40485-03-8Relevant academic research and scientific papers
Palladium complexes with an annellated mesoionic carbene (MIC) ligand: Catalytic sequential Sonogashira coupling/cyclization reaction for one-pot synthesis of benzofuran, indole, isocoumarin and isoquinolone derivatives
Bera, Jitendra K.,Daw, Prosenjit,Reshi, Noor U Din,Tyagi, Akshi
supporting information, p. 15238 - 15248 (2020/11/18)
Two Pd(ii) complexes (1 and 2) featuring a fused π-conjugated imidazo[1,2-a][1,8]naphthyridine-based mesoionic carbene ligand have been synthesized and structurally characterized. Both complexes effectively catalyze the one-pot synthesis of benzofuran starting from phenylacetylene and 2-iodophenol under mild conditions. Complex 1 is found to be an excellent catalyst for the straightforward access to a library of benzofuran, indole, isocoumarin and isoquinolone derivatives by the reaction of terminal alkynes with 2-iodo derivates of phenol, N-methyl aniline, benzoic acid and N-methyl benzamide, respectively. The general utility of the catalytic method is demonstrated using a variety of diversely substituted terminal alkynes and the corresponding desired products are obtained in good to excellent yields. On the basis of control experiments, a two-cycle mechanism is proposed which involves the Sonogashira coupling of 2-iodo derivatives with alkynes and the subsequent cyclization of the corresponding 2-alkynyl compounds.
One-pot synthesis of 2,3-disubstituted benzofurans from 2-chlorophenols using palladium–dihydroxyterphenylphosphine catalyst
Yamaguchi, Miyuki,Ozawa, Hayato,Katsumata, Haruka,Akiyama, Tomoyo,Manabe, Kei
supporting information, p. 3175 - 3178 (2018/07/15)
2,3-Disubstituted benzofurans possessing 2-hydroxyphenyl moiety at the C-3 position were synthesized from readily available 2-chlorophenols and terminal alkynes by hydroxy-directed ortho-Sonogashira coupling and subsequent oxypalladation/reductive elimina
One-pot synthesis of substituted benzo[b]furans from mono- and dichlorophenols using palladium catalysts bearing dihydroxyterphenylphosphine
Yamaguchi, Miyuki,Katsumata, Haruka,Manabe, Kei
, p. 9270 - 9281 (2013/10/08)
A dihydroxyterphenylphosphine bearing cyclohexyl groups on the phosphorus atom (Cy-DHTP) was found to be a powerful ligand for the palladium-catalyzed one-pot synthesis of substituted benzo[b]furans from 2-chlorophenols and terminal alkynes. This catalyst
Heterocycles by PtCl2-catalyzed intramolecular carboalkoxylation or carboamination of alkynes
Fuerstner, Alois,Davies, Paul W.
, p. 15024 - 15025 (2007/10/03)
PtCl2 constitutes a convenient catalyst for intramolecular hydroalkoxylation, carboalkoxylation, hydroamination, and carboamination reactions of alkynes, effecting the formation of substituted benzo[b]furan, indole-, and isochromene-1-one derivatives, respectively. This procedure allows for the transfer of (substituted) allyl, methoxymethyl (MOM), benzyloxymethyl (BOM), and (trimethylsilyl)ethoxymethyl (SEM) groups from oxygen to carbon and is compatible with functional groups that are susceptible to oxidative insertion of low valent metal species previously used for similar purposes. Although some of the reactions can even be carried out in air, the rates are significantly increased when conducted under an atmosphere of CO. A mechanistic rationale is proposed, implying activation of the alkyne by the carbophilic Pt(2+) template as the primary step of the catalytic cycle. Copyright
Synthesis of 2-substituted benzofurans and indoles using functionalized titanium benzylidene reagents on solid phase
Macleod, Calum,McKiernan, Gordon J.,Guthrie, Emma J.,Farrugia, Louis J.,Hamprecht, Dieter W.,Macritchie, Jackie,Hartley, Richard C.
, p. 387 - 401 (2007/10/03)
Titanium(IV) benzylidenes bearing a masked oxygen or nitrogen nucleophile in the ortho position were generated from thioacetals, using low-valent titanocene complex, Cp2Ti[P(OEt)3]2. Methylene acetal, alkyl ether, silyl ether, fluoro, tertiary amino, and N-alkyl, N-benzyl, N-prenyl, and N-silyl tert-butyl carbamate groups were tolerated in the titanium alkylidene reagents (Schrock carbenes). Aryl-chlorine bonds were stable to the titanium benzylidene functionality, but there was poor chemoselectivity for the reduction of the thioacetal in the presence of an aryl chloride. The titanium benzylidenes converted Merrifield and Wang resin-bound esters into enol ethers. The oxygen nucleophile was masked as a TMS ether, and when the resin-bound enol ethers bearing this ortho substituent were treated with 1% TFA in dichloromethane, benzofurans were released from resin in high yields. The chameleon catch strategy ensured excellent purity. In a similar way, N-alkylated and N-silylated tert-butyl carbamates were used for the synthesis of N-alkyl and N-Boc indoles, respectively. These traceless solid-phase syntheses of heterocycles are believed to involve post-cleavage modification rather than cyclative termination.
Alkylidenation of esters on solid support and traceless synthesis of 2- substituted benzofurans
Guthrie, Emma J.,MacRitchie, Jackie,Hartley, Richard C.
, p. 4987 - 4990 (2007/10/03)
Polymer-supported esters are smoothly converted into enol ethers using a titanocene alkylidene prepared by treatment of 2-tert- butyldimethylsilyloxybenzaldehyde diphenyldithioacetal with the low valent titanium species Cp2Ti[P(OEt)3]2. Treatment of the enol ethers with acid leads to the release of ketones from the Wang resin in high yield. Traceless solid-phase synthesis of 2-substituted benzofurans is achieved in a three- step termination procedure. (C) 2000 Published by Elsevier Science Ltd.
