- Nickel-Catalyzed Intramolecular Nucleophilic Addition of Aryl Halides to Aryl Ketones for the Synthesis of Benzofuran Derivatives
-
A nickel-catalyzed intramolecular nucleophilic addition reaction of aryl halides to aryl ketones for the formation of benzofuran derivatives has been developed. A number of substrates bearing electron-donating or electron-withdrawing groups were subjected to the standard reaction conditions, giving the corresponding products in moderate to good yields.
- Zhu, Xiao-Rui,Deng, Chen-Liang
-
p. 1842 - 1848
(2021/02/09)
-
- Synthesis of benzofurans from the cyclodehydration of α-phenoxy ketones mediated by Eaton’s reagent
-
Cyclodehydration of α-phenoxy ketones promoted by Eaton’s reagent (phosphorus pentoxide–methanesulfonic acid) is used to prepare 3-substituted or 2,3-disubstituted benzofurans with moderate to excellent yields under mild conditions. The method provides a facile access to benzofurans from readily available starting materials such as phenols and α-bromo ketones. The reaction is highly efficient, which is attributed to the good reactivity and fluidity of Eaton’s reagent. The reaction can be applied to prepare naphthofurans, furanocoumarins, benzothiophenes, and benzopyrans.
- Ma, Zhanwei,Zhou, Min,Ma, Lin,Zhang, Min
-
p. 426 - 436
(2020/03/23)
-
- Mechanistic Insights into Rhenium-Catalyzed Regioselective C-Alkenylation of Phenols with Internal Alkynes
-
A (μ-aryloxo)rhenium complex was isolated and confirmed as a key precatalyst for rhenium-catalyzed ortho-alkenylation (C-alkenylation) of unprotected phenols with alkynes. The reaction exclusively provided ortho-alkenylphenols; the formation of para or multiply alkenylated phenols and hydrophenoxylation (O-alkenylation) products was not observed. Several mechanistic experiments excluded a classical Friedel–Crafts-type mechanism, leading to the proposed phenolic hydroxyl group assisted electrophilic alkenylation as the most plausible reaction mechanism. For this purpose, the use of rhenium, a metal between the early and late transition metals in the periodic table, was key for the activation of both the soft carbon–carbon triple bond of the alkyne and the hard oxygen atom of the phenol, at the same time. ortho-Selective alkenylation with allenes also provided the corresponding adducts with a substitution pattern different from that obtained by the addition reaction with alkynes.
- Murai, Masahito,Yamamoto, Masaki,Takai, Kazuhiko
-
supporting information
p. 15189 - 15197
(2019/11/16)
-
- Dehydrative condensation of carbonyls with non-acidic methylenes enabled by light: Synthesis of benzofurans
-
Condensation of carbonyls with non-acidic methylenes such as those adjacent to heteroatoms and allylic types to generate CC bonds is challenging but highly desirable. Inventing novel methods that can accomplish such condensations can enrich synthetic chemists' toolbox. Herein, we report a simple, clean, and high yielding protocol promoted by light to achieve condensation of non-acidic methylenes with carbonyls. As examples to demonstrate the power of this methodology, one class of ubiquitous and highly important heterocycles, i.e. benzofurans, were synthesized with broad functional group compatibility. Furthermore, intermolecular condensations were also briefly investigated.
- Liu, Wenbo,Chen, Ning,Yang, Xiaobo,Li, Lu,Li, Chao-Jun
-
supporting information
p. 13120 - 13123
(2016/11/09)
-
- The Pd-catalyzed synthesis of benzofused carbo- and heterocycles through carbene migratory insertion/carbopalladation cascades with tosylhydrazones
-
The Pd-catalyzed reaction between o-iodoallylbenzene and tosylhydrazones gives rise to indene derivatives through a process that involves a carbene migratory insertion followed by an intramolecular carbopalladation, with the formation of two C-C bonds on
- Paraja, Miguel,Carmen Pérez-Aguilar,Valdés, Carlos
-
p. 16241 - 16243
(2015/11/10)
-
- Nickel-NHC-catalyzed cross-coupling of 2-methylsulfanylbenzofurans with alkyl grignard reagents
-
NiCl2(PPh3)(IPr) catalyzes cross-coupling reactions of 2-methylsulfanylbenzofurans with alkyl Grignard reagents. Other nickel complexes such as NiCl2(dppe) failed to catalyze the same reaction. The alkylation is applicable to the synthesis of a couple of protein tyrosine phosphatase inhibitors, 3-(4-biphenylyl)-2-alkylbenzofurans.
- Baralle, Alexandre,Otsuka, Shinya,Guérin, Vincent,Murakami, Kei,Yorimitsu, Hideki,Osuka, Atsuhiro
-
supporting information
(2015/02/19)
-
- Facile synthesis of benzofurans via copper-catalyzed aerobic oxidative cyclization of phenols and alkynes
-
Regioselective synthesis of polysubstituted benzofurans using a copper catalyst and molecular oxygen from phenols and alkynes in a one-pot procedure has been reported. The transformation consists of a sequential nucleophilic addition of phenols to alkynes and oxidative cyclization. A wide variety of phenols and alkynes can be used in the same manner.
- Zeng, Wei,Wu, Wanqing,Jiang, Huanfeng,Huang, Liangbin,Sun, Yadong,Chen, Zhengwang,Li, Xianwei
-
supporting information
p. 6611 - 6613
(2013/07/26)
-
- Indium triflate-catalyzed coupling between nitroalkenes and phenol/naphthols: A simple and direct synthesis of arenofurans by a cyclization reaction
-
An eye furan eye: A simple and efficient protocol for the synthesis of benzofuran and naphthofuran derivatives catalyzed by indium triflate was developed by coupling α,β-unsaturated nitroalkenes with phenol/naphthols. The present method provides arenofuran derivatives in one pot from readily available starting materials (DCE=1,2-dichloroethane; see scheme). Copyright
- Kundu, Dhiman,Samim, Md,Majee, Adinath,Hajra, Alakananda
-
supporting information; experimental part
p. 406 - 409
(2011/10/12)
-
- A simple approach to highly functionalized benzo[b]furans from phenols and aryl iodides via aryl propargyl ethers
-
A variety of mono- and disubstituted phenols are alkylated with propargyl bromide to give phenyl 2-propynyl ethers, which were further coupled with aryl iodides under Sonogashira reaction conditions to give 3-phenoxy-1-aryl-1-propyne derivatives. The latt
- Lingam, V.S. Prasada Rao,Vinodkumar, Ramanatham,Mukkanti, Khagga,Thomas, Abraham,Gopalan, Balasubramanian
-
p. 4260 - 4264
(2008/09/21)
-
- Zn(OTf)2-catalyzed cyclization of proparyl alcohols with anilines, phenols, and amides for synthesis of indoles, benzofurans, and oxazoles through different annulation mechanisms
-
Zn(OTf)2 (10 mol %) catalyzed the cyclization of propargyl alcohols with PhXH (X = O, NH) in hot toluene (100 °C) without additive and gave indole and benzofuran products with different structures. In such transformations, α-carbonyl intermedia
- Kumar, Manyam Praveen,Liu, Rai-Shung
-
p. 4951 - 4955
(2007/10/03)
-
- Halogen-metal exchange/cyclization of iodoketones: A direct synthesis of 3-arylbenzofurans
-
The first synthesis of benzofuran 2 was achieved in 17% overall yield in seven steps. The key step was a halogen-metal exchange/cyclization reaction. Several examples of this reaction were reported. Georg Thieme Verlag Stuttgart.
- Kraus, George A.,Schroeder, Jacob D.
-
p. 2504 - 2506
(2007/10/03)
-
- Three-step synthesis of an array of substituted benzofurans using polymer-supported reagents
-
An efficient combinatorial route to substituted 3-phenyl-benzofurans, is achieved by the bromination of acetophenones to α-bromoacetophenones by polymer-supported pyridinium bromide perbromide (PSPBP). The subsequent clean substitution of the obtained bromides by phenols using 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD-P) and cyclodehydration of the resulting α-phenoxyacetophenones using Amberlyst 15, affords pure products without the need for any chromatographic purification step.
- Habermann, Joerg,Ley, Steven V.,Smits, Rene
-
p. 2421 - 2423
(2007/10/03)
-
- Titanium-Induced Syntheses of Furans, Benzofurans and Indoles
-
Highly reactive titanium on graphite as the reagent of choice promotes intramolecular McMurry type reactions of acyloxy- and acylamido carbonyl compounds affording furans, benzofurans and indoles in good to excellent yields.A variety of reducible groups in the substrates is tolerated (e.g. -F, -Cl, -Br, -I, -CF3, -OMe, -CN, -thiophenyl, -COOR, -CONR2) and strained products such as 11h can be obtained, the X-ray analysis of which is reported.The experimental results indicate the possible formation of dianions from the aromatic aldehydes or ketones as reactive intermediates which attack the ester or amide functions in their proximity, rather than a radical path via ketyls.
- Fuerstner, Alois,Jumbam, Denis N.
-
p. 5991 - 6010
(2007/10/02)
-
- Titanium-induced syntheses of furans and indoles
-
Aromatic acyloxycarbonyl- and acylamidocarbonyl compounds on treatment with titanium on graphite (4 equivalents) readily afford (benzo)furans and indoles respectively, by an unprecedented McMurry-type reaction.
- Furstner,Jumbam,Weidmann
-
p. 6695 - 6696
(2007/10/02)
-