4203-44-5Relevant academic research and scientific papers
Bis(trifluoromethanesulfonimide) (BSI): Acidity and application to hydrofunctionalization as a Br?nsted acid catalyst
Takagi, Ryukichi,Sakai, Yuichiro,Duong, Duyen Thi
, (2021/03/23)
A binaphthyl derivative, bearing bis(trifluoromethanesulfonimide) (BSI) moiety, was developed as a novel Br?nsted acid. Computational prediction of the pKa value of BSI indicated its classification as a strong Br?nsted acid. BSI catalyzed the h
Aryl Boronic Acid Catalysed Dehydrative Substitution of Benzylic Alcohols for C?O Bond Formation
Estopi?á-Durán, Susana,Donnelly, Liam J.,Mclean, Euan B.,Hockin, Bryony M.,Slawin, Alexandra M. Z.,Taylor, James E.
supporting information, p. 3950 - 3956 (2019/02/16)
A combination of pentafluorophenylboronic acid and oxalic acid catalyses the dehydrative substitution of benzylic alcohols with a second alcohol to form new C?O bonds. This method has been applied to the intermolecular substitution of benzylic alcohols to form symmetrical ethers, intramolecular cyclisations of diols to form aryl-substituted tetrahydrofuran and tetrahydropyran derivatives, and intermolecular crossed-etherification reactions between two different alcohols. Mechanistic control experiments have identified a potential catalytic intermediate formed between the aryl boronic acid and oxalic acid.
Visible-Light-Induced C-O Bond Formation for the Construction of Five- and Six-Membered Cyclic Ethers and Lactones
Im, Honggu,Kang, Dahye,Choi, Soyeon,Shin, Sanghoon,Hong, Sungwoo
supporting information, p. 7437 - 7441 (2018/11/27)
Visible-light-induced intramolecular C-O bond formation was developed using 2,4,6-triphenylpyrylium tetrafluoroborate (TPT), which allows the regiocontrolled construction of cyclic ethers and lactones. The reaction is likely to proceed through the single-electron oxidation of the phenyl group, followed by the formation of a benzylic radical, thus preventing a competing 1,5-hydrogen abstraction pathway. Detailed mechanistic studies suggest that molecular oxygen is used to trap the radical intermediate to form benzyl alcohol, which undergoes cyclization. This new approach serves as a powerful platform by providing efficient access to valuable five- and six-membered cyclic ethers and lactones with a unified protocol.
Visible light-promoted ring-opening functionalization of unstrained cycloalkanols via inert C-C bond scission
Wang, Dongping,Mao, Jincheng,Zhu, Chen
, p. 5805 - 5809 (2018/07/13)
Described herein is a novel, useful, visible light-promoted ring-opening functionalization of unstrained cycloalkanols. Upon scission of an inert cyclic C-C σ-bond, a set of medium- and large-sized rings are readily brominated under mild reaction conditio
Indium Catalyzed Hydrofunctionalization of Styrene Derivatives Bearing a Hydroxy Group with Organosilicon Nucleophiles
Kita, Yuji,Yata, Tetsuji,Nishimoto, Yoshihiro,Yasuda, Makoto
, p. 740 - 753 (2018/01/28)
Hydrofunctionalization is one of the most important transformation reactions of alkenes. Herein, we describe the development of an indium-triiodide-catalyzed hydrofunctionalization of alkenes bearing a hydroxy group using various types of organosilicon nucleophiles. Indium triiodide was the most effective catalyst, whereas typical Lewis acids such as TiCl4, AlCl3, and BF3·OEt2 were ineffective. Many functional groups were successfully introduced, and these resulted in yields of 31-86%. Various styrene derivatives were also applicable to this reaction. Mechanistic investigation revealed that the present hydrofunctionalization proceeded through Br?nsted acid-catalyzed intramolecular hydroalkoxylation of alkenes followed by InI3-catalyzed substitution reaction of cyclic ether intermediates.
Cyclic ether synthesis from diols using trimethyl phosphate
Asai, Shota,Kato, Maho,Monguchi, Yasunari,Sajiki, Hironao,Sawama, Yoshinari
supporting information, p. 4787 - 4790 (2017/07/06)
Cyclic ethers have been effectively synthesized via the intramolecular cyclization of diols using trimethyl phosphate and NaH. The present cyclization could proceed at room temperature to produce 5-7 membered cyclic ethers in good to excellent yields. Substrates possessing a chiral secondary hydroxy group were transformed into the corresponding chiral cyclic ethers along with the retention of their stereochemistries.
Niobium-Catalyzed Intramolecular Addition of O-H and N-H Bonds to Alkenes: A Tool for Hydrofunctionalization
Ferrand, Laura,Tang, Yue,Aubert, Corinne,Fensterbank, Louis,Mouriès-Mansuy, Virginie,Petit, Marc,Amatore, Muriel
, p. 2062 - 2065 (2017/04/28)
A convenient, versatile, and easy to handle intramolecular hydrofunctionalization of alkenes (C-O and C-N bonds formation) is reported using a novel niobium-based catalytic system. This atom economic and eco-friendly methodology provides an additional synthetic tool for the straightforward formation of valuable building blocks enabling molecular complexity. Various pyran, furan, pyrrolidine, piperidine, lactone, and lactam derivatives as well as spirocyclic compounds are produced in high yields and selectivities.
Gallium-catalyzed reductive lactonization of γ-keto acids with a hydrosilane
Sakai, Norio,Horikawa, Shuhei,Ogiwara, Yohei
, p. 81763 - 81766 (2016/09/09)
Described herein is the GaCl3-catalyzed lactonization of γ-keto carboxylic acids in the presence of PhSiH3 leading to the direct preparation of γ-lactone derivatives. This reducing system showed a relatively wide functional group tolerance.
Toward Customized Tetrahydropyran Derivatives through Regioselective α-Lithiation and Functionalization of 2-Phenyltetrahydropyran
Cicco, Luciana,Addante, Valeria,Temperini, Andrea,Donau, Carsten Adam,Karaghiosoff, Konstantin,Perna, Filippo Maria,Capriati, Vito
, p. 3157 - 3161 (2016/07/19)
In this contribution, the first direct and efficient functionalization of the preformed 2-phenyltetrahydropyran (2-PhTHP) nucleus by electrophilic interception of the corresponding α-lithiated derivative by employing sBuLi as the base and THF as the solvent at –78 °C was explored. The presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA) proved to be critical to governing reaction feasibility both in polar and apolar solvents and for improving the yield of the reaction. Both carbon- and heteroatom-based halides were found to be competent electrophiles for this transformation, as well as aliphatic and aromatic aldehydes and ketones, isocyanates, and carboxylic acid derivatives. The combination of hexane/TMEDA lowered the rate of racemization of α-lithiated optically active 2-PhTHP, which thereby enabled calculation of its barrier to inversion at –78 °C.
Direct C-H bond activation of ethers and successive C-C bond formation with benzene by a bifunctional palladium-titania photocatalyst
Tyagi, Akanksha,Matsumoto, Tomoya,Kato, Tatsuhisa,Yoshida, Hisao
, p. 4577 - 4583 (2016/07/06)
Palladium-loaded titanium oxide was found to work as a bifunctional photocatalyst for functionalization of benzene with ether upon photoirradiation, without using any special reagents. The metal-loaded TiO2 photocatalyst activated a C-H bond of ethers and the heterogeneous Pd metal nanoparticle catalyst promoted the successive C-C bond formation between benzene and the radical species. In this reaction, benzene reacted very selectively with the α-carbon of various ethers at least in the initial stage of the reaction. Kinetic and ESR studies revealed a detailed mechanism for the reaction.
