55249-73-5Relevant academic research and scientific papers
Visible light mediated oxidation of benzylic sp3 C-H bonds using catalytic 1,4-hydroquinone, or its biorenewable glucoside, arbutin, as a pre-oxidant
Finney, Laura C.,Mitchell, Lorna J.,Moody, Christopher J.
supporting information, p. 2242 - 2249 (2018/05/28)
Benzylic ethers undergo a visible light induced C-H activation and oxygen insertion to give the corresponding benzoate esters in moderate to good yields. The conditions employ substoichiometric amounts of 1,4-hydroquinone with copper(ii) chloride dihydrate as an electron-transfer mediator, oxygen as the terminal oxidant and dimethyl carbonate as solvent under visible light irradiation. The naturally occurring glucoside, arbutin, which is commercially available or can be accessed via extraction of the leaves of bearberry (Arctostaphylos uva-ursi) or elephant ears (Bergenia crassifolia) can be used as a biorenewable source of 1,4-hydroquinone. The methodology exploits the increase in oxidizing ability of quinones upon irradiation with visible light, and offers a sustainable alternative for the late stage oxidative functionalization of benzylic C-H bonds. It is applicable to a range of cyclic benzylic ethers such as isochromans and phthalans, and simple benzyl alkyl ethers. It can also be applied in the oxidation of benzylic amines into amides, and of diarylmethanes into the corresponding ketones. Mechanistic studies suggest that the reaction proceeds by H-abstraction by the photo-excited triplet benzoquinone to give a benzylic radical that subsequently reacts with molecular oxygen.
Iodine-catalyzed transformation of aryl-substituted alcohols under solvent-free and highly concentrated reaction conditions
Jereb, Marjan,Vra?i?, Dejan
, p. 747 - 762 (2018/01/17)
Iodine-catalyzed transformations of alcohols under solvent-free reaction conditions (SFRC) and under highly concentrated reaction conditions (HCRC) in the presence of various solvents were studied in order to gain insight into the behavior of the reaction intermediates under these conditions. Dimerization, dehydration and substitution were the three types of transformations observed with benzylic alcohols. Dimerization and substitution reactions were predominant in the case of primary- and secondary alcohols, whereas dehydration prevailed in the case of tertiary alcohols. The relative reactivity of substituted 1-phenylethanols in I2-catalyzed dimerization under SFRC provided a good Hammett plot ρ+ = -2.8 (r2 = 0.98), suggesting the presence of electron-deficient intermediates with a certain degree of developed charge in the rate-determining step.
Sulfated tungstate as hydroxyl group activator for preparation of benzyl, including p-methoxybenzyl ethers of alcohols and phenols
Katkar, Kamlesh V.,Veer, Sachin D.,Akamanchi, Krishnacharya G.
supporting information, p. 1893 - 1901 (2016/11/25)
Sulfated tungstate was found to be an effective heterogeneous and reusable catalyst for hydroxy group activation–mediated preparation of benzylic ethers including p-methoxybenzylic ethers of a wide range of alcohols and phenols under mild reaction conditions.
Direct synthesis of ethers from aldehydes and ketones. One-pot reductive etherification of benzaldehydes, alkyl aryl ketones, and benzophenones
Mochalov,Fedotov,Trofimova,Zefirov
, p. 503 - 512 (2016/06/13)
Benzyl alcohols formed by the reduction of benzaldehydes, alkyl aryl ketones, and benzophenones with sodium tetrahydridoborate in alcohols undergo in situ etherification with the solvent in the presence of a catalytic amount of HCl. Thus the process may be regarded as one-pot transformation of carbonyl compounds into the corresponding benzyl ethers. The yields of ethers depend on the substituent nature in the aromatic fragment of the initial carbonyl compound and on the alcohol used as reduction medium.
Cucurbit[7]uril promoting PdCl2-catalyzed cross-coupling reaction of benzyl halides and arylboronic acids in aqueous media
Zhao, Guangkuan,Wang, Zhen,Wang, Ruixin,Li, Jingya,Zou, Dapeng,Wu, Yangjie
supporting information, p. 5319 - 5322 (2015/01/16)
The research provides a novel approach for producing diarylmethane derivatives using CB[7]-NaCl-PdCl2catalyzed Suzuki cross-coupling reaction of benzyl chloride derivatives and arylboronic acids in ethanol aqueous solution.
Proton-exchanged montmorillonite-mediated reactions of methoxybenzyl esters and ethers
Chen, Dongyin,Xu, Chang,Deng, Jie,Jiang, Chunhuan,Wen, Xiaoan,Kong, Lingyi,Zhang, Ji,Sun, Hongbin
, p. 1975 - 1983 (2014/03/21)
Proton-exchanged montmorillonite (H-mont) was found to be an eco-friendly and cost-effective catalyst for the generation of O-methylated quinone methides (QM) from the corresponding p or o-methoxybenzyl esters and ethers. Nucleophilic trapping of the O-methylated QM with arenes, alcohols, 1,3-dicarbonyl compounds, silyl enol ethers, and allylsilanes has been carried out, respectively, leading to eco-friendly benzylation reactions. Using this protocol, H-mont-mediated deprotection of PMB-protected esters and ethers have been realized for the first time. This work would pave the way for further exploration in O-alkylated QM that are of chemical and biological significance.
A very practical and selective method for PMB protection of alcohols
Chavan, Subhash P.,Harale, Kishor R.
experimental part, p. 4683 - 4686 (2012/09/05)
A very simple, practical and efficient one-step heterogeneous protocol for the PMB protection of alcohols using Amberlyst-15 has been developed. The stability and hazard issues regarding PMBCl and PMBBr are totally avoided by directly using anisyl alcohol for the protection. Alcohols are protected in very good yields. The selective mono-PMB protection of diols as well as di-PMB protection of diols was achieved in good yields, along with the demonstration of recyclability of the catalyst.
Direct synthesis of unsymmetrical ethers from alcohols catalyzed by titanium cation-exchanged montmorillonite
Mitsudome, Takato,Matsuno, Tsuyoshi,Sueoka, Shoichiro,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
supporting information; experimental part, p. 610 - 613 (2012/04/23)
Titanium-exchanged montmorillonite (Ti4+-mont) was found to act as an efficient heterogeneous catalyst for the etherification of a wide range of alcohols under mild reaction conditions. Ti4+-mont was reusable with retention of high efficiency and applicable to scale-up reaction conditions. The Royal Society of Chemistry 2012.
New method for the synthesis of benzyl alkyl ethers mediated by FeSO 4
Joshi, Girdhar,Adimurthy, Subbarayappa
experimental part, p. 720 - 728 (2011/03/22)
The synthesis of benzyl alkyl ethers from benzyl bromides and alcohols using FeSO4 as a recoverable and reusable mediator has been described without use of base and cosolvent under mild conditions.
A novel, chemoselective and efficient microwave-assisted deprotection of silyl ethers with Selectfluor
Shah, Syed Tasadaque A.,Singh, Surendra,Guiry, Patrick J.
experimental part, p. 2179 - 2182 (2009/07/01)
A novel microwave-assisted, chemoselective and efficient method for the cleavage of silyl ethers (aliphatic and aromatic) catalyzed by Selectfluor is reported. A wide range of TBS-, TIPS-, and TBDPS-protected alkyl silyl ethers can be chemoselectively cleaved in high yield in the presence of aryl silyl ethers. The chemoselective deprotection of phenolic TBS ethers, and not the TIPS- or TBDPS-protected phenolic ethers, and the deprotection of silyl esters were also achieved under these reaction conditions. In addition, the transetherification and etherification of benzylic hydroxy groups in alcoholic solvents is observed.
