1889-74-3Relevant academic research and scientific papers
Metal Free, Direct and Selective Deoxygenation of α-Hydroxy Carbonyl Compounds: Access to α,α-Diaryl Carbonyl Compounds
Kumar, Anil,Sandeep,Venugopalan, Paloth
, (2020/04/27)
An efficient, metal free, direct and selective deoxygenation of α-hydroxy carbonyl compounds is achieved with the aid of catalytic amount of aqueous HClO4 (70 %) and triethylsilane as hydride source. A variety of α-hydroxy-α,α-diaryl carbonyl compounds are selectively deoxygenated to give α,α-diaryl carbonyl compounds in good to excellent yields. Intermediacy of α-keto carbenium ion is proposed on the basis of some control experiments and atmospheric pressure chemical ionization mass spectral analysis.
Electrochemical [4+2] Annulation-Rearrangement-Aromatization of Styrenes: Synthesis of Naphthalene Derivatives
Ma, Yueyue,Lv, Jufeng,Liu, Chengyu,Yao, Xiantong,Yan, Guoming,Yu, Wei,Ye, Jinxing
supporting information, p. 6756 - 6760 (2019/04/17)
We report the first electrochemical strategy to synthesize functionalized naphthalene derivatives through [4+2] annulation—rearrangement–aromatization from styrenes under mild conditions. The electrolysis does not require metals, oxidants and high valence substrates, indicating the atom and step-economy ideals. The dehydrodimer produced through [4+2] cycloaddition of 4-methoxy α-methyl styrene is isolated and proved to be the key intermediate for the following oxydehydrogenation to form carbon cation, which undergoes rearrangement–aromatization to afford the final products. This reaction represents a powerful access to construct multi-substituted naphthalene blocks in a single step.
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.).
Hydrogen bond donor solvents enabled metal and halogen-free Friedel–Crafts acylations with virtually no waste stream
Liu, Guangchang,Xu, Bo
supporting information, p. 869 - 872 (2018/02/09)
We have developed a metal and halogen-free Friedel–Crafts acylation protocol with virtually no waste stream generation. We propose a hydrogen bonding donor solvent will form a hydrogen bonding network and may provide significant rate enhancement for Friedel–Crafts reactions. Trifluoroacetic acid is one of the strongest H-bond donor solvents, which is also volatile and can be easily recovered by distillation without need for reaction workup. Our protocol is a ‘green’ Friedel–Crafts acylation process: 1) the catalyst can be recovered and reused; 2) using halogen free starting material (carboxylic acids anhydride or carboxylic acids); 3) no need for aqueous reaction work-up; 4) minimum or no waste steam generation.
Why are vinyl cations sluggish electrophiles?
Byrne, Peter A.,Kobayashi, Shinjiro,Würthwein, Ernst-Urich,Ammer, Johannes,Mayr, Herbert
supporting information, p. 1499 - 1511 (2017/02/10)
The kinetics of the reactions of the vinyl cations 2 [Ph2C=C+-(4-MeO-C6H4)] and 3 [Me2C=C+-(4-MeO-C6H4)] (generated by laser flash photolysis) with diverse nucleophile
Reaction of selenium dioxide with aromatic ketones in the presence of boron triflouride etherate: A protocol for the synthesis of triarylethanones
Laloo, Badaker M.,Mecadon, Hormi,Rohman, Md. Rumum,Kharbangar, Iadeishisha,Kharkongor, Icydora,Rajbangshi, Mantu,Nongkhlaw, Rishanlang,Myrboh, Bekington
experimental part, p. 707 - 712 (2012/02/16)
An efficient regioselective protocol for the C-C bond formation by the unexpected α,α-diarylation of aromatic ketones with unactivated arenes in the presence of selenium dioxide and boron trifluoride etherate has been developed. The generality and functio
Reductive cross-coupling between N-acylbenzimidazoles and diarylketones promoted by Sm/TiCl4
Du, Jingxing,Wang, Xiaoxia,Zheng, Renwei
, p. 14 - 15 (2007/10/03)
The reductive cross-coupling reaction between N-acylbenzimidazoles and diarylketones promoted by Sm/TiCl4 was performed in refluxing THF under a nitrogen atmosphere, to give 1,2,2-triaryl ethanones in moderate to good yields.
Low-valent titanium promoted self-coupling of N-acylbenzotriazoles and their cross-coupling with diarylketones
Wang, Xiaoxia,Zhang, Yongmin
, p. 2627 - 2634 (2007/10/03)
The self-coupling reaction of N-acylbenzotriazoles and their cross-coupling with diarylketones promoted by Sm/TiCl4 system were investigated. Self-coupling reaction could afford α-diketones or benzoins in moderate yields, while the cross-coupli
Highly regioselective, sequential, and multiple palladium-catalyzed arylations of vinyl ethers carrying a coordinating auxiliary: An example of a heck triarylation process
Nilsson,Larhed,Hallberg
, p. 8217 - 8225 (2007/10/03)
This article describes the development of new auxiliary-accelerated Heck multiarylations by intramolecular presentation of the oxidative addition complex. The introduction of a specific, palladium-coordinating dimethylamino group allows for the desired chelation-accelerated and chelation-controlled tri- and diarylation reactions. We report (a) the first example of a Heck triarylation process, (b) highly selective palladium-catalyzed diarylations of alkyl vinyl ethers, and (c) a very rapid two-phase protocol for the microwave-assisted hydrolysis of amino-substituted, arylated vinyl ethers constituting an entry to diarylated ethanals and substituted desoxybenzoins. X-ray structures and product patterns support the suggested substrate-controlled Heck reaction pathway. The catalyst-directing alkyl dimethylamino functionality was rapidly (1-2 min) and efficiently released by microwave hydrolysis after Heck multiarylation reactions. The liberated aromatic carbonyl compounds were thereafter isolated and fully characterized.
Intermolecular Reductive Cross Coupling of Carbonyl Compounds with Nitriles Induced by Low-valent Titanium
Gao, Ju,Hu, Ming-yang,Chen, Jian-xie,Yuan, Su,Chen, Wei-xing
, p. 1617 - 1620 (2007/10/02)
Intermolecular cross coupling of carbonyl compounds with nitriles promoted by TiCl4-Zn leads to ketones.
