1503-86-2Relevant articles and documents
An efficient protocol for alcohol protection under solvent- and catalyst-free conditions
Rao, Ch. Bhujanga,Chinnababu,Venkateswarlu
, p. 8856 - 8858 (2009)
(Chemical Equation Presented) Asimple and highly efficient protocol for pivaloylation of alcohols without using a catalyst under solvent-free conditions has been developed. The key advantages of the reaction are short reaction time, high yields, simple workup, and no need for further purification. Selectivity was observed between primary alcohols vs. secondary alcohols and aliphatic alcohols vs. aromatic alcohols. The accentuated and relevant phenomenon of this method that we observed is in one-pot conversion of TBS protection into Piv protection of the hydroxyl group. 2009 American Chemical Society.
Regioselective Ortho‐C–H sulfenylation of free phenols catalyzed by Co(II)-immobilized on silica-coated magnetic nanoparticles
Khaef, Sepideh,Rostami, Abed,Khakyzadeh, Vahid,Zolfigol, Mohammad Ali,Taherpour, Avat Arman,Yarie, Meysam
, (2020/01/22)
Fe3O4?SiO2-UT?CoII is prepared by the silica-coated magnetic nanoparticles, urea-triazole, and CoCl2. This organic-inorganic hybride composite showed a good to excellent catalytic activity toward regioselective ortho-sulfenylation of free phenols and naphthols using pivalic anhydride as a directing group, also K2S2O8 and PPh3 were employed as oxidant and additive respectively. The newly synthesized catalyst was fully characterized by using different techniques such as FT-IR, TGA, DTG, TEM, SEM, EDS, ICP and VSM analyses. The competitive price, accessibility and lower toxicity of cobalt compared to expensive transition metals using for C–H bond activation and functionalization constitute precious advantages for this method. Moreover, this heterogeneous catalyst could be magnetically recovered and reused without significant loss of its catalytic activity after five cycles.
Nickel-Mediated Trifluoromethylation of Phenol Derivatives by Aryl C?O Bond Activation
Hu, Wei-Qiang,Pan, Shen,Qing, Feng-Ling,Vicic, David A.,Xu, Xiu-Hua
supporting information, p. 16076 - 16082 (2020/07/04)
The increasing pharmaceutical importance of trifluoromethylarenes has stimulated the development of more efficient trifluoromethylation reactions. Tremendous efforts have focused on copper- and palladium-mediated/catalyzed trifluoromethylation of aryl halides. In contrast, no general method exists for the conversion of widely available inert electrophiles, such as phenol derivatives, into the corresponding trifluoromethylated arenes. Reported herein is a practical nickel-mediated trifluoromethylation of phenol derivatives with readily available trimethyl(trifluoromethyl)silane (TMSCF3). The strategy relies on PMe3-promoted oxidative addition and transmetalation, and CCl3CN-induced reductive elimination. The broad utility of this transformation has been demonstrated through the direct incorporation of trifluoromethyl into aromatic and heteroaromatic systems, including biorelevant compounds.
Chemoselective Cross-Coupling between Two Different and Unactivated C(aryl)-O Bonds Enabled by Chromium Catalysis
Tang, Jinghua,Liu, Liu Leo,Yang, Shangru,Cong, Xuefeng,Luo, Meiming,Zeng, Xiaoming
supporting information, p. 7715 - 7720 (2020/05/20)
We report here the first example of cross-coupling between two different and unactivated C(aryl)-O bonds with chromium catalysis. The combination of a low-cost Cr(II) salt, 4,4′-di-tert-butyl-2,2′-dipyridyl (dtbpy) as the ligand, and magnesium as the reductant shows high reactivity in promoting the reductive cross-coupling of aryl methyl ether derivatives with aryl esters by cleavage and coupling of two different C(aryl)-O bonds under mild conditions. The formation of active low-valent Cr species by reduction of CrCl2 with Mg can be considered, which prefers to initially activate the C(aryl)-O bond of phenyl methyl ether with the chelation help of dtbpy and an o-imine auxiliary. The subsequent consecutive reduction, second C(aryl)-O activation, and reductive elimination allow for the achievement of selective cross-coupling of C(aryl)-O/C(aryl)-O bonds.
Reductive Cross-Coupling between Unactivated C(aryl)-N and C(aryl)-O Bonds by Chromium Catalysis Using a Bipyridyl Ligand
Cong, Xuefeng,Fan, Fei,Luo, Meiming,Tang, Jinghua,Zeng, Xiaoming,Zhao, Lixing
supporting information, p. 12834 - 12840 (2020/08/21)
Reductive cross-coupling between two chemically inert bonds remains a great challenge in synthetic chemistry. We report here the reductive cross-coupling between unactivated C(aryl)-N and C(aryl)-O bonds that was achieved by chromium catalysis. The simple and inexpensive CrCl2 salt, combined with important bipyridyl ligand and magnesium reductant, shows high reactivity in the successive cleavage of C(aryl)-N bonds of aniline derivatives and C(aryl)-O bonds of aryl esters, allowing the cross-coupling of these two unactivated and different bonds to occur in a reductive fashion to form a C(aryl)-C(aryl) bond. Mechanistic studies by deuterium-labeling experiments indicate that the C(aryl)-N bonds in anilines are preferentially cleaved by reactive Cr species, in which the ligation of bipyridyl with Cr by adopting a coordination model in 1:1 ratio can be considered.
Iodine(III)-Mediated, Controlled Di- or Monoiodination of Phenols
Satkar, Yuvraj,Yera-Ledesma, Luisa F.,Mali, Narendra,Patil, Dipak,Segura-Quezada, Luis A.,Ramírez-Morales, Perla I.,Solorio-Alvarado, César R.,Navarro-Santos, Pedro
, p. 4149 - 4164 (2019/04/30)
An oxidative procedure for the electrophilic iodination of phenols was developed by using iodosylbenzene as a nontoxic iodine(III)-based oxidant and ammonium iodide as a cheap iodine atom source. A totally controlled monoiodination was achieved by buffering the reaction medium with K3PO4. This protocol proceeds with short reaction times, at mild temperatures, in an open flask, and generally with high yields. Gram-scale reactions, as well as the scope of this protocol, were explored with electron-rich and electron-poor phenols as well as heterocycles. Quantum chemistry calculations revealed PhII(OH)·NH3 to be the most plausible iodinating active species as a reactive "I+" synthon. In light of the relevance of the iodoarene moiety, we present herein a practical, efficient, and simple procedure with a broad functional group scope that allows access to the iodoarene core unit.
Efficient and selective hydrogenation of C-O bonds with a simple sodium formate catalyzed by nickel
Xi, Xiaoxiang,Chen, Tieqiao,Zhang, Ji-Shu,Han, Li-Biao
supporting information, p. 1521 - 1524 (2018/02/19)
A Ni-catalyzed hydrogenation of C-O compounds with sodium formate is developed. Various esters, i.e. aryl, alkenyl, benzyl pivalates, and even the aryl ethers, were efficiently reduced with a loading of nickel catalysts down to 0.5 mol%. Reactive functional groups such as C-C double bonds, carbonyl, CN, MeS and halogen groups are tolerable. This reaction can be used for the modification of complex molecules and carried out at a large scale.
Ni-Catalyzed Decarboxylative Cross-Coupling of Potassium Polyfluorobenzoates with Unactivated Phenol and Phenylmethanol Derivatives
Chen, Quan,Wu, Aizhen,Qin, Shengxiang,Zeng, Meiqi,Le, Zhiping,Yan, Zhaohua,Zhang, Hua
supporting information, p. 3239 - 3244 (2018/09/10)
A Ni-catalyzed decarboxylative cross-coupling of potassium polyfluorobenzoates with unactivated phenol and phenylmethanol derivatives is described. This novel transformation provides a practical and efficient protocol towards the synthesis of important polyfluorobiaryls and polyfluorinated diarylmethanes, and greatly enlarges the range of electrophiles utilized in decarboxylative coupling. Remarkably, preliminary mechanistic studies indicated the essential role of Zn(OAc)2 might lie in the enhancement of decarboxylation step. (Figure presented.).
Preparation method of aryl carboxylate compound based on alkenyl carboxylate ester exchange reaction
-
Paragraph 0049; 0050; 0051, (2018/10/11)
The invention provides a preparation method of an aryl carboxylate compound based on alkenyl carboxylate ester exchange reaction and belongs to the technical field of pharmaceutical chemical intermediates and related chemistry. According to the method, phenol and alkenyl carboxylate are used as raw materials and green and efficient synthesis of the aryl carboxylate compound is realized under the catalysis effect of alkali. The method has the advantages of high selectivity, moderate reaction conditions, good functional group compatibility, wide substrate range, environment friendliness and thelike. The aryl carboxylate compound is an important organic synthetic intermediate and has very wide application in the fields of organic synthesis and pharmacology, so that the preparation method hasvery great application value and social economic benefits.
Na 2 CO 3-Catalyzed O-Acylation of Phenols for the Synthesis of Aryl Carboxylates with Use of Alkenyl Carboxylates
Zhou, Xiao-Yu,Chen, Xia
supporting information, p. 2321 - 2325 (2018/10/20)
Inorganic base-catalyzed O-acylation of phenol and its derivatives has been developed. The procedure provides an efficient catalysis system for the preparation of aryl carboxylates with alkenyl carboxylates as acyl reagents. The reaction proceeded smoothly by using ?-Na 2 CO 3 as the catalyst in MeCN to produce the corresponding aryl carboxylates in good to excellent yields.
