- Aerobic Copper-Catalyzed Intramolecular Cascade Oxidative Isomerization/[4+4] Cyclization of 2,2′-Disubstituted Stilbenes
-
An aerobic copper-catalyzed cascade oxidative isomerization/[4+4] cyclization of 2,2′-disubstituted stilbenes is described. Under the mild CuCl/DBED/air catalytic system, various 5,10-heteroatom-containing tetrahydroindeno[2,1-a]indenes were efficiently p
- Zhang, Zhi-Jun,Zhou, Xu,Li, Dashan,Chen, Yang,Xiao, Wen-Wen,Li, Rong-Tao,Shao, Li-Dong
-
p. 7609 - 7624
(2021/05/29)
-
- One-Step Synthesis of Substituted Benzofurans from ortho- Alkenylphenols via Palladium-Catalyzed C=H Functionalization
-
A dehydrogenative oxygenation of C(sp2)=H bonds with intramolecular phenolic hydroxy groups has been developed, which provides a straightforward and concise access to structurally diversely benzofurans from ortho-alkenylphenols. The reaction is catalyzed by palladium on carbon (Pd/C) without any oxidants and sacrificing hydrogen acceptors.
- Yang, Dejun,Zhu, Yifei,Yang, Na,Jiang, Qiangqiang,Liu, Renhua
-
supporting information
p. 1731 - 1735
(2016/06/09)
-
- Palladium-Catalyzed Domino Process: Synthesis of Symmetrical Diarylalkynes, cis- and trans-Alkenes using Lithium Acetylide as a Synthon
-
An efficient domino protocol has been developed for the synthesis of symmetrical diarylalkynes. Notably, the method was successful in the presence of a palladium catalyst without the support of a copper co-catalyst. Significantly, the method enabled the use of the commercially available and cheap lithium acetylide ethylenediamine complex as a source of acetylene for the construction of dual C-C bonds, with a wide range of compatibility towards various substituents of the aryl bromides/iodides. Significantly, this protocol was successfully applied to the synthesis of cis- and trans-alkenes in a highly stereoselective manner in a sequential one-pot process.
- Krishna, Jonnada,Krishna Reddy, Alavala Gopi,Satyanarayana, Gedu
-
p. 3597 - 3610
(2016/01/25)
-
- Synthesis of 2-Arylphenol Derivatives through a One-Pot Suzuki-Miyaura Coupling/Dehydrogenative Aromatization Sequence with Pd/C Catalysis
-
One-pot synthesis of 2-arylphenols starting from 2-iodo-2-cyclohexen-1-one and arylboronic acids through sequential Suzuki-Miyaura coupling/dehydrogenative aromatization with Pd/C catalysis has been developed. A range of arylboronic acids serve as substrates, including those containing electron-donating or electron-withdrawing groups. Additionally, one-pot synthesis of di- or trisubstituted phenols bearing a phenyl group at the ortho position are also generated by using 2-iodo-2-cyclohexen-1-one derivatives as substrate. In the present method, commercially available and easily removable Pd/C was employed as a catalyst without any ligands. The operationally simple procedure and accessible conditions were used to provide modified phenols as the sole product in moderate to high yields.
- Kikushima, Kotaro,Nishina, Yuta
-
supporting information
p. 5864 - 5868
(2015/09/15)
-
- Copper-catalyzed oxidative aromatization of 2-cyclohexen-1-ones to phenols in the presence of catalytic hydrogen bromide under molecular oxygen
-
Catalytic oxidative aromatization has been achieved using 2-cyclohexen-1-ones to obtain phenol derivatives in the presence of a catalytic amount of copper salt and aqueous HBr under molecular oxygen. The amount of HBr was successfully reduced to a catalytic quantity, and the other additive such as a ligand and an oxidant as well as inert conditions were unnecessary. Various mono-, di-, and trisubstituted phenols with substituents at the desired positions could be synthesized under cheap and simple conditions. An oxidative aromatization/bromination sequence was also demonstrated to obtain bromophenols with excess HBr. The Royal Society of Chemistry 2013.
- Kikushima, Kotaro,Nishina, Yuta
-
p. 20150 - 20156
(2013/11/06)
-
- p-Toluenesulfonic acid-promoted selective functionalization of unsymmetrical arylalkynes: a regioselective access to various arylketones and heterocycles
-
Regioselective hydration of a wide range of internal alkynes has been afforded in high to good yields by using PTSA in EtOH. The scope of the reaction of alkynes has been delineated. Arylaliphatic alkynes and diarylalkynes were regioselectively hydrated in good to excellent yields and short reaction times when the reaction was achieved under microwave irradiation. Moreover, diarylalkynes, arylenynes as well as diaryldiynes bearing a methoxy- or a thiomethyl substituent on the ortho position underwent a regioselective 5-endo-dig-cyclization to give a variety of 2-aryl- and 2-styrylbenzofuran or benzothiphene derivatives. We believe that, this new environmentally metal-free procedure combined to microwave irradiation would be in importance in the search of green laboratory-scale synthesis.
- Jacubert, Maud,Provot, Olivier,Peyrat, Jean-Fran?ois,Hamze, Abdallah,Brion, Jean-Daniel,Alami, Mouad
-
experimental part
p. 3775 - 3787
(2010/07/04)
-
- p-Toluenesulfonic acid-mediated cyclization of o-(1-alkynyl)anisoles or thioanisoles: synthesis of 2-arylsubstituted benzofurans and benzothiophenes
-
A variety of 2-arylbenzo[b]furans are readily prepared in good to excellent yields from the cyclization of o-(1-alkynyl)anisole derivatives under mild reaction conditions using an alcoholic media, p-toluenesulfonic acid under microwave irradiation. Starti
- Jacubert, Maud,Hamze, Abdallah,Provot, Olivier,Peyrat, Jean-Fran?ois,Brion, Jean-Daniel,Alami, Mouad
-
experimental part
p. 3588 - 3592
(2009/09/28)
-
- Efficient synthesis of benzofurans utilizing [3,3]-sigmatropic rearrangement triggered by N-trifluoroacetylation of oxime ethers: Short synthesis of natural 2-arylbenzofurans
-
A new synthetic method for the preparation of benzofurans has been developed. The key step of this method is the [3,3]-sigmatropic rearrangement of N-trifluoroacetyl-ene-hydroxylamines, which was triggered by acylation of oxime ethers. TFAA has been proved to be the best reagent to induce [3,3]-sigmatropic rearrangement for the synthesis of cyclic or acyclic dihydrobenzofurans. On the other hand, the TFAT-DMAP system is found to be the most effective for constructing various benzofurans. Synthetic utility of this reaction is demonstrated by the short synthesis of natural benzofurans without protection of the hydroxy group. The synthesis of Stemofuran A was accomplished via condensation of ketones with aryloxyamine and subsequent reaction with TFAT-DMAP in a four-step synthesis with 72% overall yield. Similarly, Eupomatenoid 6 and Coumestan were synthesized through the reaction of oxime ether with TFAT-DMAP. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Takeda, Norihiko,Miyata, Okiko,Naito, Takeaki
-
p. 1491 - 1509
(2008/09/19)
-
- Asymmetric cyclization via oxygen cation radical: Enantioselective synthesis of cis-4b,9b-dihydrobenzofuro[3,2-b]benzofurans
-
Aerobic oxidative cyclization of 2,2′-dihydroxystilbenes via oxygen cation radical to give cis-4b,9b-dihydrobenzofuro[3,2-b]benzofurans was carried out in an enantioselective manner (up to 89% ee) by using (nitrosyl)Ru(salen) 10 as the catalyst under phot
- Masutani, Kouta,Irie, Ryo,Katsuki, Tsutomu
-
-
- Reduction of o-Hydroxybenzaldehydes by Aqueous Titanium Trichloride. A New Route to 2-(Benzofuran-2-yl)phenols
-
Reduction of o-hydroxybenzaldehydes 1a-k by aqueous titanium trichloride is a new simple way to the synthesis of the title compounds 2a-k.The temperature at which the reduction occurs (50 or 80 deg C) is related to the nature and position of the R group i
- Clerici, Angelo,Porta, Ombretta,Arnone, Alberto
-
p. 1240 - 1248
(2007/10/02)
-
- SYNTHESIS OF BENZOFUROBENZOFURAN AND BENZOFUROBENZOFURAN
-
A convenient method was developed for the synthesis of benzofurobenzofuran and benzofurobenzofuran by the structurally directed heterocyclization of hydrosalicyloin to 4b,9b-dihydrobenzofurobenzofuran or 5a,10b-dihydrobenzofurobenzofuran and their subsequent homolytic bromination and dehydrobromination in the presence of a base.The stuctures of the cyclization products are determined by the nature of the dehydrating agent.The possible mechanism of the cyclization of hydrosalicyloin in the presence of acids is disscused.
- Tolmach, E. L.,Kudryavtsev, A. B.,Zheltov, A. Ya.,Stepanov, B. I.
-
p. 1594 - 1601
(2007/10/02)
-