- Aerobic Copper-Catalyzed Salicylaldehydic Cformyl?H Arylations with Arylboronic Acids
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We report a challenging copper-catalyzed Cformyl?H arylation of salicylaldehydes with arylboronic acids that involves unique salicylaldehydic copper species that differ from reported salicylaldehydic rhodacycles and palladacycles. This protocol has high chemoselectivity for the Cformyl?H bond compared to the phenolic O?H bond involving copper catalysis under high reaction temperatures. This approach is compatible with a wide range of salicylaldehyde and arylboronic acid substrates, including estrone and carbazole derivatives, which leads to the corresponding arylation products. Mechanistic studies show that the 2-hydroxy group of the salicylaldehyde substrate triggers the formation of salicylaldehydic copper complexes through a CuI/CuII/CuIII catalytic cycle.
- Xiao, Lin,Lang, Tao-Tao,Jiang, Ying,Zang, Zhong-Lin,Zhou, Cheng-He,Cai, Gui-Xin
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supporting information
p. 3278 - 3283
(2021/02/01)
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- Asymmetric Transfer Hydrogenation of o-Hydroxyphenyl Ketones: Utilizing Directing Effects That Optimize the Asymmetric Synthesis of Challenging Alcohols
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A systematic range of o-hydroxyphenyl ketones were reduced under asymmetric transfer hydrogenation conditions using the C3-tethered catalyst 2. Two directing effects, i.e., an o-hydroxyphenyl coupled to a bulky aromatic on the opposite side of the ketone substrate, combine in a matched manner to deliver reduction products with very high enantiomeric excess.
- Clarkson, Guy J.,Wills, Martin,Zheng, Ye
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- Efficient visible-light photocatalytic aerobic oxidation of cyclic sulfamides to imines
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A highly efficient photocatalytic aerobic oxidation of cyclic sulfamides to synthesize cyclic N-sulfonyl imines with Ir(ppy)2(dtbpy)PF6 as photocatalyst is reported. These environmentally friendly transformations exihibit good to excellent isolated yields and good generality with respect to both five-membered and six-membered cyclic sulfamides.
- Ming, Zong-Yao,Li, Kang-Rui,Meng, Fan-Jie,Shi, Lei,Jiang, Wen-Feng
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supporting information
(2020/06/17)
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- Ruthenium-Catalyzed Direct Asymmetric Reductive Amination of Diaryl and Sterically Hindered Ketones with Ammonium Salts and H2
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A Ru-catalyzed direct asymmetric reductive amination of ortho-OH-substituted diaryl and sterically hindered ketones with ammonium salts is reported. This method represents a straightforward route toward the synthesis of synthetically useful chiral primary diarylmethylamines and sterically hindered benzylamines (up to 97 % yield, 93–>99 % ee). Elaborations of the chiral amine products into bioactive compounds and a chiral ligand were demonstrated through manipulation of the removable and convertible -OH group.
- Hu, Le' an,Zhang, Yao,Zhang, Qing-Wen,Yin, Qin,Zhang, Xumu
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supporting information
p. 5321 - 5325
(2020/02/28)
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- Ceric Ammonium Sulfate (CAS) Mediated Oxidations of Benzophenones Possessing a Phenolic Substituent for the Synthesis of Xanthones and Related Products
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Work previously published by our group described novel methodology for the synthesis of xanthones and related products from phenolic benzophenones in a reaction mediated by ceric ammonium sulfate (CAS). In this paper we further explore this novel reaction by subjecting an additional set of phenolic benzophenones to CAS to afford a range of compounds, including xanthones, 9H-xanthen-2,9(4aH)-diones, 3H-spiro[benzofuran-2,1′-cyclohexa[2,5]diene]-3,4′-diones, and biaryl compounds. A comparison of these reactions with the more commonly used oxidant ceric ammonium nitrate (CAN) was also conducted. Based on these results, greater insight into the reaction mechanism has been gained. In addition, the conversion of the synthesized xanthen-2,9(4aH)-diones to xanthones by treatment with sodium dithionite is described.
- Dam, Jean,Bode, Moira L.,De Koning, Charles B.
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p. 150 - 160
(2019/01/10)
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- Integrating Metal-Catalyzed C-H and C-O Functionalization to Achieve Sterically Controlled Regioselectivity in Arene Acylation
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One major goal of organometallic chemists is the direct functionalization of the bonds most recurrent in organic molecules: C-H, C-C, C-O, and C-N. An even grander challenge is C-C bond formation when both precursors are of this category. Parallel to this is the synthetic goal of achieving reaction selectivity that contrasts with conventional methods. Electrophilic aromatic substitution (EAS) via Friedel-Crafts acylation is the most renowned method for the synthesis of aryl ketones, a common structural motif of many pharmaceuticals, agrochemicals, fragrances, dyes, and other commodity chemicals. However, an EAS synthetic strategy is only effective if the desired site for acylation is in accordance with the electronic-controlled regioselectivity of the reaction. Herein we report steric-controlled regioselective arene acylation with salicylate esters via iridium catalysis to access distinctly substituted benzophenones. Experimental and computational data indicate a unique reaction mechanism that integrates C-O activation and C-H activation with a single iridium catalyst without an exogenous oxidant or base. We disclose an extensive exploration of the synthetic scope of both the arene and the ester components, culminating in the concise synthesis of the potent anticancer agent hydroxyphenstatin.
- Serratore, Nicholas A.,Anderson, Constance B.,Frost, Grant B.,Hoang, Truong-Giang,Underwood, Steven J.,Gemmel, Philipp M.,Hardy, Melissa A.,Douglas, Christopher J.
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supporting information
p. 10025 - 10033
(2018/07/21)
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- Rhodium-Catalyzed Directing-Group-Assisted Aldehydic C–H Arylations with Aryl Halides
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A rhodium-catalyzed general protocol for the directing-group-assisted arylation of aromatic aldehydic C–H bonds was developed. This method involves either hydroxy- or amino-group-directed aldehyde C–H arylation with various aryl halides. A broad synthetic scope for the preparation of 2-hydroxybenzophenones was established with electronically variant salicylaldehydes and aryl halides with chemo- and regioselective possibilities. The developed protocol was also applied in the synthesis of medicinally important 3-salicyloylpyridines in high yields.
- Rao, Maddali L. N.,Ramakrishna, Boddu S.
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p. 5080 - 5093
(2017/09/20)
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- Novel one-pot synthesis of xanthones via sequential fluoride ion-promoted fries-type rearrangement and nucleophilic aromatic substitution
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A novel and efficient synthesis of xanthones is described. 2-(Trimethylsilyl)phenyl 2-fluorobenzoate derivatives undergo Fries-type rearrangement and intramolecular SNAr reaction in a one-pot sequential manner under fluoride ion-promoted mild conditions. The method provides efficient access to xanthones that have significant steric congestion around the C9 carbonyl, which are not readily available by conventional methods. Georg Thieme Verlag Stuttgart · New York.
- Fujimoto, Yuuki,Itakura, Ryohei,Hoshi, Hiroki,Yanai, Hikaru,Ando, Yoshio,Suzuki, Keisuke,Matsumoto, Takashi
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p. 2575 - 2580
(2013/12/04)
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- Xanthones in heterocyclic synthesis. An efficient route for the synthesis of C-3 o-Hydroxyaryl substituted 1, 2-benzisoxazoles and their N-oxides, potential scaffolds for angiotensin(II) antagonist hybrid peptides
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Regioselective substitution of xanthone and its nucleophilic cleavage allow the synthesis of C-3 ohydroxyaryl substituted 1, 2-benzisoxazoles or their V-oxides by cyclodehydration or oxidative cyclization of their corresponding ketoxime precursors, respectively. Molecular modeling analysis and 1H NMR spectra indicate an intramolecular H-bonding engaging phenol OH and the isoxazole ring N atom. The Japan Institute of Heterocyclic Chemistry.
- Gardikis, Yiannis,Tsoungas, Petros G.,Potamitis, Constantinos,Zervou, Maria,Cordopatis, Paul
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experimental part
p. 1077 - 1091
(2011/06/19)
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- Xanthones in heterocyclic synthesis. An efficient and general route for the synthesis of regioselectively substituted phthalazines
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Xanthone undergoes regioselective substitution and nucleophically - triggered ring opening to the corresponding ketone. Hydrazone of the latter oxidatively rearranges to ortho-diacylarenes, which, then, with hydrazine gives regioselectively substituted phthalazines. Molecular modeling analysis and 1HNMR spectra indicate an intramolecular H-bonding engaging phenol OH and phthalazine N-3 atom.
- Gardikis, Yiannis,Tsoungas, Petros G.,Potamitis, Constantinos,Pairas, George,Zervou, Maria,Cordopatis, Paul
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scheme or table
p. 1291 - 1302
(2011/06/27)
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- Selective syntheses of partially etherified derivatives of tetrakis(2-hydroxyphenyl)ethene. An alternative to the calix[4]arene ligand system
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Stereoselective syntheses of (E)- and (Z)-1,2-bis(2′-hydroxyphenyl)- bis(2′-methoxyphenyl)ethene have been developed, the former by convergent coupling of an orthogonally protected 2,2′-benzophenone derivative and the latter by selective partial dealkylat
- Fujita, Megumi,Qi, Guizhong,Verkerk, Udo H.,Dzwiniel, Trevor L.,McDonald, Robert,Stryker, Jeffrey M.
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p. 2653 - 2656
(2007/10/03)
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- Substituted tetraarylethylene compounds
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The present invention seeks to provide novel tetraarylethylene compounds which are substituted on the aryl rings ortho to the ethylenic carbon atoms and processes for the preparation for such compounds. The compounds have potential use as molecular templates.
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- Synthesis of 3-ureido derivatives of coumarin and 2-quinolone as potent Acyl-CoA: Cholesterol acyltransferase inhibitors
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Novel 3-ureido derivatives of 4-phenylcoumarin and 4-phenyl-2-quinolone were synthesized and evaluated for acyl-CoA: cholesterol acyltransferase (ACAT)-inhibitory activity. These derivatives inhibited rat intestinal ACAT with IC50 values at the 10-8 to 10-9 M level and were found to normalize plasma cholesterol levels in cholesterol-fed rats when administered as dietary admixtures.
- Tawada,Natsugari,Ishikawa,Sugiyama,Ikeda,Meguro
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p. 616 - 625
(2007/10/02)
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- A Complex Induced Proximity Effect in the Anionic Fries Rearrangement of o-Iodophenyl Benzoates: Synthesis of Dihydro-O-methylsterigmatocystin and Other Xanthones
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The success of an anionic Fries rearrangement, used to synthesise dihydro-O-methylsterigmatocystin and other xanthones, is dependent on the presence of a remote methoxyl substituent.
- Horne, Stephen,Rodrigo, Russell
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p. 4520 - 4522
(2007/10/02)
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- Synthesis of Isocoumestan
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Isocoumestan (II) has been synthesized by condensing 2,2'-dihydroxybenzophenone (I) with diethyl bromomalonate in the presence of K2CO3/methyl ethyl ketone.
- Joshi, U. K.,Kelkar, R. M.,Paradkar, M. V.
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p. 456 - 457
(2007/10/02)
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