37051-70-0Relevant articles and documents
Oxidative Catalytic Spiroketalization Leading to Diastereoselective Synthesis of Spiro[benzofuran-2,1′-isochromene]s
Qiu, Jiang-Kai,Hao, Wen-Juan,Li, Guigen,Jiang, Bo
, p. 1182 - 1192 (2018)
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
Regioselective/electro-oxidative intermolecular [3 + 2] annulation for the preparation of indolines
Wang, Qingqing,Wang, Pan,Gao, Xinlong,Wang, Dan,Wang, Shengchun,Liang, Xingan,Wang, Liwei,Zhang, Heng,Lei, Aiwen
, p. 2181 - 2186 (2020)
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
Highly enantioselective [3+2] coupling of indoles with quinone monoimines promoted by a chiral phosphoric acid
Liao, Lihua,Shu, Chang,Zhang, Minmin,Liao, Yijun,Hu, Xiaoyan,Zhang, Yonghong,Wu, Zhijun,Yuan, Weicheng,Zhang, Xiaomei
, p. 10471 - 10475 (2014)
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.
Hemin-catalyzed biomimetic oxidative phenol-indole [3 + 2] reactions in aqueous media
Fu, Yu,Yu, Qile,Zhang, Yulong,Gao, Zhonghong,Wu, Yuzhou,Zhong, Fangrui
, p. 9994 - 9998 (2019)
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).
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
Chen, Xingyu,Lu, Sixian,Deng, Ping,Chang, Xiaoqiang,Zhao, Yifan,Ma, Yue,Zhang, Dong,Xia, Fei,Yang, Lan,Wang, Jigang,Sun, Peng
, p. 94 - 102 (2021/10/05)
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.).
Synthesis of indole-fused scaffolds via [3+3] cyclization reaction of 2-indolylmethanols with quinone imines
Qin, Lu-Zhe,Cheng, Ya-Long,Wen, Xiaoan,Xu, Qing-Long,Zhen, Le
, (2020/12/07)
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.
Dehydrogenation/(3+2) Cycloaddition of Saturated Aza-Heterocycles via Merging Organic Photoredox and Lewis Acid Catalysis
Xiao, Teng-Fei,Zhang, Yi-Fan,Hou, Wen-Tao,Yan, Pen-Ji,Hai, Jun,Xu, Peng-Fei,Xu, Guo-Qiang
supporting information, p. 8942 - 8946 (2021/11/24)
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.
Enantioselective dearomative [3+2] annulation of 5-amino-isoxazoles with quinone monoimines
Liu, Hui,Yan, Yingkun,Zhang, Jiayan,Liu, Min,Cheng, Shaobing,Wang, Zhouyu,Zhang, Xiaomei
, p. 13591 - 13594 (2020/11/17)
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
Synthesis of Novel Pterocarpen Analogues via [3?+?2] Coupling-Elimination Cascade of α,α-Dicyanoolefins with Quinone Monoimines
Chen, Hui,Zhao, Sihan,Cheng, Shaobing,Dai, Xingjie,Xu, Xiaoying,Yuan, Weicheng,Zhang, Xiaomei
, p. 1672 - 1683 (2019/04/08)
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.
Silver/Scandium-Cocatalyzed Bicyclization of β-Alkynyl Ketones Leading to Benzo[c]xanthenes and Naphtho[1,2-b]benzofurans
Chen, Ke,Liu, Shuai,Wang, Dan,Hao, Wen-Juan,Zhou, Peng,Tu, Shu-Jiang,Jiang, Bo
, p. 11524 - 11530 (2017/11/10)
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.
