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4890-85-1Relevant academic research and scientific papers
Regenerative role of the red phosphorus in the couple 'HIaq/Pred'
Albouy, Dominique,Etemad-Moghadam, Guita,Vinatoru, Mircea,Koenig, Max
, p. 295 - 299 (1997)
The synthesis of ortho-substituted benzoic acid 3 from benzalphthalide 1 in the presence of 'hydriodic acid-red phosphorus' (HIaq/Pred) occurs via the formation of benzylphthalide 2 as reaction intermediate. Its preparation is optimized by use of the 'supported reaction in dry media' process (Silica/HIaq) under microwave irradiation for 8 min. The role of the red phosphorus in the reduction reaction is elucidated: it intervenes in a catalytic cycle by an oxido-reductive disproportionation with the liberated iodine, affording either hypophosphorous acid in aqueous media, or P2I4 in anhydrous media with concomitant regeneration of HI. Thus, the presence of Pred in the couple 'HIaq/Pred' allows recycling of the hydriodic acid and enhances its reducing efficiency.
Enantioselective Remote C(sp3)-H Cyanation via Dual Photoredox and Copper Catalysis
Chen, Hui,Jin, Weiwei,Yu, Shouyun
, p. 5910 - 5914 (2020/08/12)
The remote C(sp3)-H cyanation of carboxamides has been described by merging photoredox and copper catalysis in a site-selective and enantiocontrolled manner. The protocol is the integration of photoinduced and nitrogen-centered radical-mediated intermolecular hydrogen atom transfer with chiral copper-complex-catalyzed radical cyanation. This strategy gives enantio-enriched cyanated amides in high yields.
Cooperative iodine and photoredox catalysis for direct oxidative lactonization of carboxylic acids
Duhamel, Thomas,Mu?iz, Kilian
, p. 933 - 936 (2019/01/23)
A new method for the formation of γ- and δ-lactones from carboxylic acids through direct conversion of benzylic C-H to C-O bonds is described. The reaction is conveniently induced by visible light and relies on a mild cooperative catalysis by the combination of molecular iodine and an organic dye.
Synthesis method of psychotropic drug-amitriptyline intermediate compound
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Paragraph 0069-0072; 0076; 0077; 0082; 0087, (2018/07/30)
The invention relates to a synthesis method of a psychotropic drug-amitriptyline intermediate compound, i.e., a compound 2-(2-phenylethyl)benzoic acid shown in a formula (III), and the formula (III) is described in the description. The synthesis method concretely comprises the following steps: enabling a compound shown in a formula (I) to react with a compound shown in a formula (II) in a bicomponent organic solvent at the temperature of 70-100 DEG C in presence of a catalyst, a nitrogen polydentate ligand, an oxidant and organic alkali, and carrying out aftertreatment after the reaction is finished so as to obtain the compound shown in the formula (III), wherein the formula (I) and the formula (II) are described in the description, X is halogen, Y is alkali-metal element, and R is H or analkyl group having 1-6 carbon atoms. After the method is adopted, a high yield and high purity target product can be obtained by means of a specific comprehensive reaction system, so that a novel route is provided for the synthesis of the amitriptyline intermediate; the synthesis method has good research value and industrialization amplification potential.
Preparation method of carboxylic acid compound
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Paragraph 0113; 0211-0213, (2017/08/29)
The invention provides a preparation method of a carboxylic acid compound. The preparation method comprises the following step of taking a lactone component to react with hydrogen in the presence of a compound catalyst to obtain the carboxylic acid compound. The compound catalyst comprises a hydrogenation catalyst and Lewis acid. In the presence of the compound catalyst comprising the hydrogenation catalyst and the Lewis acid, the lactone component is subjected to hydrogenation ring-opening reaction to obtain the carboxylic acid compound. The preparation method has the advantages of moderate reaction conditions and high yield; compared with a traditional method, less byproducts are generated, green and chemical requirements are met and the industrial value is better.
A Comprehensive Study on Metal Triflate-Promoted Hydrogenolysis of Lactones to Carboxylic Acids: From Synthetic and Mechanistic Perspectives
Zhu, Rui,Jiang, Ju-Long,Li, Xing-Long,Deng, Jin,Fu, Yao
, p. 7520 - 7528 (2017/11/10)
Direct hydrogenolysis of lactone to carboxylic acid (i.e., hydrogenolysis of the Calkoxy-O bond with the carbonyl group untouched) is generally difficult, as the current strategies employing Br?nsted acids as the catalyst usually require harsh conditions such as a high temperature and a high H2 pressure. Herein, we report a developed solvent-free catalytic transformation, in which W(OTf)6 is believed to promote the hydrogenolysis process. This strategy could efficiently hydrogenate lactones to carboxylic acids under extra mild conditions (e.g., a reaction temperature of 2) and showed a broad substrate scope. In addition, the catalytic protocol can be further applied to the hydrogenolysis of polyhydroxyalkanoate, as a renewable polymer, to the corresponding straight-chain carboxylic acids. An extensive mechanistic study was subsequently performed, and the density functional theory calculations revealed a reaction pattern, including the complete cleavage of the C=O bond with the assistance of the W(OTf)6 catalyst. Moreover, the key intermediate created in the mechanism, as an oxonium with an OTf moiety, was successfully detected by electrospray ionization mass spectra. Through a comparison with the Br?nsted acid-catalyzed system, the study confirmed that the existence of the OTf moiety can significantly lower the barriers associated with the rearrangement and elimination processes. Meanwhile, emphasis was placed on the critical role that the anion plays, as well as the fact that the anion effect is directly related to the chemoselectivity.
Guanidine catalyzed aerobic reduction: A selective aerobic hydrogenation of olefins using aqueous hydrazine
Lamani, Manjunath,Guralamata, Ravikumara Siddappa,Prabhu, Kandikere Ramaiah
supporting information; experimental part, p. 6583 - 6585 (2012/07/14)
An efficient aerobic reduction of olefins, internal as well as terminal, is developed using guanidine as an organocatalyst. A remarkable chemoselectivity in reduction has been demonstrated in the presence of a variety of functional groups and protective groups and a selective reduction of a terminal olefin in the presence of an internal olefin is revealed.
Electrophilic aromatic substitution of arenes with CO2 mediated by R3SiB(C6F5)4
Konno, Megumi,Chiba, Masafumi,Nemoto, Koji,Hattori, Tetsutaro
, p. 913 - 914,2 (2020/08/31)
The FriedelCrafts- type carboxylation of arenes has been achieved by activating CO2 with silylium borates. The reaction exhibits broader substrate applicability than does our previously reported AlX3/R 3SiX-mediated carboxylation.
Raney nickel-catalyzed hydrogenation of unsaturated carboxylic acids with sodium borohydride in water
Rao, Gopal Krishna,Gowda, Narendra B.,Ramakrishna, Ramesha A.
experimental part, p. 893 - 904 (2012/02/01)
A mild, selective, and green method for the reduction of unsaturated carboxylic acids with sodium borohydride-Raney nickel (W6) system in water is reported. This method is practical and safe and avoids use of organic solvents. Taylor & Francis Group, LLC.
Iron(III) chloride-catalysed aerobic reduction of olefins using aqueous hydrazine at ambient temperature
Lamani, Manjunath,Ravikumara, Guralamata S.,Prabhu, Kandikere Ramaiah
supporting information; experimental part, p. 1437 - 1442 (2012/07/03)
A chemoselective reduction of olefins and acetylenes is demonstrated by employing catalytic amounts of ferric chloride hexahydrate (FeCl 3·6 H2O) and aqueous hydrazine (NH 2NH2·H2O) as hydrogen source at room temperature. The reduction is chemoselective and tolerates a variety of reducible functional groups. Unlike other metal-catalysed reduction methods, the present method employs a minimum amount of aqueous hydrazine (1.5-2 equiv.). Also, the scope of this method is demonstrated in the synthesis of ibuprofen in aqueous medium. Copyright
