- Oxidative Catalytic Spiroketalization Leading to Diastereoselective Synthesis of Spiro[benzofuran-2,1′-isochromene]s
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A new one-pot, two-step silver-catalyzed spiroketalization of the in-situ generated quinone imine ketals (QIKs) with β-alkynyl ketones has been established, enabling multiple C?O and C?C bond-forming reactions to access densely functionalized spiro[benzof
- Qiu, Jiang-Kai,Hao, Wen-Juan,Li, Guigen,Jiang, Bo
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- Regioselective/electro-oxidative intermolecular [3 + 2] annulation for the preparation of indolines
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Compared with the reported intramolecular electro-oxidative cyclization of alkenyl amines or vinyl anilines for the preparation of pyrrolidines or indolines, the intermolecular version is less studied. Herein, this electrochemical intermolecular oxidative
- Wang, Qingqing,Wang, Pan,Gao, Xinlong,Wang, Dan,Wang, Shengchun,Liang, Xingan,Wang, Liwei,Zhang, Heng,Lei, Aiwen
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- Highly enantioselective [3+2] coupling of indoles with quinone monoimines promoted by a chiral phosphoric acid
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Highly enantioselective [3+2] coupling of 3-substituted indoles with quinone monoimines promoted by a chiral phosphoric acid has been reported. A large variety of benzofuroindolines were prepared in moderate to good yields (up to 98 %) with generally excellent enantioselectivities (up to 99 % ee). Benzofuroindolines: The title reaction has been realized. A wide variety of benzofuroindolines have been prepared with moderate to good yields in moderate to excellent enantioselectivities. Ts=4-toluenesulfonyl.
- Liao, Lihua,Shu, Chang,Zhang, Minmin,Liao, Yijun,Hu, Xiaoyan,Zhang, Yonghong,Wu, Zhijun,Yuan, Weicheng,Zhang, Xiaomei
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- Hemin-catalyzed biomimetic oxidative phenol-indole [3 + 2] reactions in aqueous media
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A hemin/H2O2 catalytic system for oxidative phenol-indole [3 + 2] coupling in aqueous solution has been developed, enabling benign synthesis of valuable benzofuroindolines under sustainable conditions. Mechanistic studies revealed the dual role of iron porphyrin responsible for both phenol oxidation and Lewis acid activation, which differs from the well-explored chemistry of hemin in carbene and nitrene insertion reactions. A preliminary experiment with cytochrome c showed that the turnover of iron porphyrin was amenable for a macromolecular setting with remarkable efficiency (ca. 13 300 TON).
- Fu, Yu,Yu, Qile,Zhang, Yulong,Gao, Zhonghong,Wu, Yuzhou,Zhong, Fangrui
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- Lewis Acid Regulated Divergent Catalytic Reaction between Quinone Imine Ketals (QIKs) and 1,3-Dicarbonyl Compounds: Switchable Access to Multiple Products Including 2-Aryl-1,3-Dicarbonyl Compounds, Indoles, and Benzofurans
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A catalytic Lewis acid regulated reaction between quinone imine ketals (QIKs) and 1,3-dicarbonyl compounds provides a divergent and tunable approach to a variety of skeletons, including a series of 2-aryl-1,3-dicarbonyl compounds, indoles, and benzofurans. The use of lithium chloride and ferrous bromide gives C3- or C2-alkylation products of the QIKs. The combination of ferrous bromide and trifluoromethanesulfonic acid delivers indole derivatives. Sequential hydrolysis and C3-alkylation occur in the presence of ytterbium (III) trifluoromethanesulfonate and stoichiometric amounts of water. When the reaction is performed with trifluoromethanesulfonic acid and stoichiometric amounts of water, benzofuran is obtained. This protocol utilizes mild conditions, exhibits regio- and chemoselectivity, and has broad functional group tolerance. (Figure presented.).
- Chen, Xingyu,Lu, Sixian,Deng, Ping,Chang, Xiaoqiang,Zhao, Yifan,Ma, Yue,Zhang, Dong,Xia, Fei,Yang, Lan,Wang, Jigang,Sun, Peng
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- Synthesis of indole-fused scaffolds via [3+3] cyclization reaction of 2-indolylmethanols with quinone imines
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A formal [3 + 3] cyclization reaction of 2-indolylmethanols with quinones was realized to furnish indole-fused scaffolds in moderate to excellent yields. This protocol was proceeded smoothly under acid condition, with high high yields and broad substrate scope.
- Qin, Lu-Zhe,Cheng, Ya-Long,Wen, Xiaoan,Xu, Qing-Long,Zhen, Le
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- Dehydrogenation/(3+2) Cycloaddition of Saturated Aza-Heterocycles via Merging Organic Photoredox and Lewis Acid Catalysis
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Herein, we report a photoinduced dehydrogenation/(3+2) cycloaddition reaction by merging organic photoredox and Lewis acid catalysis, providing a straightforward and efficient approach for directly installing a benzofuran skeleton on the saturated aza-heterocycles. In this protocol, we also describe a novel organic photocatalyst (t-Bu-DCQ) with the advantages of a wider redox potential, easy synthesis, and a low price. Furthermore, the stepwise activation mechanism of dual C(sp3)-H bonds was demonstrated by a series of experimental and computational studies.
- Xiao, Teng-Fei,Zhang, Yi-Fan,Hou, Wen-Tao,Yan, Pen-Ji,Hai, Jun,Xu, Peng-Fei,Xu, Guo-Qiang
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supporting information
p. 8942 - 8946
(2021/11/24)
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- Enantioselective dearomative [3+2] annulation of 5-amino-isoxazoles with quinone monoimines
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The first enantioselective dearomative [3+2] annulation of 5-amino-isoxazoles with quinone monoimines was realized using a chiral phosphoric acid as catalyst. Various novel (bridged) isoxazoline fused dihydrobenzofurans bearing two continuous quaternary stereocenters were achieved in moderate to good yields (up to 94%) with moderate to good enantioselectivities (up to 98% ee). The absolute configurations of two products were assigned by X-ray crystal structural analyses and a plausible reaction mechanism was proposed. This journal is
- Liu, Hui,Yan, Yingkun,Zhang, Jiayan,Liu, Min,Cheng, Shaobing,Wang, Zhouyu,Zhang, Xiaomei
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p. 13591 - 13594
(2020/11/17)
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- Synthesis of Novel Pterocarpen Analogues via [3?+?2] Coupling-Elimination Cascade of α,α-Dicyanoolefins with Quinone Monoimines
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By employing triethylamine as a catalyst, [3?+?2] coupling-elimination cascade of α,α-dicyanoolefins with quinone monoimines was realized. The reactions afforded various novel pterocarpen analogues with generally moderate yields (up to 75%). In addition, a plausible reaction mechanism was proposed.
- Chen, Hui,Zhao, Sihan,Cheng, Shaobing,Dai, Xingjie,Xu, Xiaoying,Yuan, Weicheng,Zhang, Xiaomei
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p. 1672 - 1683
(2019/04/08)
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- Silver/Scandium-Cocatalyzed Bicyclization of β-Alkynyl Ketones Leading to Benzo[c]xanthenes and Naphtho[1,2-b]benzofurans
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The combination of AgTFA and Sc(OTf)3 enables the bimetallic synergistic catalysis of β-alkynyl ketones and para-quinone methides (p-QMs), allowing direct synthesis of 17 examples of benzo[c]xanthenes with generally good yields through a benzannulation/1,6-addition/cyclization sequence. Exchanging p-QMs for quinone imine ketal resulted in 10 examples of tetracyclic naphtho[1,2-b]benzofurans via a similar benzannulation/1,4-addition/cyclization cascade. During these reaction processes, AgTFA and Sc(OTf)3 could be perfectly compatible, together with the realization of C(sp3)-H functionalization adjacent to carbonyl group on the β-alkynyl ketone unit.
- Chen, Ke,Liu, Shuai,Wang, Dan,Hao, Wen-Juan,Zhou, Peng,Tu, Shu-Jiang,Jiang, Bo
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p. 11524 - 11530
(2017/11/10)
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- The Diels-Alder reactions of para-benzoquinone nitrogen-derivatives: An experimental and theoretical study
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An experimental and theoretical study of the comparative reactivity and selectivity of the Diels-Alder reactions of para-benzoquinones and three nitrogen derivatives have been performed. The mono-oximes derivatives do not react under the tested reaction conditions, whereas the tosylated mono-oximes react slowly. However, the mono N-tosyl imines show excellent reactivity, and superior to the parent parabenzoquinones. DFT calculations support these experimental results.
- Uliana, Marciana P.,Servilha, Bruno M.,Alexopoulos, Olga,De Oliveira, Kleber T.,Tormena, Cláudio F.,Ferreira, Marco A.B.,Brocksom, Timothy J.
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p. 6963 - 6973
(2015/11/09)
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- Reaction of some N-substituted 1,4-benzoquinone imines with sodium arenesulfinates
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N-Arylsulfonyl, N-aroyl, and N-[arylsulfonylimino(phenyl)methyl] derivatives of 1,4-benzoquinone imine reacted with sodium arenesulfinates to give 1,4-, 1,6-, and 6,1-addition products which were formed according to two concurrent paths: direct nucleophil
- Konovalova,Avdeenko,Marchenko
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p. 973 - 985
(2014/10/15)
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- Discovery of 4-amino-2-(thio)phenol derivatives as novel protein kinase and angiogenesis inhibitors for the treatment of cancer: Synthesis and biological evaluation. Part II
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A novel series of 4-amino-2-(thio)phenol derivatives were well synthesized. The preliminary biological test revealed that several compounds displayed high specific protein kinase and angiogenesis inhibitory activities compared with previous work mainly because of the substitution of sulfonamide structure for amide fragment. Among which, compound 5i was identified to inhibit protein kinase B/AKT (IC50 = 1.26 μM) and ABL tyrosine kinase (IC 50 = 1.50 μM) effectively. Meanwhile, compound 5i demonstrated competitive in vitro antiangiogenic activities to Pazopanib in both human umbilical vein endothelial cell (HUVEC) tube formation assay and the rat thoracic aorta rings test.
- Xu, Fuming,Zhang, Lei,Jia, Yuping,Wang, Xuejian,Li, Xiaoguang,Wen, Qingli,Zhang, Yingjie,Xu, Wenfang
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p. 191 - 200
(2013/10/01)
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- Anodic oxidation and organocatalysis: Direct regio- And stereo-selective access to meta-substituted anilines by α-arylation of aldehydes
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(Figure presented) What's the potential? An anodic oxidation/ organocatalytic α-arylation of aldehydes using substituted electron-rich aromatic compounds has been developed. The method gives access to meta-substituted anilines and dihydrobenzofurans in go
- Jensen, Kim L.,Franke, Patrick T.,Nielsen, Lasse T.,Daasbjerg, Kim,Jorgensen, Karl Anker
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supporting information; experimental part
p. 129 - 133
(2010/03/30)
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- Selective C3-C3 oxidative cross-coupling between unactivated anilines and indoles
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A selective C3-C3 oxidative cross-coupling between unactivated anilines and indoles catalyzed by copper bromide together with iodobenzene diacetate as the oxidant is described. This methodology provides a novel approach to biaryl synthesis. Copyright
- Wang, Linfei,Han, Zhaomeng,Fan, Renhua
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body text
p. 3230 - 3234
(2011/02/23)
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- Thiocyanation of N-arylsulfonyl-, N-aroyl-, and N-[(N-arylsulfonyl) benzimidoyl]-1,4-benzoquinone imines
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Reactions of thiocyanate ion with N-aroyl-, N-arylsulfonyl-, and N-(N-arylsulfonylbenzimidoyl)-1,4-benzoquinone imines follow the 1,4-addition pattern, and the adducts undergo intramolecular cyclization to give the corresponding N-substituted 5-amino-1,3-
- Avdeenko,Pirozhenko,Konovalov,Roman'Kov,Palamarchuk,Shishkinc
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experimental part
p. 408 - 416
(2009/09/06)
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- Total synthesis of (±)-decursivine
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The first preparation of the antimalarial natural product decursivine is described. A Diels-Alder/Plieninger indolization protocol allows convenient preparation of the indole 15 which, in turn is a suitable substrate for a boron-enolate aldol reaction with piperonal (16). The resulting adduct 14 is transformed efficiently to the natural product. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Leduc, Andrew B.,Kerr, Michael A.
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p. 237 - 240
(2007/10/03)
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- Total synthesis of (±)-herbindole B and (±)-cis-trikentrin B
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(Chemical Equation Presented) Herbindole B and cis-trikentrin B are naturally occurring indoles having the unusual and synthetically challenging pattern of carbon substitution at the 4-7 and 5-7 positions, respectively, with no substitution at the 1-3 positions. The total syntheses of these polyalkylated indoles have been achieved in 19 and 12 steps, respectively. The synthesis of herbindole B relies on two iterations of a quinine monoimine Diels-Alder reaction, while cis-trikentrin B uses a single cycloaddition of a suitable quinone monoimine. Indolization of the adducts provides suitably substituted benzopyrrole nuclei for elaboration to the natural products.
- Jackson, Stephen K.,Banfield, Scott C.,Kerr, Michael A.
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p. 1215 - 1218
(2007/10/03)
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- Synthesis and cross-coupling reactions of substituted 5-triflyloxyindoles
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N-Arylsulfonyl quinone monoimines undergo smooth cycloadditions in a [4+2] sense to yield the expected cycloadducts. The crude cycloadducts, when subjected to a short series of simple transformations, produce synthetically useful quantities of 5-triflylox
- England, Dylan B.,Kerr, Michael A.
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p. 6519 - 6522
(2007/10/03)
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- BROMINATION OF 4-ARENESULFONAMIDOPHENOLS (OR 1-NAPHTHOLS) AND N-ARYLSULFONYL-1,4-BENZO(NAPHTHO)QUINON-4-IMINES
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2,3,6-Tribromo-N-phenylsulfonyl-1,4-benzoquinon-4-imines are formed on bromination of 4-arenesulfonamidophenols and N-aryl-sulfonyl-1,4-benzoquinon-4-imines but 2-bromo-N-arylsulfonyl-1,4-naphthoquinon-4-imines are formed from 4-arenesulfonamido-1-naphthols and N-arylsulfonyl-1,4-naphthoquinon-4-imines.
- Avdeenko, A. P.,Velichko, N. V.
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p. 1687 - 1692
(2007/10/02)
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