- Palladium-Catalyzed Tandem Synthesis of 2-Trifluoromethylthio(seleno)-Substituted Benzofused Heterocycles
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The tandem synthesis of 2-trifluoromethylthio(seleno)-substituted benzofurans using palladium-catalyzed conditions is reported. Trifluoromethylthio(seleno)lation of 2-(2,2-dibromovinyl)phenols with (bpy)CuSCF3 or [(bpy)CuSeCF3]2
- Zhang, Mengjia,Weng, Zhiqiang
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- Palladium-Catalyzed Domino Cyclization/Phosphorylation of gem-Dibromoolefins with P(O)H Compounds: Synthesis of Phosphorylated Heteroaromatics
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We presented a palladium-catalyzed domino cyclization/phosphorylation of gem-dibromoolefins, which utilize H-phosphinates and secondary phosphine oxides as the phosphine sources, respectively. A variety of phosphorylated heteroaromatics were obtained in m
- Chen, Chen,Ding, Jie,Liu, Liying,Huang, Yujie,Zhu, Bolin
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p. 200 - 205
(2021/10/29)
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- Highly Efficient Synthesis of 2-Substituted Benzo[ b ]furan Derivatives from the Cross-Coupling Reactions of 2-Halobenzo[ b ]furans with Organoalane Reagents
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A highly efficient and simple route for the synthesis of 2-substituted benzo[ b ]furans has been developed by palladium-catalyzed cross-coupling reaction of 2-halobenzo[ b ]furans with aryl, alkynyl, and alkylaluminum reagents. Various 2-aryl-, 2-alkynyl-, and 2-alkyl-substituted benzo[ b ]furan derivatives can be obtained in 23-97% isolated yields using 2-3 mol% PdCl 2/4-6 mol% XantPhos as the catalyst under mild reaction conditions. The aryls bearing electron-donating or electron-withdrawing groups in 2-halobenzo[ b ]furans gave products in 40-97% isolated yields. In addition, aluminum reagents containing thienyl, furanyl, trimethylsilanyl, and benzyl groups worked efficiently with 2-halobenzo[ b ]furans as well, and three bioactive molecules with 2-substituted benzo[ b ]furan skeleton were synthesized. Furthermore, the broad substrates scope and the typical maintenance of vigorous efficiency on gram scale make this protocol a potentially practical method to synthesize 2-substituted benzo[ b ]furan derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed.
- Wen, Chang,Wu, Chuan,Luo, Ruiqiang,Li, Qinghan,Chen, Feng
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p. 3847 - 3861
(2021/07/02)
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- Direct bromodeboronation of arylboronic acids with CuBr2 in water
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An efficient and practical method has been developed for the preparation of aryl bromides via the direct bromodeboronation of arylboronic acids with CuBr2 in water. This strategy provides several advantages, such as being ligand-free, base-free, high yielding, and functional group tolerant.
- Tang, Yan-Ling,Xia, Xian-Song,Gao, Jin-Chun,Li, Min-Xin,Mao, Ze-Wei
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supporting information
(2021/01/05)
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- Tandem Synthesis of 2-Carboxybenzofurans via Sequential Cu-Catalyzed C-O Coupling and Mo(CO)6-Mediated Carbonylation Reactions
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A modular tandem synthesis of 2-carboxybenzofurans from 2-gem-dibromovinylphenols has been established based on a sequence of Cu-catalyzed intramolecular C-O coupling and Mo(CO)6-mediated intermolecular carbonylation reactions. This protocol allowed one-step access to a broad variety of functionalized benzofuran-2-carboxylic acids, esters, and amides in good to excellent yields under Pd- and CO gas-free conditions.
- Mo, Qinliang,Sun, Nan,Jin, Liqun,Hu, Baoxiang,Shen, Zhenlu,Hu, Xinquan
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p. 11490 - 11500
(2020/10/12)
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- Transition-metal-free decarboxylative bromination of aromatic carboxylic acids
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Methods for the conversion of aliphatic acids to alkyl halides have progressed significantly over the past century, however, the analogous decarboxylative bromination of aromatic acids has remained a longstanding challenge. The development of efficient methods for the synthesis of aryl bromides is of great importance as they are versatile reagents in synthesis and are present in many functional molecules. Herein we report a transition metal-free decarboxylative bromination of aromatic acids. The reaction is applicable to many electron-rich aromatic and heteroaromatic acids which have previously proved poor substrates for Hunsdiecker-type reactions. In addition, our preliminary mechanistic study suggests that radical intermediates are not involved in this reaction, which is in contrast to classical Hunsdiecker-type reactivity. Overall, the process demonstrates a useful method for producing valuable reagents from inexpensive and abundant starting materials.
- Quibell, Jacob M.,Perry, Gregory J. P.,Cannas, Diego M.,Larrosa, Igor
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p. 3860 - 3865
(2018/04/26)
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- Asymmetric hydrogenation of furans and benzofurans with iridium-pyridine-phosphinite catalysts
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Enantioselective hydrogenation of furans and benzofurans remains a challenging task. We report the hydrogenation of 2- and 3-substituted furans by using iridium catalysts that bear bicyclic pyridine-phosphinite ligands. Excellent enantioselectivities and high conversions were obtained for monosubstituted furans with a 3-alkyl or 3-aryl group. Furans substituted at the 2-position and 2,4-disubstituted furans proved to be more difficult substrates. The best results (80-97% conversion, 65-82% enantiomeric excess) were obtained with monosubstituted 2-alkylfurans and 2-[4-(trifluoromethyl)phenyl]furan. Benzofurans with an alkyl substituent at the 2- or 3-position also gave high conversions and enantioselectivity, whereas 2-aryl derivatives showed essentially no reactivity. The asymmetric hydrogenation of a 3-methylbenzofuran derivative was used as a key step in the formal total synthesis of the cytotoxic naphthoquinone natural product (-)-thespesone.
- Pauli, Larissa,Tannert, Re,Scheil, Robin,Pfaltz, Andreas
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p. 1482 - 1487
(2015/01/30)
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- Modulators of methyl modifying enzymes, compositions and uses thereof
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Agents for modulating methyl modifying enzymes, compositions and uses thereof are provided herein.
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- Pd-catalyzed tandem chemoselective synthesis of 2-arylbenzofurans using threefold arylating triarylbismuth reagents
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A tandem chemoselective synthesis of 2-arylbenzofurans was accomplished from o-hydroxy-gem-(dibromovinyl)benzenes and BiAr3 reagents under palladium-catalyzed conditions. This unique and synthetically valuable strategy proceeds through three consecutive coupling reactions involving triarylbismuth reagents and provides 2-arylbenzofuran products in high yields. A tandem chemoselective synthesis of 2-arylbenzofurans was accomplished from o-hydroxy-gem-(dibromovinyl)benzenes and BiAr3 reagents under palladium-catalyzed conditions. This unique and synthetically valuable strategy proceeds through three consecutive coupling reactions involving triarylbismuth reagents and provides 2-arylbenzofuran products in high yields. Copyright
- Rao, Maddali L. N.,Jadhav, Deepak N.,Dasgupta, Priyabrata
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p. 781 - 788
(2013/03/13)
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- MODULATORS OF METHYL MODIFYING ENZYMES, COMPOSITIONS AND USES THEREOF
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Agents for modulating methyl modifying enzymes, compositions and uses thereof are provided herein
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- Trace amount Cu (ppm)-catalyzed intramolecular cyclization of 2-(gem-dibromovinyl)phenols(thiophenols) to 2-bromobenzofurans(thiophenes)
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An intramolecular cyclization of 2-(gem-dibromovinyl)phenols(thiophenols) to give 2-bromobenzofurans(thiophenes) in the presence of a trace amount of Cu (0.0064 mol%, 25 ppm) has been developed. The reaction provides the desired products in excellent yields under fluoride-free and mild reaction conditions and with a TON (turnover number) of up to 1.5 × 104. The Royal Society of Chemistry 2013.
- Ji, Yong,Li, Pinhua,Zhang, Xiuli,Wang, Lei
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supporting information
p. 4095 - 4101
(2013/07/05)
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- An efficient tandem elimination-cyclization-desulfitative arylation of 2-(gem-dibromovinyl)phenols(thiophenols) with sodium arylsulfinates
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An efficient tandem elimination-cyclization-desulfitative arylation of 2-(gem-dibromovinyl)phenols(thiophenols) with sodium arylsulfinates has been developed. In the presence of TBAF-PdCl2-Cu(OAc)2-NEt 3, the reactions gen
- Chen, Wei,Li, Pinhua,Miao, Tao,Meng, Ling-Guo,Wang, Lei
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supporting information
p. 420 - 424
(2013/02/23)
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- Halodeboronation of organotrifluoroborates using tetrabutylammonium tribromide or cesium triiodide
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Halodeboronation of organotrifluoroborates using commercially available tetrabutylammonium tribromide (TBATB) or cesium triiodide in aqueous medium is reported. The mild, transition metal-free method has proven to be tolerant of a wide range of functional groups. High regio- and chemoselectivity are observed. Two synthetic routes to (Z)-dibromoalkenes from alkynes, through stereodefined (Z)-2-bromoalkenyltrifluoroborates and (Z)-1,2-bis(boryl) alkenyltrifluoroborates, have been developed using the TBATB mediated bromodeboronation as the key step.
- Yao, Min-Liang,Kabalka, George W.,Blevins, David W.,Reddy, Marepally Srinivasa,Yong, Li
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experimental part
p. 3738 - 3743
(2012/06/30)
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- A highly efficient tandem reaction of 2-(gem-dibromovinyl) phenols(thiophenols) with organosilanes to 2-arylbenzofurans (thiophenes)
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2-Arylbenzofurans(thiophenes) were prepared through an efficient tandem elimination-intramolecular addition-Hiyama cross-coupling reaction. In the presence of tetra-(n-butyl)ammonium fluoride (TBAF), palladium(II) acetate [Pd(OAc)2] and triphenylphosphine (PPh3), the reaction of 2-(gem-dibromovinyl)phenols(thiophenols) with phenyl(trialkoxy)silanes proceeded smoothly and generated the corresponding products with good yields in one-pot. It should be noted that TBAF plays an important role in the tandem reaction. Copyright
- Liu, Jie,Chen, Wei,Ji, Yong,Wang, Lei
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supporting information; experimental part
p. 1585 - 1592
(2012/07/14)
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- A highly efficient one-pot reaction of 2-(gem-dibromovinyl) phenols(thiophenols) with K4Fe(CN)6 to 2-cyanobenzofurans(thiophenes)
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2-Cyanobenzofurans and 2-cyanobenzothiophenes were prepared through an efficient one-pot Ullmann-reaction/cyanation reaction. In the presence of CuI/Na2CO3-Pd(OAc)2/PPh3 in DMF, the reaction of 2-(gem-dibromovinyl)phenols and 2-(gem-dibromovinyl)thiophenols with K4Fe(CN)6, as non-toxic and user-friendly cyanating reagent, proceeded smoothly to generate the corresponding 2-cyanobenzofurans and 2-cyanobenzothiophenes in good yields.
- Zhou, Wei,Chen, Wei,Wang, Lei
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supporting information; experimental part
p. 4172 - 4178
(2012/07/03)
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- Highly efficient copper/palladium-catalyzed tandem Ullman reaction/arylation of azoles via C-H activation: Synthesis of benzofuranyl and indolyl azoles from 2-(gem-dibromovinyl)phenols(anilines) with azoles
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In this paper, a novel and highly efficient copper/palladium-catalyzed tandem intramolecular Ullman-type C-O(N) coupling reaction of 2-(gem-dibromovinyl)phenols(anilines) followed by an intermolecular arylation of azoles through C-H activation has been developed. In the presence of CuBr with Pd(PPh3)2Cl2 used as co-catalyst, and LiO tBu as a base, the one-pot reactions of 2-(gem-dibromovinyl)phenols and 2-(gem-dibromovinyl)anilines with a variety of azoles, including oxazoles, imidazoles, thiazoles, and oxadiazoles underwent smoothly in toluene at 100 °C to generate the corresponding biheteroaryl products in high yields. A tentative mechanism of copper/palladium-catalyzed tandem reaction was described.
- Chen, Wei,Wang, Min,Li, Pinhua,Wang, Lei
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scheme or table
p. 5913 - 5919
(2011/09/19)
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- A highly efficient TBAF-promoted intramolecular cyclization of gem-dibromoolefins for the synthesis of 2-bromobenzofurans(thiophenes)
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A highly efficient tetra-(n-butyl)ammonium fluoride (TBAF)-promoted intramolecular cyclization of gem-dibromoolefins has been developed for the synthesis of 2-bromobenzofused heterocycles. The reaction provides a convenient approach to 2-bromobenzofurans(
- Chen, Wei,Zhang, Yicheng,Zhang, Lei,Wang, Min,Wang, Lei
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supporting information; experimental part
p. 10476 - 10478
(2011/10/31)
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- Chemoselective bromodeboronation of organotrifluoroborates using tetrabutylammonium tribromide: Application in (Z)-dibromoalkene syntheses
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(Chemical Equation Presented) Tetrabutylammonlum trlbromlde (TBATB) has been found to be a unique bromodeboronatlon reagent for organotrlf luoroborates. When compared to previously reported bromodeboronatlon methods, the mild and metal-free reaction conditions tolerate a wider range of functional groups. High reglo- and chemoselectlvlty are observed In the presence of both unsaturated carbon-carbon bonds and aldehyde functional groups. An efficient synthetic route to (Z)-dlbromoalkenes from terminal alkynes has been developed using the TBATB-medlated bromodeboronatlon as a key step.
- Yao, Min-Liang,Reddy, Marepally Srinivasa,Li, Yong,Walfish, Ingrid,Blevins, David W.,Kabalka, George W.
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supporting information; experimental part
p. 700 - 703
(2010/04/02)
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- Intramolecular cross-coupling of gem-dibromoolefins: A mild approach to 2-bromo benzofused heterocycles
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Highly useful halogenated benzofurans and benzothiophenes are prepared from readily available gem-dibromoolefins using a mild, ligand-free copper catalyzed cross-coupling procedure.
- Newman, Stephen G.,Aureggi, Valentina,Bryan, Christopher S.,Lautens, Mark
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supporting information; experimental part
p. 5236 - 5238
(2010/01/31)
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