnoline (1a) at 730 deg C (0.12 Torr) provides 1,5-dimethylbiphenylene (6) in 71percent (53percent isolated) yield, whereas pyrolysis of 1,10-diethylbenzocinnoline (1b) produces a complex mixture containing some 1,8-diethylbiphenylene (8) (11.3percent) but more phenanthrene (9) (12.9percent) as well as a myriad of other side products.The preparation of the benzocinnolines and an investigation of the mechanism of phenanthrene formation are described.A straightforward correspondence between the mass spectrum of 1b and the pyrolysis pathway leading to phenanthrene is noted.The enhanced rates of side reactions in the pyrolysis of 1b are rationalized by estimating activation barriers for the processes competing with N2 extrusion and with ring closure.
- Wilcox, Charles F.,Lassila, Kevin R.,Kang, Steven
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p. 4333 - 4339
(2007/10/02)
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- Formation of Aryliodine(III) Derivatives in the Nitration of Aryl Iodides in Acetic Anhydride
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Nitration of iodobenzene, o-iodotoluene, and p-iodotoluene in acetic anhydride results in reversible oxidation to aryliodine(III) compounds prior to the formation of the expected nitro derivatives. μ-Oxo has been isolated from nitration of iodobenzene and its crystal structure determined.
- Bushnell, Gordon W.,Fischer, Alfred,Ibrahim, Prabha N.
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p. 1281 - 1286
(2007/10/02)
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- NEW ATROPISOMERIC CHIRAL BISPHOSPHINE, (S)-6,6'-DIMETHYL-2,2'-BIS(DIPHENYLPHOSPHINAMINO)BIPHENYL, AND ASYMMETRIC HYDROGENATION USING THE Rh(I) COMPLEX THEREOF
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Atropisomeric chiral bisphosphine, (S)-6,6'-dimethyl-2,2'-bis(diphenylphosphinamino)biphenyl (MABP) was newly prepared, and the Rh(I) complex thereof was found to be highly effective for the asymmetric hydrogenation of 2-acetamidoacrylic acid even under 1 atm of hydrogen pressure at a temperature below 0 deg C.
- Uehara, Akira,Kubota, Tohru,Tsuchiya, Ryokichi
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p. 441 - 444
(2007/10/02)
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- Indenylacetic acid compounds
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4, 5, 6 or 7 Aryl substituted indenyl acetic acids and pharmaceutically acceptable salts, amides and esters thereof. The 4, 5, 6 or 7 aryl substituted indenyl acetic acids have anti-inflammatory, anti-pyretic and analgesic activity. The invention also includes methods for the preparation of these compounds, pharmaceutical compositions and methods of treating inflammation by administering these particular compounds to patients.
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