4024-14-0Relevant articles and documents
Aromatic substituent effect on the stereoselectivity of the condensed- and gas-Phase Acid-Induced methanolysis in 2-Aryloxiranes derived from 3,4-dihydronaphthalene and trans-1,2,3,4,4a,10a-Hexahydrophenanthrene bearing a tertiary benzylic oxirane nucleophilic centre
Crotti, Paolo,Di Bussolo, Valeria,Favero, Lucilla,Pineschi, Mauro,Sergiampietri, Daniela,Renzi, Gabriele,Ricciutelli, Massimo,Roselli, Graziella
, p. 5515 - 5536 (1997)
The ring-opening reactions with MeOH of the title benzocondensed 2-aryl oxiranes 6 and 7a,b both in the condensed (methanolysis) and in the gas phase were examined, obtaining in all cases a good Hammett-type linear correlation. Results indicate that the secondary or tertiary nature of the benzylic oxirane carbon is not responsible for the different stereochemical behavior so far encountered in different 2-aryl oxirane systems under the same operating conditions.
Anodic oxidation triggered divergent 1,2- And 1,4-group transfer reactions of β-hydroxycarboxylic acids enabled by electrochemical regulation
Jiang, Yangye,Lu, Gang,Mo, Fanyang,Yang, Jianxin,Yang, Yang,Yin, Yunxing,Zeng, Chengchu,Zhang, Lei,Zhang, Xianhao,Zhang, Zhenxing
, p. 12021 - 12028 (2020/11/26)
We report a set of electrochemically regulated protocols for the divergent synthesis of ketones and β-keto esters from the same β-hydroxycarboxylic acid starting materials. Enabled by electrochemical control, the anodic oxidation of carboxylic acids proceeded in either a one-electron or a two-electron pathway, leading to a 1,4-aryl transfer or a semipinacol-type 1,2-group transfer product with excellent chemoselectivity. The 1,4-aryl transfer represents an unprecedented example of carbon-to-oxygen group transfer proceeding via a radical mechanism. In contrast to previously reported radical group transfer reactions, this 1,4-group transfer process features the migration of electron-rich aryl substituents. Furthermore, with these chemoselective electrochemical oxidation protocols, a range of ketones and β-keto esters including those possessing a challenging-to-access medium-sized ring could be synthesized in excellent yields. This journal is
Fluoride Anions in Self-Assembled Chiral Cage for the Enantioselective Protonation of Silyl Enol Ethers
Paladhi, Sushovan,Liu, Yidong,Kumar, B. Senthil,Jung, Min-Jung,Park, Sang Yeon,Yan, Hailong,Song, Choong Eui
supporting information, p. 3279 - 3282 (2017/06/23)
The potential of Song's chiral oligoethylene glycols (oligoEGs) as catalysts was explored in the enantioselective protonation of trimethylsilyl enol ethers in combination with alkali metal fluoride (KF and CsF) and in the presence of a proton source. Highly enantioselective protonations of various silyl enol ethers of α-substituted tetralones were achieved, producing chiral α-substituted tetralones in full conversion and with up to 99% ee. The established protocol was successfully extended to the synthesis of biologically relevant chiral α-substituted chromanone and thiochromanone derivatives.
Anti-Markovnikov Oxidation of β-Alkyl Styrenes with H2O as the Terminal Oxidant
Zhang, Guoting,Hu, Xia,Chiang, Chien-Wei,Yi, Hong,Pei, Pengkun,Singh, Atul K.,Lei, Aiwen
supporting information, p. 12037 - 12040 (2016/09/28)
Oxygenation of alkenes is one of the most straightforward routes for the construction of carbonyl compounds. Wacker oxidation provides a broadly useful strategy to convert the mineral oil into higher value-added carbonyl chemicals. However, the conventional Wacker chemistry remains problematic, such as the poor activity for internal alkenes, the lack of anti-Markovnikov regioselectivity, and the high cost and chemical waste resulted from noble metal catalysts and stoichiometric oxidant. Here, we describe an unprecedented dehydrogenative oxygenation of β-alkyl styrenes and their derivatives with water under external-oxidant-free conditions by utilizing the synergistic effect of photocatalysis and proton-reduction catalysis that can address these challenges. This dual catalytic system possesses the single anti-Markovnikov selectivity due to the property of the visible-light-induced alkene radical cation intermediate.
Oxone-acetone mediated Wacker-type oxidation of benzo-fused olefins
Phatake, Ravindra S.,Ramana, Chepuri V.
supporting information, p. 3868 - 3871 (2015/06/08)
Herein we disclose a novel application of the oxone-acetone combination for the Wacker-type oxidation of indenes and dihydronaphthalenes leading, respectively, to indan-2-ones and 2-tetralones. The amount of the base employed in the reaction seems to switch the reaction path from dioxygenation to Wacker-type oxidation. Control experiments suggest that the reaction is not proceeding via the epoxide route and also that there is no role of trace amounts of metals present in the reagents on the current oxidation.
Synthesis of 2-tetralone derivatives by Bi(OTf)3-catalyzed intramolecular hydroarylation/isomerization of propargyl alcohols
Yun, Jihee,Park, Jungmin,Kim, Jaehyun,Lee, Kooyeon
, p. 1045 - 1048 (2015/02/19)
Compared to 1-tetralones, 2-tetralones are expensive, less stable, and difficult to synthesize. A concise Bi-catalyzed method was developed for the synthesis of 2-tetralones from 5-phenylpent-1-yn-3-ol derivatives. Diverse 2-tetralones were obtained in moderate to good yields under mild conditions.
PREPARATION METHOD OF 2-TETRALONE DERIVATIVES CATALYZED BY BISMUTH/SILVER MIXED SALTS
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Paragraph 0063; 0064; 0065; 0066; 0067, (2016/10/17)
The present invention relates to a method for preparing a 2-tetralone derivative using a bismuth/silver mixed catalyst in a simple and efficient manner. According to the method, a target material can be obtained within short time as the bismuth/silver mixed catalyst is used. The 2-tetralone derivative, prepared by the method, can be used to synthesize pharmaceutical products and intermediates of natural materials. The 2-tetralone derivative is represented by Chemical formula 1.COPYRIGHT KIPO 2015
Oxidative rearrangement of alkenes using in situ generated hypervalent iodine(III)
Ahmad, Anees,Scarassati, Paulo,Jalalian, Nazli,Olofsson, Berit,Silva Jr., Luiz F.
supporting information, p. 5818 - 5820 (2013/10/01)
A novel protocol for the oxidative rearrangement of alkenes using in situ generated hypervalent iodine(III) was developed. This approach uses inexpensive, readily available, and stable chemicals (PhI, mCPBA, and TsOH) giving rearrangement products in yields comparable to those obtained using the more expensive commercially available [hydroxy(tosyloxy)iodo]benzene [HTIB or Koser's reagent]. Additionally, an alternative protocol for the synthesis of 1-methyl-2-tetralone through the one-step epoxidation/rearrangement of 4-methyl-1,2-dihydronaphthalene using mCPBA and TsOH was developed.
Ring contraction of 1,2-dihydronaphthalenes promoted by thallium(III) in acetonitrile: A diastereoselective approach to indanes
Ferraz, Helena M. C.,Carneiro, Vania M. T.,Silva Jr., Luiz F.
experimental part, p. 385 - 388 (2009/06/18)
Trans-1,3-Disubstituted indanes are conveniently accessed by a stereoselective ring contraction of 1,2-dihydronaphthalenes upon treatment with thallium(III) nitrate (TTN) in acetonitrile. Under these conditions, the oxidative rearrangement of either di- or trisubstituted double bonds is possible. Georg Thieme Verlag Stuttgart.
Cyclization and ring-expansion processes involving samarium diiodide promoted reductive formation and subsequent oxidative ring opening of cyclopropanol derivatives
Tsuchida, Hiroyuki,Tamura, Mutsuko,Hasegawa, Eietsu
supporting information; experimental part, p. 2467 - 2475 (2009/07/18)
Samarium diiodide promoted reaction of various α-bromornethyl cycloalkanones, followed by subsequent treatment with trimethylsilyl chloride, leads to the production of cyclopropyl silyl ethers embedded in bicyclo[m.l.0]alkane frameworks. Treatment of the ethers with oxidative electron-transfer reagents, such as Fe(III), Ce(IV), and Mn(III) salts, generates ring-expanded ketones that convert to cyclic conjugated enones in moderate to good yields. In addition, the reduction-oxidation reaction sequences can be successfully performed in one pot. The regioselectivities of cyclopropane ring opening in the bicyclic substrates depend on the oxidizing agents used. For example, reactions promoted by FeCl3 with pyridine lead to the expected ring-expansion process involving internal-bond cleavage of bicycloalkane and yielding cyclic enones as final products. In contrast, reactions with Ce(NH4)I(NO3)6 or Mn(OAc) 3 as oxidizing agents proceed by way of external-bond cleavage to give α-iodomethyl cycloalkanones.
