- Benzyl C–O and C–N Bond Construction via C–C Bond Dissociation of Oxime Ester under Visible Light Irradiation
-
A photoredox benzyl activation was developed via formidable C(sp3)–C(sp3) bond dissociation of 1-aryl acetone oxime esters, which were easily prepared from benzyl ketones. Further coupling with O- and N- nucleophiles successfully forged important benzyl ether and amines derivatives in one pot. In this process, different substitutions on oxime esters were found compatible and various primary and secondary alcohols and amines, as well as amides showed good performance as nucleophiles. Mechanistic studies by control experiments, electrochemical measurements and in-situ NMR spectra proposed a N–O bond interruption/C–C bond fragmentation/oxidation sequence to provide the key cation intermediate for the next electrophilic SN process. The features of mild condition, short reaction time and broad substrate scope made this new strategy much promising in the transformation of benzyl compounds, which might be valuable in last-stage functionalizations.
- Fan, Xiuwei,Lei, Tao,Liu, Zan,Yang, Xiu-Long,Cheng, Yuan-Yuan,Liang, Ge,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
-
p. 1551 - 1558
(2019/09/09)
-
- SYNTHESIS OF HYPERVALENT IODINE REAGENTS WITH DIOXYGEN
-
Methods of synthesis of hypervalent iodine reagents and methods for oxidation of organic compounds are disclosed.
- -
-
Paragraph 0114-0117; 0138-0139
(2019/01/15)
-
- Catalytic Alkyne Arylation Using Traceless Directing Groups
-
By using Pd0/Mandyphos, we achieved a three-component aminoarylation of alkynes to generate enamines, which are then hydrolyzed to either α-arylphenones or α,α-diarylketones. This Pd-catalyzed method overcomes established known pathways to enable the use of amines as traceless directing groups for C?C bond formation.
- Park, Jung-Woo,Kang, Bubwoong,Dong, Vy M.
-
p. 13598 - 13602
(2018/09/25)
-
- Oxidation Catalysis by an Aerobically Generated Dess–Martin Periodinane Analogue
-
Hypervalent iodine(V) reagents, such as Dess–Martin periodinane (DMP) and 2-iodoxybenzoic acid (IBX), are broadly useful oxidants in chemical synthesis. Development of strategies to generate these reagents from dioxygen (O2) would immediately enable use of O2 as a terminal oxidant in a broad array of substrate oxidation reactions. Recently we disclosed the aerobic synthesis of I(III) reagents by intercepting reactive oxidants generated during aldehyde autoxidation. In this work, aerobic oxidation of iodobenzenes is coupled with disproportionation of the initially generated I(III) compounds to generate I(V) reagents. The aerobically generated I(V) reagents exhibit substrate oxidation chemistry analogous to that of DMP. The developed aerobic generation of I(V) has enabled the first application of I(V) intermediates in aerobic oxidation catalysis.
- Maity, Asim,Hyun, Sung-Min,Wortman, Alan K.,Powers, David C.
-
supporting information
p. 7205 - 7209
(2018/05/29)
-
- Rhenium complex-catalyzed Meinwald rearrangement reactions of oxiranes
-
The Meinwald rearrangement reaction of oxiranes to the corresponding carbonyl compounds is efficiently catalyzed by the ReBr(CO)5 complex.
- Umeda, Rui,Muraki, Masahito,Nakamura, Yuudai,Tanaka, Tomoyuki,Kamiguchi, Kyohei,Nishiyama, Yutaka
-
supporting information
p. 2393 - 2395
(2017/05/29)
-
- Synthesis of 1,3-Cycloalkadienes from Cycloalkenes: Unprecedented Reactivity of Oxoammonium Salts
-
Few methods allow for the direct conversion of cycloalkenes into cycloalkadienes with high chemo- and regioselectivity. Herein, we report a convenient one-pot process for this transformation that involves the unprecedented N-preferential group transfer of N-oxoammonium salts to cycloalkenes, followed by Cope elimination, to afford cycloalkadienes at room temperature and pressure.
- Nagasawa, Shota,Sasano, Yusuke,Iwabuchi, Yoshiharu
-
supporting information
p. 13189 - 13194
(2016/10/30)
-
- 4-CH3CONH-TEMPO/Peracetic Acid System for a Shortened Electron-Transfer-Cycle-Controlled Oxidation of Secondary Alcohols
-
We have developed a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) derivative catalyzed oxidation of secondary alcohols with peracetic acid as the oxidant, which was generated from H2O2 and acetic acid catalyzed by strongly acidic resins. The oxidation of alcohols proceeded well through a shortened electron-transfer cycle under metal-free conditions, avoiding the use of any other electron-transfer mediators such as halides. In addition, we demonstrated that the present system exhibited excellent efficiency under mild conditions for the oxidation of aromatic, aliphatic, and allylic secondary alcohols. Shortcut to ketones: The 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-derivative-catalyzed oxidation of secondary alcohols employing peracetic acid generated from H2O2 and acetic acid with strongly acidic resins proceeds through a shortened electron-transfer cycle without halide additives. The system not only exhibits excellent efficiency at room temperature but also has a wide substrate scope.
- Zhang, Shufang,Miao, Chengxia,Xia, Chungu,Sun, Wei
-
p. 1865 - 1870
(2015/06/23)
-
- AZA-PYRIDONE COMPOUNDS AND USES THEREOF
-
Disclosed herein are aza-pyridone compounds, pharmaceutical compositions that include one or more aza-pyridone compounds, and methods of synthesizing the same. Also disclosed herein are methods of ameliorating and/or treating a disease and/or a condition, including an orthomyxovirus infection, with an aza-pyridone compounds. Examples of an orthomyxovirus viral infection include an influenza infection.
- -
-
Paragraph 0165; 0166
(2015/03/16)
-
- PROCESS FOR CREATING CARBON-CARBON BONDS USING CARBONYL COMPOUNDS
-
The present invention concerns a process for preparing a compound of formula (I) by reaction between a compound of formula (II) and a compound of formula (III) in the presence of a copper-containing catalyst, a ligand and base. The invention also concerns the implementing of this process for the preparation of building blocks to prepare molecules of interest in particular in the pharmaceutical, agro-chemical fields, etc.
- -
-
Paragraph 0426-0427
(2015/06/24)
-
- Enantioselective oxidation of racemic secondary alcohols catalyzed by chiral Mn(iii)-salen complexes with N-bromosuccinimide as a powerful oxidant
-
We demonstrate an efficient enantioselective oxidation of secondary alcohols catalyzed by Mn(iii)-salen complex using N-bromosuccinimide (NBS) as the oxidant. The new protocol is very efficient for the oxidative kinetic resolution of a variety of secondary alcohols, including ortho-substituted benzylic alcohols. The Royal Society of Chemistry 2012.
- Xu, Daqian,Wang, Shoufeng,Shen, Zhiqiang,Xia, Chungu,Sun, Wei
-
supporting information
p. 2730 - 2732
(2012/11/07)
-
- Oxidative kinetic resolution of racemic secondary alcohols in water with chiral PNNP/Ir catalyst
-
Using water as solvent, the oxidative kinetic resolution of a wide range of racemic secondary alcohols with a chiral PNNP/Ir catalyst was investigated. The catalytic reaction proceeded smoothly with excellent enantioselectivity (up to 97% ee) under mild conditions, providing an environmentally benign process to achieve optically active alcohols.
- Zhang, Juanni,Yang, Xiangren,Zhou, Han,Li, Yanyun,Dong, Zhenrong,Gao, Jingxing
-
supporting information; experimental part
p. 1289 - 1292
(2012/06/18)
-
- Titanocene-promoted eliminations on epoxy alcohols and epoxy esters
-
The reaction of a series of 2,3-epoxy alcohols and the corresponding formates, acetates, and benzoates promoted by Cp2TiCl has been studied. The different outcome of the reaction of epoxy derivatives has been rationalized in terms of mechanistically biased processes. After homolytic oxirane cleavage, four main types of reaction were found: dehydroxylation, decarboxylation, dehydrogenation, and deoxygenation. The reaction products varied according to the substitution pattern. The radical nature of these eliminations is demonstrated.
- Fernandez-Mateos, Alfonso,Madrazo, Soledad Encinas,Teijon, Pablo Herrero,Gonzalez, Rosa Rubio
-
experimental part
p. 856 - 861
(2010/04/05)
-
- Pd-catalyzed α-arylation of trimethylsilyl enol ethers with aryl bromides and chlorides: A synergistic effect of two metal fluorides as additives
-
(Chemical Equation Presented) The long-sought-after palladium-catalyzed coupling of silyl enol ethers, both cyclic and acyclic, with a wide range of aryl bromides and chlorides to form α-aryl ketones is realized. The key to effective activation of the silicon enolate was the use of two metal fluoride additives, which operate in a synergistic fashion.
- Su, Weiping,Raders, Steven,Verkade, John G.,Liao, Xuebin,Hartwig, John F.
-
p. 5852 - 5855
(2007/10/03)
-
- GaCl3-catalyzed skeletal rearrangement of α,α, α-trisubstituted aldehydes
-
(Chemical Equation Presented) GaCl3 is found to be a superior catalyst for the skeletal rearrangement of α,α,α- trisubstituted aldehydes to ketones. The rearrangement can proceed smoothly in the presence of a catalytic amount of GaCl3, and even substrates having no heteroatoms α to the carbonyl group or without steric strains can be used. Double activation of a carbonyl group by two molecules of GaCl 3 was supported on the basis of experimental data and a DFT study.
- Oshita, Masayuki,Okazaki, Takao,Ohe, Kouichi,Chatani, Naoto
-
p. 331 - 334
(2007/10/03)
-
- Insight into the mechanism of oxidative kinetic resolution of racemic secondary alcohols by using manganese(III)(salen) complexes as catalysts
-
The oxidative kinetic resolution of various racemic secondary alcohols with PhI(OAc)2 catalyzed by chiral [MnIII(salen)] complexes in the presence of KBr was studied in a water/organic solvent mixture. The dramatic, synergetic effect of additives, organic solvent, and the substituents of chiral salen ligands on the enantioselectivities of the reactions is reported. Results from UV/Vis spectroscopy and ESI-MS studies provide evidence that these reactions are induced by the formation of a high-valent manganese intermediate.
- Li, Zhen,Tang, Zhong H.,Hu, Xiao X.,Xia, Chun G.
-
p. 1210 - 1216
(2007/10/03)
-
- Zeolite-Promoted Oxidations of 1,1-Diarylethylenes
-
(Equation Presented) The intrazeolite photooxygenations of four diarylethylenes have been examined. Several intermediates, including an epoxide, have been identified by comparison to independently synthesized samples. Aldehyde intermediates were shown to undergo intrazeolite Norrish type I cleavages in competition with a novel new photooxygenation/autoxidation reaction.
- Clennan, Edward L.,Pan, Gui-Ian
-
p. 4979 - 4982
(2007/10/03)
-
- Palladium-catalyzed aerobic oxidative kinetic resolution of alcohols with an achiral exogenous base
-
Substitution of exogenous (-)-sparteine for a more practical achiral base in the aerobic oxidative kinetic resolution of secondary alcohols is described. Carbonate bases are the most effective of those screened and allow for effective kinetic resolution of benzylic, allylic, and aliphatic substrates. The procedure was also successfully extended to the oxidative desymmetrization of meso diols.
- Mandal, Sunil K.,Sigman, Matthew S.
-
p. 7535 - 7537
(2007/10/03)
-
- Scope of enantioselective Palladium(II)-catalyzed aerobic alcohol oxidations with (-)-sparteine
-
Evaluation of the substrate scope for Pd(II)/ (-)-sparteine catalyzed aerobic oxidative kinetic resolution of secondary alcohols is disclosed. An improved system is found with use of tert-butyl alcohol solvent in which benzylic and aliphatic alcohols as well as alcohols containing olefins are effectively oxidatively resolved. For substrates that successfully undergo oxidative kinetic resolution, krel values are generally between 10 and 20. Successful scale-up of various substrates to 10-mmol scale is described. Extension to oxidative desymmetrization of 1,3-meso-diols is successful with enantiomeric excesses ranging from 78 to 85%.
- Mandal, Sunil K.,Jensen, David R.,Pugsley, Jacob S.,Sigman, Matthew S.
-
p. 4600 - 4603
(2007/10/03)
-
- Facile one-pot procedure for Et3Al-promoted asymmetric pinacol-type rearrangement
-
A facile procedure for the synthesis of enantiomerically pure α-substituted ketones is described. The pinacol-type 1,2-shift of sec-tert 1,2-diols could be effected by performing the following two processes in a one pot procedure, (1) regioselective methanesulfonylation, and (2) direct treatment of the resulting mesylate with Et3Al. This procedure allowed 1,2-shift reactions of various groups, including vinyl, aryl, and heteroaromatic groups, giving enantiomerically pure ketones in high yields.
- Shionhara, Tomoichi,Suzuki, Keisuke
-
p. 141 - 146
(2007/10/03)
-
- Aza-pinacol rearrangement: Acid-catalyzed rearrangement of aziridines to imines
-
A series of di-, tri-, and tetra-substituted N-tosylaziridines [N-(toluene-p-sulfonyl)aziridines] 1, prepared by aziridination of the corresponding alkenes with N-[(tolyl-p-sulfonyl)-imino]phenyliodinane (TsN = IPh), was found to undergo a BF3-catalyzed rearrangement (aza-pinacol rearrangement) under mild conditions to give the corresponding N-tosylimines 2 generally in satisfactory yields.
- Sugihara, Yoshiaki,Iimura, Shinya,Nakayama, Juzo
-
p. 134 - 135
(2007/10/03)
-
- Activation conditions play a key role in the activity of zeolite CaY: NMR and product studies of Bronsted acidity
-
CaY, activated under different conditions, was characterized with 1H, 31P, and 1H/27A] double resonance MAS NMR. The 1H MAS NMR spectra of CaY, calcined in an oven at 500 °C, shows resonances from H2O (bound to Ca2+ and the zeolite framework), CaOH+, aluminum hydroxides, silanols, and Bronsted acid sites. No evidence for Lewis acidity is observed on adsorption of trimethylphosphine, and an estimate of ≈16 Bronsted acid sites per unit cell is obtained for this sample. CaY activated in an oven at higher temperatures contains less water, but all the other species are still present. In contrast, CaY activated by slow ramping of the temperature under vacuum to 500 or 600 °C shows a much lower concentration of Bronsted acid sites (1/unit cell). Again, no evidence for Lewis acidity was observed. These NMR results have been utilized to understand the very different product distributions that are observed for reactions of 1,1- and 1,2-diarylethylenes in zeolite CaY activated in an oven (in air) and under vacuum. Samples with high concentrations of Bronsted acid sites react stoichiometrically with these sites, yielding diarylalkanes. At low concentrations, the Bronsted acid sites can act catalytically resulting in isomerization reactions.
- Kao, Hsien-Ming,Grey, Clare P.,Pitchumani, Kasi,Lakshminarasimhan,Ramamurthy
-
p. 5627 - 5638
(2007/10/03)
-
- Electrooxidative pinacol-type rearrangement of β-hydroxy sulfides. Efficient C-S cleavage mediated by chloride ion oxidation
-
Electrooxidation of α-phenyl substituted β-hydroxy sulfides in dichloromethane in the presence of chloride ions as the electrolyte results in a novel pinacol-type rearrangement to give 2-phenyl substituted ketones like 2-phenylcycloalkanone as the ring expansion product. The rearrangement is induced by an electrogenerated chloronium ion, which effects, instead of common C-C scission, a selective C-S cleavage of β-hydroxy sulfides.
- Kimura, Makoto,Kobayashi, Kazutaka,Yamamoto, Yasushi,Sawaki, Yasuhiko
-
p. 4303 - 4310
(2007/10/03)
-
- Inhibitors of acyl-CoA:cholesterol acyltransferase. 5. Identification and structure-activity relationships of novel β-ketoamides as hypocholesterolemic agents
-
A study of structure-activity relationships of substituted β-ketoamide ACAT inhibitors I and II was performed. The results of this study suggest that whereas the β-keto group was tolerated with no loss in activity, β- hydroxy and oxime moieties led to significantly reduced activity in vitro and in vivo. The most potent inhibitor from the acyclic series (I) (11, IC50 = 0.006 μM) contained a C-13 alkyl chain. This compound reduced plasma total cholesterol by 38% and 66% at 3 and 30 mg/kg, respectively, in cholesterol- fed rats. Dimethylation α to the anilide core (5) and subsequent N- methylation of the amide NH (6) decreased in vitro potency significantly. It was also found that high potency was retained with inhibitors which incorporated the carbonyl into a lactam ring (II).
- Augelli-Szafran,Blankley,Roth,Trivedi,Bousley,Essenburg,Hamelehle,Krause,Stanfield
-
p. 2943 - 2949
(2007/10/02)
-
- ORGANIC SYNTHESIS USING ORGANOSULFUR-NITRITES AND -NITRATES
-
Thionitrites or thionitrates have been considered to be unstable.However, bulky groups' thio-NOn such as t-butylthio-nitrites and -nitrates have been readily synthesized and found to be stable enough for the use of the useful organic syntheses as an excellent nitrosation and diazotization reagents under mild conditions.Direct conversion of amines to the corresponding halides in the presence of copper halides (II), fluorination of heterocyclic amines in the presence of sodium tetrafluoroborate, α- oximation of methylene groups in ketones, facile cleavage of C=N bond to ketones, and desulfurization of thioacetals and thioketals, and other useful organic syntheses are described.
- Kim, Yong Hae
-
p. 249 - 260
(2007/10/02)
-
- Low-valent titanium induced reductive coupling reaction of carboxylic derivatives with aromatic ketones
-
The intermolecular and intramolecular coupling reaction of carboxylic derivaties with aromatic ketones induced by titanium tetrachloride and zinc powder was studied.
- Shi, Da-Qing,Chen, Jian-Xie,Chai, Wen-Ying,Chen, Wei-Xing,Kao, Tsi-Yu
-
p. 2963 - 2964
(2007/10/02)
-
- Differences in Reactivity of Stabilized Carbanions with Haloarenes in the Initiation and Propagation Steps of the SRN1 Mechanism in DMSO
-
The photostimulated reaction of acetone (2), acetophenone (5), and anthrone (8) enolate ions with iodobenzene (1) in DMSO gave good yields of substitution products by the SRN1 mechanism.On the contrary, the monoanions of acetylacetone, diethyl malonate, and nitromethane (10) did not react under irradiation.However, the photostimulated reaction of 1 with 10 in the presence of 2 or pinacolone enolate ions gave 1-phenyl-2-nitroethane as a substitution product.The formation of this product can be explained if one assumes that the radical anion formed in the coupling reaction of phenyl radical with 10 fragments to give benzyl radical and nitrite ion.Benzyl radical then couples with 10 to give ultimately the observed product.From competition experiments the relative reactivity determined for the coupling reaction of different anions with phenyl radicals in the propagation cycle of the SRN1 mechanism is as follows: monoanion of β dicarbonyl compounds (unreactive) a (HOMO energy) of the anions and on the change in the ? energy that takes place in the coupling reaction.With reference to the initiation step (electron transfer from the carbanion to 1), the reactivity increases as the pKa of the conjugated acid of the nucleophile increases.
- Borosky, Gabriela L.,Pierini, Adriana B.,Rossi, Roberto A.
-
p. 247 - 252
(2007/10/02)
-
- Titanium(III) Chloride Mediated Reduction of 1-Nitro-2-phenylethenes
-
The reaction of 1-nitro-2-phenylethenes (β-nitrostyrenes) with aqueous titanium(III) chloride afforded substituted pyrroles in addition to the expected reduction products, oximes and carbonyl compounds. 2-Substituted 1-nitro-2-phenylethenes yielded divinylamine derivatives instead of pyrroles.The reaction mechanism has been rationalized by taking account of the electron transfer from titanium(III) species to the nitro olefines, followed by protonation, dimerization, cyclization, and/or hydrolysis.
- Sera, Akira,Fukumoto, Shoji,Tamura, Masako,Takabatake, Kiyoshi,Yamada, Hiroaki,Itoh, Kuniaki
-
p. 1787 - 1791
(2007/10/02)
-
- A Synthesis of Diphenylmethyl Ketones
-
The anion derived from diphenylmethane (2 eq.) reacts with carboxylic esters and anhydrides (1 eq.) to form diphenylmethyl ketones in 55-75percent purified yields.The procedure is one-step and permits the introduction of functionality incompatible with conditions used in earlier syntheses.
- Bunce, Richard A.,Dowdy, Eric D.
-
p. 3007 - 3014
(2007/10/02)
-
- Reactions of O,O-Diprotonated Nitro Olefins with Benzenes. Formations of Phenylacetones, 4H-1,2-Benzoxazines and Biarylacetone Oximes
-
O,O-Diprotonated nitro olefins undergo three alternative electrophilic reactions which yield α-phenylacetones, 4H-1,2-benzoxazines and biphenylacetone oximes depending on the reaction conditions (temperature and time) and aromatic substrates.Although these reactions are seemingly divergent, a common intermediate of a phenylated protonated aci-nitro species, derived from the dication, is postulated to be involved in the reactions.Furthermore, the formation of benzoxazines and biphenylacetone oximes can be interpreted in terms of participation of novel chemical species with phenylethylene dication character derived from the common intermediate.
- Ohwada, Tomohiko,Okabe, Kazuaki,Ohta, Toshiharu,Shudo, Koichi
-
p. 7539 - 7555
(2007/10/02)
-
- Novel Electrophilic Species Equivalent to α-Keto Cations. Reactions of O,O-Diprotonated Nitro Olefins with Benzenes Yield Arylmethyl Ketones
-
The N,N-dihydroxyiminium carbenium ions formed by O,O-diprotonation of nitro olefins in a strong acid, trifluoromethanesulfonic acid (TFSA), are discrete and novel dipositively charged species.The dications formed from α-substitited nitroethylenes are reactive electrophiles to give α-arylated ketones in high yields.This constitutes a versatile synthetic method for the preparation of α-arylated ketones, which are difficult to synthesize by the conventional Friedel-Crafts reactions.
- Okabe, Kazuaki,Ohwada, Tomohiko,Ohta, Toshiharu,Shudo, Koichi
-
p. 733 - 734
(2007/10/02)
-
- Synthesis and structures of titanaoxacyclobutanes
-
Titanaoxacyclobutanes can be prepared by the addition of a ketene to a titanium methylene complex or by the addition of a methylene fragment to a titanium ketene complex. For example, the addition of 2 equiv of dimethylsulfoxonium methylide to titanocene chloro-acyl complexes yields titanaoxacyclobutanes. The first equivalent deprotonates the acyl to form the titanocene ketene complex which is trapped by the second equivalent of the methylide to yield the metallaoxacyclobutane. Both routes yield complexes that are stable to temperatures above 60°C. Variable-temperature NMR studies show that the metallaoxacyclobutane ring is puckered with a barrier to inversion of 13-19 kcal/mol.
- Ho, Suzzy C.,Hentges,Grubbs, Robert H.
-
p. 780 - 782
(2008/10/08)
-
- Ytterbium Metal-promoted Novel Cross-coupling Reaction between Diaryl Ketones and Electrophiles
-
In the presence of Yb metal, diaryl ketones react nucleophilically with octan-2-one, acetonitrile, epoxides, and CO2 to give the corresponding unsymmetrical pinacols, α-hydroxy ketones, 1,3-diols, and α-hydroxy carboxylic acids, respectively.
- Hou, Zhaomin,Takamine, Kan,Aoki, Osamu,Shiraishi, Hiroyuki,Fujiwara, Yuzo,Taniguchi, Hiroshi
-
p. 668 - 670
(2007/10/02)
-
- Nucleophilic Addition of Lanthanoid Metal Umpoled Diaryl Ketones to Electrophiles
-
Ytterbium metal promoted cross-coupling reactions of diaryl ketones with a variety of electrophiles are described.Diaryl ketones treated with 1-2 equiv of Yb metal react smoothly with other ketones, nitriles, epoxides, CO2, etc., to give the corresponding unsymmetrical pinacols, α-hydroxy ketones, 1,3-diols, α-hydroxy carboxylic acids, etc., in good yields respectively.These reactions occur via nucleophilic addition of the intermediates 4a-c to electrophiles.Reaction of benzophenone (1a) with Yb metal is discussed in detail and some information on the composition of the intermediates of the reaction of diaryl ketones with Yb metal are also given.
- Hou, Zhaomin,Takamine, Kan,Aoki, Osamu,Shiraishi, Hiroyuki,Fujiwara, Yuzo,Taniguchi, Hiroshi
-
p. 6077 - 6084
(2007/10/02)
-
- CONTROL OF THE REACTIONS OF ORGANOMAGNESIUM COMPOUNDS. I. CONTROL OF THE REACTIONS OF ESTERS OF α-HYDROXY ACIDS WITH ARYLMAGNESIUM BROMIDES
-
The reaction of the esters of α-hydroxy acids with arylmagnesium bromides, which usually lead to the formation of bromomagnesium glycolates, can be directed toward the formation of ketones by chemical and thermal control
- Lapkin, I. I.,Kolbina, N. M.,Tatarenko, O. I.
-
p. 279 - 281
(2007/10/02)
-
- REACTION OF α,β-UNSATURATED ALDEHYDES WITH HYDROGEN PEROXIDE CATALYSED BY BENZENESELENINIC ACIDS AND THEIR PRECURSORS
-
Oxidation of α,β-unsaturated aldehydes with hydrogen perixide catalysed by benzeneselenic acids and their precursors has been investigated.Bis 2-nitrophenyl diselenide has proved to be the most effective catalyst.The major products resulting from the oxidation are vinyl formates (a) which on hydrolysis give saturated aldehydes or ketones (g) having the carbon chain shortened by one carbon atom, compared with the starting aldehydes.The minor products are formyloxyoxiranes (b), α-hydroxycarbonyl (e) and α-formyloxycarbonyl (f) compounds with the carbon chain shortened by one carbon atom.Carbonyl compounds d, formally derived from an oxidative fission of the carbon-carbon double bond, have been also isolated.Diformyloxy (4c) and formyloxyacetoxy phenylmethane (5c) have been isolated when cinnamaldehyde (4) or 1-phenyl-2-formyloxypropane (5a) were oxidized, respectively.Possible mechanisms of formation of these products are discussed.Similar products resulted when α,β-unsaturated aldehydes were oxidized with organic peroxy acids.
- Syper, Ludwik
-
p. 2853 - 2872
(2007/10/02)
-
- Direct Conversion of Oximes and Hydrazones into Their Ketones with Dinitrogen Tetroxide
-
Treatment of various oximes and hydrazones with dinitrogen tetroxide at low temperature in acetonitrile gave the corresponding ketones respectively in excellent yields.
- Shim, Sung Bo,Kim, Kweon,Kim, Yong Hae
-
p. 645 - 648
(2007/10/02)
-
- FACILE CONVERSION OF TOSYLHYDRAZONES TO THE CARBONYL COMPOUNDS USING PEROXYSULFUR INTERMEDIATE
-
Various tosylhydrazones, such as dialkyl and aryl-alkyl tosylhydrazones, were found to react with a peroxysulfur intermediate, which was generated by the reaction of 2-nitrobenzenesulfonyl chloride with superoxide, to be converted into the corresponding carbonyl compounds, in mostly quantitative yields, at -30 deg C under mild conditions.
- Kim, Yong Hae,Lee, Hyeon Kyu,Chang, Hae Sung
-
p. 4285 - 4288
(2007/10/02)
-
- TITANIUM TRICHLORIDE MEDIATED REDUCTION OF NITROSTYRENES
-
Reactions of substituted nitrostyrenes with aqueous titanium trichloride afforded pyrroles, carbonyl compounds, and oximes.In some instances, divinylamines were produced as well.The reaction mechanism is rationalized taking account of electron transfer to nitroethylenes from Ti(III), followed by protonation, dimerization, cyclization, and hydrolysis.
- Sera, Akira,Fukumoto, Shoji,Yoneda, Takako,Yamada, Hiroaki
-
p. 697 - 702
(2007/10/02)
-
- Photolysis of Vinyl Halides. Preferential Formation of Vinyl Cations by Copper(II) Salts
-
Photolysis of vinyl halides in the presence of copper(II) salts in a significant suppression of product formation derived from vinyl radicals.Photolysis of 1,1-diaryl-2-bromopropenes in the presence of copper(II) salts yielded no 1,1-diaryl-2-propenes.Photolysis of other vinyl halides, i.e., 1,1-diaryl-2-iodopropenes, 1,1-diaryl-2-bromoethylenes, and 1-bromo-2-(p-methoxyphenyl)ethylene, also led to a large decrease in the yields of the reduced olefins derived from the vinyl radicals.Copper(II) triflate was found to be more effective for the oxidation of vinyl radicals than copper(II) acetate.These reactions are explained by the intervention of vinylcopper intermediates and the formation of vinyl cations.
- Kitamura, Tsugio,Kobayashi, Shinjiro,Taniguchi, Hiroshi
-
p. 2641 - 2645
(2007/10/02)
-
- Synthesis of 2,2-Diphenyl-3-oxetanol Derivatives and Their Thermal or Acid-catalyzed Decomposition
-
A series of five different 2,2-diphenyl-3-oxetanols was synthesized by photocycloadditiion of benzophenone and enol trimethylsilyl ethers followed by protolysis of the resultant 3-trimethylsiloxyoxetanes.Thermal cleavage and acid-catalyzed rearrangement of these oxetanes are described.
- Shimizu, Nobujiro,Yamaoka, Shintaro,Tsuno, Yuho
-
p. 3853 - 3854
(2007/10/02)
-
- Dianions Derived from α-Halo Acids. The Darzens Condensation Revisited
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The dianions of α-halo carboxylic acids are readily generated by the addition of the acids to 2 equiv of lithium diisopropylamide at low temperatures.When the mixture warms to room temperature dimeric products are formed.When aldehydes and ketones were added to the cooled solutions of the dianions and the reaction mixtures were allowed to warm to room temperature, followed by acid quench, glycidic acids were formed.The glycidic acids, per se, were often too unstable to be isolated and purified but could be analyzed by conversion to their methyl esters withdiazomethane.When the reactions were quenched prematurely, α-chloro-β-hydroxy carboxylic acids were isolated.Homologated aldehydes and ketones were obtained from the glycidic acids by catalytic and thermal decarboxylation methods.
- Johnson, Carl R.,Bade, Thomas R.
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p. 1205 - 1212
(2007/10/02)
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- Rearrangement of vic-Diol Monoacetates Promoted by Organoaluminium Compounds
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Treatment of pinacol monoacetate with organoaluminium reagent R3Al caused the rearrangement under uptake of R as a nucleophile on the resulting carbonyl carbon, while R2AlSPh produced the pinacolone itself upon workup.
- Kanemoto, Shigekazu,Morizawa, Yoshitomi,Oshima, Koichiro,Nozaki, Hitosi
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p. 3941 - 3942
(2007/10/02)
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- Redox-Photosensitized Reactions. 5. Redox-Photosensitized Ring Cleavage of 1,1a,2,2a-Tetrahydro-7H-cyclobutindene Derivatives: Mechanism and Structure-Reactivity Relationship
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The mechanistic aspects of the redox-photosensitized chain cycloreversion of trans,syn-indene dimer 1 have been investigated in detail.The ? complex of 1 with the cation radical of phenanthrene (and selected other aromatic hydrocarbons) that is generated by photochemical electron transfer with p-dicyanobenzene has been shown to be a key intermediate by way of which the cycloreversion of 1 rapidly occurs without the formation of its cation radical; the rate constant for the cycloreversion has been determined to be 1*109 s-1.Redox photosensitization has been applied to the other related compounds and it has been found that the cyclobutanes which can undergo redox-photosensitized ring cleavage possess the phenyl group at C2.The importance of through-bond interactions between the two ?-electron system is discussed.
- Majima, Tetsuro,Pac, Chyongjin,Sakurai, Hiroshi
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p. 5265 - 5273
(2007/10/02)
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