4072-08-6Relevant academic research and scientific papers
Aerobic Copper-Catalyzed Salicylaldehydic Cformyl?H Arylations with Arylboronic Acids
Xiao, Lin,Lang, Tao-Tao,Jiang, Ying,Zang, Zhong-Lin,Zhou, Cheng-He,Cai, Gui-Xin
supporting information, p. 3278 - 3283 (2021/02/01)
We report a challenging copper-catalyzed Cformyl?H arylation of salicylaldehydes with arylboronic acids that involves unique salicylaldehydic copper species that differ from reported salicylaldehydic rhodacycles and palladacycles. This protocol has high chemoselectivity for the Cformyl?H bond compared to the phenolic O?H bond involving copper catalysis under high reaction temperatures. This approach is compatible with a wide range of salicylaldehyde and arylboronic acid substrates, including estrone and carbazole derivatives, which leads to the corresponding arylation products. Mechanistic studies show that the 2-hydroxy group of the salicylaldehyde substrate triggers the formation of salicylaldehydic copper complexes through a CuI/CuII/CuIII catalytic cycle.
RhIII-Catalyzed Decarboxylative o-Acylation of Arenes Bearing an Oxidizing Directing Group
Bera, Suvankar,Chandrasekhar,Chatterjee, Satadru,Killi, Sunil Kumar,Sarkar, Debabrata,Banerji, Biswadip
, p. 3877 - 3881 (2019/06/28)
Here in we report, rhodium(III)-catalyzed decarboxylative acylation of arenes using α-oxocarboxylic acids as acyl surrogate. In this strategy, O–NHAc group act as an autocleavable oxidizing directing group (ODGauto), thus giving rise to ortho-acylated phenols in moderate to good yields. Mechanistic studies provided strong support for a kinetically relevant C–H bond activation. According to the best of our knowledge, this is the first report of Rhodium catalyzed decarboxylative acylation.
Acylation of Csp2-H bond with acyl sources derived from alkynes: Rh-Cu bimetallic catalyzed CC bond cleavage
Xie, Ying
, p. 12372 - 12375 (2016/10/22)
A Rh-Cu bimetallic catalyzed o-acylation of acyloxacetamide with alkynes has been described. This transformation provides a novel, concise way to synthesize ortho-acylphenols using functionalized alkynes as acylating reagents. Mechanistic studies revealed a Rh-Cu relay process, in which O2 plays a critical role for the formation of carbonyl compounds.
One-pot synthesis of 3,4-disubstituted coumarins under catalysis of Mn 3O4 nanoparticles
Sun, Huayin,Zhang, Yonghui,Guo, Fengfeng,Yan, Yizhe,Wan, Changfeng,Zha, Zhenggen,Wang, Zhiyong
supporting information; experimental part, p. 480 - 483 (2012/03/09)
The one-pot synthesis of 3,4-disubstituted coumarins from substituted 2-(hydroxymethyl)phenols with β-keto esters catalyzed by Mn 3O4 nanoparticles was developed. A series of 3,4-disubstituted coumarin derivatives were obtained in good yields. A new method for the one-pot synthesis of 3,4-disubstituted coumarins from substituted 2-(hydroxymethyl)phenols with β-keto esters catalyzed by Mn 3O4 nanoparticles has been developed. A series of 3,4-disubstituted coumarin derivatives were synthesized from substituted 2-(hydroxymethyl)phenols and β-keto esters in good yields. Copyright
Fries rearrangement in ionic melts
Harjani, Jitendra R.,Nara, Susheel J.,Salunkhe, Manikrao M.
, p. 1979 - 1981 (2007/10/03)
1-Butyl-3-methylimidazolium chloroaluminate, [BMIm]+Al2Cl7-, was used as a solvent as well as a Lewis acid catalyst in Fries rearrangement reactions of phenyl benzoates. The rate of consumption of phenyl benzoate obeyed first-order kinetics. Good yields and high selectivity are the features observed in this unconventional but interesting aprotic solvent.
Alumina in Methanesulfonic Acid (AMA) as a New Efficient Reagent for Direct Acylation of Phenol Derivatives and Fries Rearrangement. A Convenient Synthesis of o-Hydroxyarylketones
Sharghi, Hashem,Kaboudin, Babak
, p. 2678 - 2695 (2007/10/03)
Alumina in methanesulfonic acid (AMA) is used to prepare o-hydroxyaryl ketones by acylation of phenol and naphthol derivatives with carboxylic acids and the Fries rearrangement of phenolic esters. Mechanistic studies show that the acylation reaction in AMA occurred through an esterification followed by a Fries rearrangement of the phenolic ester by an intermolecular mechanism.
Buttressing Effect in Carbene Chemistry. Effect of 3-Alkyl Groups on the Reactions of 2-Alkoxydiphenylcarbenes
Tomioka, Hideo,Kimoto, Kohji,Murata, Hiroshi,Izawa, Yasuji
, p. 471 - 477 (2007/10/02)
Irradiation of 2-methoxydiphenyldiazomethane 1a in diethyl ether at 10 deg C gave 3-phenyldihydrobenzofuran 3a along with a small amount of the ether adduct 4a, which became the major product when the irradiation was carried out in the ether matrix at -196 deg C.The reaction patterns were dramatically changed as an alkyl group was introduced into the 3-position of substrates 1.Thus, irradiation of 2-methoxy-3-alkyldiphenyldiazomethanes 1b-d in diethyl ether either at 10 deg C or at -196 deg C afforded the corresponding benzofurans 3b-d at the complete expense of the ether adducts 4b-d.The results are nicely explained in terms of the buttressing effect of the 3-alkyl group, which prevents the 2-methoxy group from lying in the plane of the phenyl ring in the precursor molecules and assists the methoxy group in rotating around the C-O bond toward the carbene centre after elimination of N2.Generation of carbenes 2 in methanol at 10 deg C produced O-H insertion adducts 5 as the major product at the expense of benzofurans 3.The ether 5a was formed as a major product in the reaction of carbene 2a with the alcohol matrix at -196 deg C, but the benzofurans 3 became the major product in the irradiation of substrates 1b-d in methanol matrix at -196 deg C.The results are again explicable in terms of the buttressing effect of 3-alkyl substituents on the relative populations of thew rotational isomers of the carbenes 2.The effect of the 3-alkyl group on the reaction of 2,2',5'-trimethoxydiphenylcarbenes 7 which form two kinds of intramolecular C-H insertion products 8 and 9 were studied and the results are again discussed in terms of the buttressing effect.
Antianaphylactic Benzophenones and Related Compounds
Evans, Delme,Cracknell, Mark E.,Saunders, John C.,Smith, Christine E.,Williamson, W. R. Nigel,et al.
, p. 1321 - 1327 (2007/10/02)
The synthesis and biological properties of 85 benzophenones and related compounds are described.The majority of the compounds inhibit the release of leukotrienes (LT) C4 and D4 in vitro from sensitized guinea pig chopped lung.In addition, some of the compounds inhibited the release of LTs from passively sensitized human chopped lung and protected guinea pigs from the effects of anaphylaxis in a modified Herxheimer test.
