3407-15-6Relevant academic research and scientific papers
Synthesis of Indole/Benzofuran-Containing Diarylmethanes through Palladium-Catalyzed Reaction of Indolylmethyl or Benzofuranylmethyl Acetates with Boronic Acids
Arcadi, Antonio,Calcaterra, Andrea,Chiarini, Marco,Fabrizi, Giancarlo,Fochetti, Andrea,Goggiamani, Antonella,Iazzetti, Antonia,Marrone, Federico,Marsicano, Vincenzo,Serraiocco, Andrea
supporting information, p. 741 - 753 (2021/11/26)
The palladium-catalyzed synthesis of indole/benzofurancontaining diarylmethanes starting from indolylmethyl or benzofuranylmethyl acetates with boronic acids has been investigated. The success of the reaction is influenced by the choice of precatalyst: with indolylmethyl acetates the reaction works well with [Pd(η3-C3H5)Cl]2/XPhos while with benzofuranylmethyl acetates Pd2(dba)3/XPhos is more efficient. The good to high yields and the simplicity of the experimental procedure make this protocol a versatile synthetic tool for the preparation of 2- and 3-substituted indoles and 2-benzo[b]furans. The methodology can be advantageously extended to the preparation of a key precursor of Zafirlukast.
Highly Efficient Enantioselective Synthesis of Chiral Sulfones by Rh-Catalyzed Asymmetric Hydrogenation
Yan, Qiaozhi,Xiao, Guiying,Wang, Ying,Zi, Guofu,Zhang, Zhanbin,Hou, Guohua
supporting information, p. 1749 - 1756 (2019/01/25)
A highly efficient and enantioselective Rh-(R,R)-f-spiroPhos complex catalyzed hydrogenation of a series of unsaturated sulfones has been developed. With Rh-(R,R)-f-spiroPhos catalyst under mild conditions, not only the asymmetric hydrogenation of both the 3,3-diaryl and exocyclic α,β-unsaturated sulfones was first realized with up to 99.9% ee but also 3-alkyl-3-aryl and benzo[b]thiophene-1,1-dioxides were successfully hydrogenated to the corresponding chiral sulfones with excellent enantioselectivities (up to 99.4% ee) regardless of the steric hindrance, electronic property, and geometry of the substrates. Moreover, this reaction offers a route to (S)-(+)-ar-turmerone as a spice flavor, which is an important synthetic intermediate of pharmaceuticals.
Dearomative Dienolate-Mediated Catalysis: A Remote Activation Strategy for Asymmetric Functionalization of Benzylic C-H Bonds of Heteroaryl Aldehydes
Wang, Yang,Lin, Jun-Bing,Xie, Ji-Kang,Lu, Hong,Hu, Xiu-Qin,Xu, Peng-Fei
, p. 5835 - 5839 (2018/09/25)
A dearomative remote activation strategy for the asymmetric functionalization of benzylic C-H bonds of heteroaryl aldehydes under bifunctional Br?nsted base catalysis has been developed. The in situ generated o-QDMs-type dienolate intermediates were effic
Iridium-Catalyzed Asymmetric Hydrogenation of Benzo[b]thiophene 1,1-Dioxides
Tosatti, Paolo,Pfaltz, Andreas
supporting information, p. 4579 - 4582 (2017/04/11)
An efficient iridium-catalyzed asymmetric hydrogenation of substituted benzothiophene 1,1-dioxides is described. The use of iridium complexes with chiral pyridyl phosphinite ligands provides access to highly enantiomerically enriched sulfones with substituents at the 2- and 3-position. Sulfones of this type are of interest as core structures of agrochemicals and pharmaceuticals. Moreover, they can be further reduced to chiral 2,3-dihydrobenzothiophenes.
A Zwitterionic Palladium(II) Complex as a Precatalyst for Neat-Water-Mediated Cross-Coupling Reactions of Heteroaryl, Benzyl, and Aryl Acid Chlorides with Organoboron Reagents
Ramakrishna, Visannagari,Rani, Morla Jhansi,Reddy, Nareddula Dastagiri
, p. 7238 - 7255 (2018/01/01)
The Suzuki–Miyaura cross-coupling (SMC) reactions of several heteroaryl chlorides, benzyl chlorides, and aryl acid chlorides with (hetero)arylboron reagents have been investigated in the presence of [Pd(HL1)(PPh3)Cl2] (I) [HL1 = 3-[(2,6-diisopropylphenyl)-1-imidazolio]-2-quinoxalinide] as catalyst and K2CO3 as base in neat water. The synthesis of the heterocycle-containing biaryls required the addition of 2 mol-% of a phosphine ligand (PPh3 or X-Phos). A combination of more than 115 substrates were screened and it was found that I is a versatile catalyst that can produce heterocycle-containing biaryls, diarylmethanes, and benzophenones in moderate-to-excellent yields.
Synthesis of zwitterionic palladium complexes and their application as catalysts in cross-coupling reactions of aryl, heteroaryl and benzyl bromides with organoboron reagents in neat water
Ramakrishna,Dastagiri Reddy
, p. 8598 - 8610 (2017/07/12)
N-(3-Chloro-2-quinoxalinyl)-N′-arylimidazolium salts (aryl = 2,6-diisopropylphenyl [HL1Cl]Cl, aryl = mesityl [HL2Cl]Cl) have been synthesized by treating 2,3-dichloroquinoxaline with the corresponding N′-arylimidazole in neat water. Facile reactions of these imidazolium salts with Pd(PPh3)4 and Pd2(dba)3/PPh3 (dba = dibenzyledene acetone) at 50 °C have afforded zwitterionic palladium(ii) complexes [Pd(HL1)(PPh3)Cl2] (I) and [Pd(HL2)(PPh3)Cl2] (II) in excellent yields. I and II have been tested for their ability to catalyze Suzuki-Miyaura cross coupling (SMC) reactions in neat water/K2CO3 and are found to be highly active for carrying out these reactions between aryl bromides and organoboron reagents. Furthermore, the scope of the catalyst I was also examined by employing (hetero)aryl bromides, hydrophilic aryl bromides, benzyl bromides and various organoboron reagents. More than 80 aryl/benzyl bromide-arylboronic acid combinations were screened in neat water/K2CO3 and it was found that I was a versatile catalyst, which produced biaryls/diarylmethanes in excellent yields. A TON of 82 000 was achieved by using I. Studies on the mechanism have also been carried out to investigate the involvement of carbene complexes in the catalytic path. Poison tests and a two-phase test were also conducted and the results are reported.
Synthesis of 2-Acylbenzo[b]thiophenes via Cu-Catalyzed α-C-H Functionalization of 2-Halochalcones Using Xanthate
Sangeetha, Subramani,Sekar, Govindasamy
, p. 1670 - 1673 (2017/04/11)
An efficient protocol is described for the synthesis of 2-acylbenzo[b]thiophenes from easily accessible 2-iodochalcones through α-C-H functionalization using Cu(OAc)2 catalyst and xanthate as sulfur source. Less reactive 2-bromochalcones also yielded the corresponding 2-acylbenzothiophenes in good yield. The reaction proceeds via in situ incorporation of sulfur followed by copper-catalyzed cyclization to generate 2-acylbenzothiophenes without external acyl source. The synthetic importance is showcased by synthesis of 1-(5-hydroxybenzothiophene-2-yl)ethanone, which is a known pre-mRNA splicing modulator.
The Stabilized Cation Pool Method: Metal- and Oxidant-Free Benzylic C-H/Aromatic C-H Cross-Coupling
Hayashi, Ryutaro,Shimizu, Akihiro,Yoshida, Jun-Ichi
, p. 8400 - 8403 (2016/07/27)
Electrochemical oxidation of toluene derivatives in the presence of a sulfilimine gave benzylaminosulfonium ions as stabilized benzyl cation pools, which reacted with subsequently added aromatic nucleophiles to give the corresponding cross-coupling produc
Cyclopenta[b]annulation of Heteroarenes by Organocatalytic γ′[C(sp3)?H] Functionalization of Ynones
Raghu, Moluguri,Grover, Jagdeep,Ramasastry
, p. 18316 - 18321 (2016/12/16)
A new approach for the cyclopenta[b]annulation of heteroarenes through metal-free and directing-group-free γ′[C(sp3)?H] functionalization and intramolecular hydroalkylation of ynones has been developed. In an unprecedented event, nucleophilic addition of an organophosphine to the designed ynones triggers γ′[C(sp3)?H] functionalization, leading to the formation of heteroaryl-based ortho-quinodimethane (oQDM) intermediates that undergo carbocyclization to provide cyclopentannulated heteroarenes in good yields and excellent stereoselectivities. Deuterium-labeling experiments substantiated the proposed reaction mechanism as well as the speculated epimerization.
Direct cross-coupling of benzyl alcohols to construct diarylmethanes via palladium catalysis
Cao, Zhi-Chao,Yu, Da-Gang,Zhu, Ru-Yi,Wei, Jiang-Bo,Shi, Zhang-Jie
supporting information, p. 2683 - 2686 (2015/03/05)
A direct arylation to furnish diarylmethanes from benzyl alcohols was realized through Pd(PPh3)4-catalyzed Suzuki-Miyaura coupling via benzylic C-O activation in the absence of any additives. The arylation is compatible with various functional groups. This development provides an atom- and step-economic way to approach a diarylmethane scaffold under mild and environmentally benign conditions. This journal is
