2039-77-2Relevant academic research and scientific papers
Concise Synthesis of Polysubstituted Carbohelicenes by a C?H Activation/Radical Reaction/C?H Activation Sequence
Yin, Jiangliang,You, Jingsong
, p. 302 - 306 (2019)
Disclosed herein is the merging of C?H activation and radical chemistry, enabling rapid access to a structurally diverse family of fused carbohelicenes through the fusion of α-acetylnaphthalenes with alkynes under oxidative conditions. This cascade process exhibits exquisite chemoselectivity and regioselectivity. The reaction pathway was analyzed by intermediate separations, control experiments, radical trapping, EPR, MALDI-TOF-MS, and ESI-HRMS experiments, and shown to involve a C2?H activation/radical reaction/C8?H activation relay.
Aqueous α-Arylation of Mono- and Diarylethanone Enolates at Low Catalyst Loading
Astarloa, Iratxe,SanMartin, Raul,Herrero, María Teresa,Domínguez, Esther
supporting information, p. 1711 - 1718 (2018/03/21)
Acetophenone and deoxybenzoin derivatives are selectively α-arylated using a combination of very small amounts of palladium acetate and diphenylphosphine oxide as catalyst system and water as the only solvent. Target di- and triarylethanones are isolated virtually free of metal residues, and the reaction is amenable to gram-scale. A mechanistic proposal based on TEM images, poisoning experiments, kinetic plot and ESI-MS spectrometry is also provided. (Figure presented.).
Hydration of aromatic alkynes catalyzed by a self-assembled hexameric organic capsule
La Sorella, Giorgio,Sperni, Laura,Ballester, Pablo,Strukul, Giorgio,Scarso, Alessandro
, p. 6031 - 6036 (2016/08/05)
The combination of a Br?nsted acid catalyst and a supramolecular organic capsule formed by the self-assembly of six resorcin[4]arene units efficiently promotes the mild hydration of aromatic alkynes to their corresponding ketones. The capsule provides a suitable nanoenvironment that favors protonation of the substrate and addition of water.
Hydration of aromatic terminal alkynes catalyzed by iron(III) sulfate hydrate under chlorine-free conditions
Bassetti, Mauro,Ciceri, Samuele,Lancia, Federico,Pasquini, Chiara
supporting information, p. 1608 - 1612 (2014/03/21)
The hydration of aromatic terminal alkynes performed in acetic acid in the presence of catalytic hydrate ironIII sulfate, Fe2(SO 4)3·nH2O (4-9 mol %), yields the derived aryl methyl ketones with good to excellent yields. Under comparable conditions (18 mol %, 95 C, 24 h), bifunctional substrates were transformed into the monoacetyl or the diacetyl derivatives, depending on the structure of the aromatic diyne. The reaction is compatible with aryl substituents of different nature and ring positions, including hydroxyl, carbonyl groups, and cumulated hydrocarbons. The soft character of the non nucleophilic sulfate anion allows for activation of the triple bond toward carbonoxygen bond formation in the Br?nsted acidic medium. The proposed protocol is based on readily available and non toxic materials, in the absence of chlorine atoms in either the solvent or the metal catalyst.
Direct one-pot synthesis of phenanthrenes via Suzuki-Miyaura coupling/aldol condensation cascade reaction
Young, Ha Kim,Lee, Hyuk,Yeong, Joon Kim,Bum, Tae Kim,Heo, Jung-Nyoung
, p. 495 - 501 (2008/09/17)
(Chemical Equation Presented) We have developed an efficient cascade reaction, a Suzuki-Miyaura coupling followed by an aldol condensation, for the construction of phenanthrene derivatives using microwave irradiation. For example, the reaction of methyl 2-bromophenylacetamide with 2- formylphenylboronic acid in the presence of a palladium catalyst and a base provided a biaryl intermediate, which underwent in situ cyclization to afford the corresponding phenanthrene in high yield.
Palladium-catalyzed reaction of aryl iodides with acetic anhydride. A carbon monoxide-free synthesis of acetophenones
Cacchi, Sandro,Fabrizi, Giancarlo,Gavazza, Federica,Goggiamani, Antonella
, p. 289 - 291 (2007/10/03)
(Matrix presented) The palladium-catalyzed reaction of aryl iodides with acetic anhydride provides a straightforward and experimentally simple carbon monoxide-free route to acetophenones. The reaction tolerates a wide range of funcfionalized aryl iodides. Acetophenones are isolated in excellent yield with a variety of neutral, slightly electron-rich, and slightly electron-poor aryl iodides, whereas moderate yields are obtained with aryl iodides containing strongly electron-withdrawing substituents.
Friedel-Crafts reactions in room temperature ionic liquids
Adams, Christopher J.,Earle, Martyn J.,Roberts, Glyn,Seddon, Kenneth R.
, p. 2097 - 2098 (2007/10/03)
Friedel-Crafts reactions in the ionic liquid system 1-methyl-3-ethylimidazolium chloride-aluminium(III) chloride can be performed with excellent yields and selectivities, and in the case of anthracene, have been found to be reversible.
Radical cyclization reactions of α-silyl amine α,β-unsaturated ketone and ester systems promoted by single electron transfer photosensitization
Jeon, Yoon T.,Lee, Chao-Pin,Mariano, Patrick S.
, p. 8847 - 8863 (2007/10/02)
The results of a broad investigation of the preparative and mechanistic aspects of single electron transfer (SET) promoted photocyclization reactions of α-silyl amino and amido α,β-unsaturated esters and ketones are presented. A number of unique and synthetically useful features of these processes, driven by α-silyl amine and amide cation radical desilylation and by intramolecular conjugate addition of intermediate α-amino and α-amido carbon-centered radicals to unsaturated esters and ketones, are described. Comparisons of the SET-sensitized and direct irradiation promoted reactions of these systems have shown how the former method is superior in inducing photocyclization reactions in cases where the α,β-unsaturated ketone or ester excited states are too reactive to be quenched by SET from the tethered amine donors and where diradicals produced as intermediates in the direct-irradiation reactions undergo fragmentation rather than cyclization. The current efforts have also demonstrated that problems associated with the ready oxidation of intermediate α-amino radicals can be avoided by the proper selection of photosensitizer or amine N substituents. Lastly, the synthetic versatility of this chemistry, exemplified by its application to the preparation of a number of N-heterocyclic substances by pathways involving either exo or endo radical cyclization, is presented.
On the Acetylation of Phenanthrene and 9-Chlorphenanthrene
Fernandez, Franco,Gomez, Generosa,Lopez, Carmen,Santos, Ana
, p. 15 - 21 (2007/10/02)
Friedel-Crafts acetylation of phenanthrene (1a) in sym-tetrachlorethane yields mixtures of 2-,3- and 9-acetylphenanthrenes (2a,3a,4).The distribution of isomers is found to depend strongly upon the method of mixing the reagents.Acetylation of 9-chlorophenanthrene (1b), perfomed by a variety of methods and solvents, led mainly to 3-acetyl-9-chlorophenanthrene (3b) (>/=85percent).Previously unreported 2-acetyl-9-chlorophenanthrene (2b) was found to form up to a maximum 11percent in nitrobenzene.
