- A Facile Construction of Bisheterocyclic Methane Scaffolds through Palladium-Catalyzed Domino Cyclization
-
A convenient palladium-catalyzed domino cyclization reaction for the construction of bis(benzofuranyl)methane scaffolds bearing an all-carbon quaternary center has been described. In the cascade process, one C(sp2)—O bond, two C(sp2)—C(sp3) bonds as well as two benzofuran rings are formed in a single synthetic sequence. The approach shows wide scope of substrates and good functional-group tolerance. Moreover, this methodology is successfully extended to the synthesis of benzofuranyl methyl chromane derivatives.
- Qi, Hongbo,Han, Kaiming,Chen, Shufeng
-
supporting information
p. 2699 - 2704
(2021/08/03)
-
- Thermal [2 + 2]-cycloaddition between silylalkynes and allenylphenols followed by the nucleophilic addition of water: Metal-free and economical synthesis of arylcyclobutenals
-
Herein, we report an unprecedented thermal [2 + 2]-cycloaddition between silylalkynes and allenylphenols to form an aromatizing cyclobutachromene intermediate, followed by the nucleophilic addition of water to yield functionalized arylcyclobutenals. This reaction is atom- and pot-economical because all the atoms contained in the starting material are retained in the final product, no other reactants are required, and it proceeds in one-pot.
- Ohno, Shohei,Avena, Ramon Francisco,Aoyama, Hiroshi,Fujioka, Hiromichi,Arisawa, Mitsuhiro
-
p. 1220 - 1228
(2020/03/11)
-
- Ni-Catalyzed Cycloisomerization between 3-Phenoxy Acrylic Acid Derivatives and Alkynes via Intramolecular Cleavage and Formation of the C-O Bond to Give 2,3-Disubstituted Benzofurans
-
Reactions based on transition-metal-catalyzed C-O bond cleavage have attracted much attention as a new synthetic method. Until now, several intermolecular reactions via C-O bond cleavage of aryl ethers, alkenyl ethers, esters, and others have been reported. Here we report an unprecedented C-O bond cleavage of 3-phenoxy acrylic acid derivatives, followed by intramolecular C-O bond formation with alkynes. This reaction gave 2,3-disubstituted benzofurans having useful functional groups-silyl substituents and acrylic acid derivatives- A t the 2- A nd 3-positions, respectively. This report also described theoretical (DFT) insights into the mechanism.
- Ohno, Shohei,Qiu, Jiawei,Miyazaki, Ray,Aoyama, Hiroshi,Murai, Kenichi,Hasegawa, Jun-Ya,Arisawa, Mitsuhiro
-
supporting information
p. 8400 - 8403
(2019/10/14)
-
- Indium(III)-Catalyzed Synthesis of Benzo[ b]furans by Intramolecular Hydroalkoxylation of ortho-Alkynylphenols: Scope and Mechanistic Insights
-
Indium(III) halides catalyze the hydroalkoxylation reaction of ortho-alkynylphenols to afford benzo[b]furans in good yields. The reaction proceeds with 5-endo-dig regioselectivity with a variety of phenols functionalized at the arene and alkyne moieties in high yields using InI3 (5 mol %) in DCE. Experimental and computational studies support a mechanism based on the indium(III) π-Lewis acid activation of the alkyne followed by nucleophilic addition of the phenol and final protodemetalation to afford the corresponding benzo[b]furan. DFT calculations suggest that dimer In2I6 is the catalytic species through a novel double coordination with the alkyne and the hydroxyl group.
- Alonso-Mara?ón, Lorena,Martínez, M. Montserrat,Sarandeses, Luis A.,Gómez-Bengoa, Enrique,Pérez Sestelo, José
-
p. 7970 - 7980
(2018/06/22)
-
- Gold-Catalyzed Fluorination–Hydration: Synthesis of α-Fluorobenzofuranones from 2-Alkynylphenol Derivatives
-
The AuI-catalyzed fluorination–hydration of 2-alkynylphenol derivatives in the presence of Selectfluor [1-chloromethyl-4-fluoro-1,4-diazoniabicyclo-[2.2.2]octane bis(tetrafluoroborate)] has been developed. This method provides straightforward a
- Wang, Qiang,Jiang, Yu,Sun, Run,Tang, Xiang-Ying,Shi, Min
-
supporting information
p. 14739 - 14745
(2016/10/03)
-
- Rhodium(III)-Catalyzed Cascade Cyclization/Electrophilic Amidation for the Synthesis of 3-Amidoindoles and 3-Amidofurans
-
A rhodium(III)-catalyzed cascade cyclization/electrophilic amidation using N-pivaloyloxylamides as the electrophilic nitrogen source has been developed. This protocol provides an efficient route for the synthesis of 3-amidoindoles and 3-amidofurans under mild conditions with good functional group tolerance. The synthetic utility of this reaction has been demonstrated through the derivatization of the 3-amidoindoles to several heterocycle-fused indoles.
- Hu, Zhiyong,Tong, Xiaofeng,Liu, Guixia
-
supporting information
p. 2058 - 2061
(2016/06/01)
-
- A Palladium-Catalyzed Domino Approach to 2,3-Disubstituted Benzofurans via an Intermolecular Carbopalladation/C(sp3)?H Functionalization/Isomerization Sequence
-
A palladium-catalyzed domino strategy has been developed for the synthesis of 2,3-disubstituted benzofuran derivatives. This cascade reaction sequence involves intermolecular carbopalladation and C(sp3)?H functionalization followed by isomerization. (Figure presented.).
- Boominathan, Siva Senthil Kumar,Hou, Ruei-Jhih,Hu, Wan-Ping,Huang, Po-Jui,Wang, Jeh-Jeng
-
supporting information
p. 2984 - 2989
(2016/09/16)
-
- Highly efficient heterogeneous synthesis of benzofurans under aqueous condition
-
Highly efficient organic reactions in water are important for designing environmental-friendly and low cost synthetic processes. Herein, we demonstrate an intermediate-in-water strategy for the heterogeneous synthesis of benzofurans in aqueous media. The cyclization reaction of 2-(phenylethynyl)phenol to 2-phenylbenzofuran cannot proceed in pure water. However, this reaction can be efficiently promoted by the formation of sparingly soluble intermediate in the presence of alkaline. Quantitative conversion of a variety of substrates to benzofuran derivatives has been achieved in the absence of noble metal catalyst. Other remarkable features including easy-isolation and purification of product, along with wide range of functional group tolerance render the methodology promising in the realm of green-synthesis.
- Sun, Shi-Xin,Wang, Jun-Jie,Xu, Zi-Jun,Cao, Lu-Ya,Shi, Zi-Fa,Zhang, Hao-Li
-
supporting information
p. 3798 - 3806
(2014/05/20)
-
- Tandem gold-catalyzed hydrosilyloxylation-aldol and -Mannich reaction with alkynylaryloxysilanols in 6-exo mode
-
The tandem gold-catalyzed hydrosilyloxylation-aldol and hydrosilyloxylation-Mannich reactions were developed through the formation of an enol silyl ether catalytically generated in situ from alkynylaryloxysilanols in the 6-exo mode in one reaction vessel. Copyright
- Lee, Euichul,Ryu, Taekyu,Park, Youngchul,Park, Sangjune,Lee, Phil Ho
-
p. 1585 - 1596
(2013/06/27)
-
- Potassium tert-butoxide promoted annulation of 2-alkynylphenyl propargyl ethers: Selective synthesis of benzofuran and 12H-benzoannulene derivatives
-
We present here our results on potassium tert-butoxide promoted annulation reactions of 2-alkynylphenyl propargyl ethers to give two different types of heterocycles: 3-benzyl-2-alkynylbenzofurans and 12H-benzoannulenbenzo[b]furans. A series of functionalized 2-alkynylphenyl propargyl ethers were efficiently cyclized by potassium tert-butoxide to the corresponding products. The optimized reaction conditions tolerated a large variety of functional groups, including electron-rich, electron-poor, and N-heterocyclic substrates. Selective product formation was obtained by controlling the solvent and temperature. When THF was used at room temperature, 3-benzyl-2-alkynylbenzofuran derivatives were exclusively obtained, while the use of DMF at 60 C gave selectively 12H-benzoannulen[b]benzofurans.
- Grimaldi, Tamiris B.,Back, Davi F.,Zeni, Gilson
-
p. 11017 - 11031
(2013/11/19)
-
- Gold-catalyzed cyclizations of (o-alkynyl)phenoxyacrylates with external nucleophiles: Regio-and stereoselective synthesis of functionalized benzo[b]oxepines
-
A catalytic approach to benzo[b]oxepines with high stereoselectivity by Au-catalyzed cyclization of (o-alkynyl)phenoxyacrylates with various nucleophiles under mild reaction conditions has been developed. Notably, the use of vinyl ether instead of alcohol could afford the same benzoxepines. The reaction may proceed by Au-catalyzed oligomerization of vinyl ether to release the alcohol, which then reacts with (o-alkynyl)phenoxyacrylates to furnish the benzoxepines.
- Liu, Jun,Liu, Yuanhong
-
supporting information
p. 4742 - 4745,4
(2020/09/16)
-
- Rhodium-catalyzed olefin isomerization/enantioselective intramolecular alder-ene reaction cascade
-
The olefin isomerization/enantioselective intramolecular Alder-ene reaction cascade was achieved by using a cationic rhodium(I)/(R)-BINAP complex as a catalyst. A variety of substituted dihydrobenzofurans and dihydronaphthofurans were obtained from phenol
- Okamoto, Ryuichi,Okazaki, Eri,Noguchi, Keiichi,Tanaka, Ken
-
supporting information; experimental part
p. 4894 - 4897
(2011/11/29)
-
- Cationic palladium(II)-catalyzed synthesis of 2-substituted 3-hydroxymethylbenzo[b]furans
-
A tandem reaction involving an intramolecular oxypalladation of an alkyne and an addition to the carbonyl group to quench the carbon-palladium bond to complete the catalytic cycle was developed. The reaction was catalyzed with the cationic palladium(II) species without the necessity of a redox system. Georg Thieme Verlag Stuttgart · New York.
- Wang, Huan,Han, Xiuling,Lu, Xiyan
-
supporting information; experimental part
p. 2590 - 2594
(2011/11/29)
-
- Synthesis of novel oxygen heterocycles: 1,10-dioxa-cyclopenta[a]fluorene and benzo[b]naphtho[2, 1-d]furans via D?tz intramolecular benzannulation
-
Novel fused heterocycles 1,10-dioxa-cyclopenta[a]fluorene and benzo[b]naphtho[2, 1-d]furans were synthesized via D?tz intramolecular benzannulation of alkyne tethered aryloxy chromium Fischer carbenes.
- Sen, Subhabrata,Kulkarni, Parag,Borate, Kailaskumar,Pai, Nandini R.
-
scheme or table
p. 4128 - 4131
(2009/12/01)
-
- Rhodium-catalysed cyclic carbonylation of 2-alkynylphenols: Synthesis of benzofuranones and coumarins
-
Rhodium-catalysed carbonylation of 2-alkynylphenols 1 under water-gas shift reaction conditions gives benzofuranone derivatives 2 and coumarin derivatives 3 in high yield (up to 96%, 2:3 = 65:35), in which the hydroxy group adjacent to the carbon-carbon triple bond participitates in the cyclic carbonylation.
- Yoneda, Eiji,Sugioka, Takashi,Hirao, Kojiro,Zhahg, Shi-Wei,Takahashi, Shigetoshi
-
p. 477 - 483
(2007/10/03)
-
- Condensed heteroaromatic ring systems. XXIV. Palladium-catalyzed cyclization of 2-substituted phenylacetylenes in the presence of carbon monoxide
-
The palladium-catalyzed reaction of 2-alkynylanilines and 2-alkynylphenols in the presence of carbon monoxide and methanol under basic conditions gave the sequential cyclization/carbonylation products, methyl 2-substituted indole and benzo[b]furan-3-carbo
- Kondo, Yoshinori,Shiga, Futoshi,Murata, Naoko,Sakamoto, Takao,Yamanaka, Hiroshi
-
p. 11803 - 11812
(2007/10/02)
-