- The Synthesis of α-Keto Acetals from Terminal Alkynes and Alcohols via Synergistic Interaction of Organoselenium Catalysis and Electrochemical Oxidation
-
Herein, an unprecedented electrochemical approach for the synthesis of α-keto acetals has been established from readily available terminal alkynes and alcohols. By merging the electrochemical and organoselenium-catalyzed processes, the desired products are obtained at room temperature in the absence of basic or metallic additives, with carbonyl and acetal motifs incorporated simultaneously across the triple bonds in a single operation.
- Ding, Ding,Xu, Liang,Wei, Yu
-
p. 4912 - 4917
(2022/03/02)
-
- Switchable Synthesis of Sulfoxides and α-Alkoxy-β-ketothioethers Regulated by Temperature in a Selectfluor-Methanol System
-
A switchable and benign protocol for chemoselective synthesis of sulfoxides and α-alkoxy-β-ketothioethers has been developed. It was determined that various thiophenols and alkenes/alkynes are compatible to realize the target compounds from a medium to a high yield by regulating the reaction temperature. In particular, methanol not only served as a solvent but also participated in the reaction process as a hydrogen donor. In this study, Selectfluor has been proved to be an efficient multifunctional reagent in the reaction system.
- Wang, Jiateng,Liu, Mengxia,Zhang, Yue,Bi, Gehua,Zhao, Yi,Yang, Kai,Huang, Xin
-
p. 14404 - 14419
(2021/11/01)
-
- Rapid, One-Step Synthesis of α-Ketoacetals via Electrophilic Etherification
-
Herein, we report a rapid, one-step synthesis of α-ketoacetals via electrophilic etherification of α-alkoxy enolates and monoperoxyacetals. Methyl, primary, and secondary α-ketoacetals were obtained in 44-63% yields from tetrahydropyranyl substrates; usin
- Paris, Timothy J.,Schwartz, Chris,Sundall, Eric,Willand-Charnley, Rachel
-
p. 14797 - 14811
(2021/10/20)
-
- Synergistic Catalysis of Se and Cu for the Activation of α-H of Methyl Ketones with Molecular Oxygen/Alcohol to Produce α-Keto Acetals?
-
Selenium and copper synergistically catalyzed the oxidation/alkoxylation of methyl ketones to synthesize α-keto acetals directly. Using O2 as oxidant and alcohol as solvent and alkoxylation reagent, the reaction is practical from industrial viewpoint. Mechanistic studies revealed that copper promoted the oxidation of organoselenium intermediates with O2 to allow the key rearrangement and selenoxide syn-elimination regenerating the catalytically active organoselenium species.
- Chen, Chao,Cao, Zhicheng,Zhang, Xu,Li, Yiming,Yu, Lei,Jiang, Xuefeng
-
p. 1045 - 1051
(2020/06/30)
-
- Green synthesis of 2, 2-dialkoxy acetophenone derivative
-
The invention provides green synthesis of a 2, 2-dialkoxy acetophenone derivative (1), and the structure of the 2, 2-dialkoxy acetophenone derivative (1) is shown as follows, wherein R is alkyl, and R1 is one or more of alkyl, halogen, alkoxy, N, N-dialkylamine or benzoring. According to the method, the 2, 2-dichloroacetophenone derivative, alcohol and alkali are taken as raw materials and are subject to heating and stirring to obtain a target product 2, filtering is performed after the reaction is completed, filtrate is concentrated, and a high-yield and high-purity product can be obtained. The method has the advantages of simple operation, few byproducts, and no generation of any toxic or environmentally harmful substances in the reaction. A new synthesis method is provided for the target product 1.
- -
-
Paragraph 0017
(2020/04/17)
-
- Iridium-Catalyzed Asymmetric Hydrogenation of Unsaturated Piperazin-2-ones
-
Two different iridium catalyst systems, generated from the ruthenocene-based phosphine-oxazoline ligand tBu-mono-RuPHOX or the diphosphine ligand BINAP, were developed for the asymmetric hydrogenation of 5,6-dihydropyrazin-2(1H)-ones, affording chiral piperazin-2-ones in good yields and with moderate to good ees. Different catalytic behaviors for the hydrogenation of these types of substrate were observed with these two catalyst systems. Our tBu-mono-RuPHOX ligand, which bears a ruthenocene scaffold with planar chirality, was found to be the best ligand for the [Ir(L)(COD)]BArF catalyst system, affording the desired products with up to 94% ee. (Figure presented.).
- Wang, Yanzhao,Liu, Yuanyuan,Li, Kun,Yang, Guoqiang,Zhang, Wanbin
-
supporting information
p. 1933 - 1941
(2017/06/09)
-
- Cu-catalyzed aerobic oxygenation of 2-phenoxyacetophenones to alkyloxy acetophenones
-
Cu-catalyzed aerobic oxygenation of 2-phenoxyacetophenones in the presence of alcohols was reported, and the corresponding alkyl benzoates, alkyloxy acetophenones and phenols were produced in high yields.
- Liu, Xinwei,Xu, Huanjun,Ma, Zhishuang,Zhang, Hongye,Wu, Cailing,Liu, Zhimin
-
p. 27126 - 27129
(2016/03/25)
-
- New synthesis technology of methyl benzoylformate
-
The invention relates to a brand new synthesis technology of a photoinitiator and herbicide metamitron intermediate methyl benzoylformate. The technology has not been reported in literatures. The technology comprises the following steps: acetophenone used as an initial raw material reacts with methyl nitrite under the action of hydrogen chloride to obtain 2,2-dimethoxyacetophenone, 2,2-dimethoxyacetophenone undergoes chlorine chlorination (or bromine bromination) under the catalysis action of a catalyst 4-methyl-2,6-di-tert-butyl phenol, and a molecule of haloalkane is removed from the chlorinated or brominated 2,2-dimethoxyacetophenone to obtain methyl benzoylformate. Influences of hydrogen chloride on the production of 2,2-dimethoxyacetophenone in the reaction and influences of the catalyst 4-methyl-2,6-di-tert-butyl phenol on the production of methyl benzoylformate are researched to determine the optimal conditions of the production of methyl benzoylformate. The new technology provided by the invention is simple to operate, and is economical.
- -
-
Paragraph 0026
(2017/08/25)
-
- Sodium iodide-catalyzed direct α-alkoxylation of ketones with alcohols via oxidation of α-iodo ketone intermediates
-
The direct α-alkoxylation of ketones with alcohols via a sodium iodide-catalyzed oxidative cross-coupling has been developed. This protocol enables a range of alkyl aryl ketones to cross couple with an array of alcohols in synthetically useful yields. The mechanistic studies provided solid evidence supporting that an α-iodo ketone was a key reaction intermediate, being converted into an α-alkoxylated ketone via further oxidation to a hypervalent iodine species rather than a common nucleophilic substitution, and was generated from the ketone starting material via a radical intermediate. These new mechanism insights should have an effect on the design of iodide-catalyzed oxidative cross-coupling reactions between nucleophiles.
- Zhu, Cuiju,Zhang, Yuanfei,Zhao, Huaiqing,Huang, Shijun,Zhang, Min,Su, Weiping
-
supporting information
p. 331 - 338
(2015/02/19)
-
- Unusual tandem oxidative C-C bond cleavage and acetalization of chalcone epoxides in the presence of iodine in methanol
-
An unusual reaction of chalcone epoxides is observed where chalcone epoxides on heating with iodine in methanol leads to α,α- dimethoxyacetophenones, through C-C bond cleavage followed by acetalization of the formyl group. The process occurs through ring
- Jadhav, Balaso G.,Samant, Shriniwas D.
-
supporting information
p. 1591 - 1595
(2014/07/08)
-
- Efficient preparation of α-ketoacetals
-
The Weinreb amides 2a,b were prepared from the a,a-dimethoxyacetic acids 1c,d. A number of representative nucleophilic additions (RMgX and RLi) on 2 afforded a-ketoacetals 3a-j in 70-99% yield. These compounds represent a versatile arrangement of functional groups of significant synthetic value, as demonstrated in the synthesis of (±)-salbutamol.
- Ayala-Mata, Francisco,Barrera-Mendoza, Citlalli,Jimenez-Vazquez, Hugo A.,Vargas-Diaz, Elena,Zepeda, L. Gerardo
-
p. 13864 - 13878
(2013/03/13)
-
- Enantioselective cyanosilylation of α,α-dialkoxy ketones catalyzed by proline-derived in-situ-prepared N-oxide as bifunctional organocatalyst
-
Bifunctional N,N′-dioxide catalysts have been developed for highly enantioselective cyanosilylation of α,α-dialkoxy ketones. This process, catalyzed by in-situ-prepared proline-derived N,N′-dioxide 2b, produced the corresponding cyanohydrin trimethylsilyl ethers in excellent yields (up to 99%) with high enantioselectivities (up to 93% ee). A reasonable mechanism was proposed according to the observation of the linear effect, 1H NMR spectra, isolated cyanohydrin, and the roles of the NH and N-oxide moieties of the catalyst.
- Qin, Bo,Liu, Xiaohua,Shi, Jian,Zheng, Ke,Zhao, Haitao,Feng, Xiaoming
-
p. 2374 - 2378
(2007/10/03)
-
- Solvent directed electrophilic iodination and phenylselenenylation of activated alkyl aryl ketones
-
A mixture of molecular iodine and phenyliodine(III) bis(trifluoroacetate) (BTI) in CH3CN (or CH3OH) iodinates the aromatic ring of some activated alkyl aryl ketones. A different outcome results if PhSeSePh is used instead of I2
- Panunzi, Barbara,Rotiroti, Lucia,Tingoli, Marco
-
p. 8753 - 8756
(2007/10/03)
-
- YCL3-catalyzed highly selective conversion of arylglyoxal to α-aryl- α-hydroxyacetic ester: Dramatic influence of base
-
Yttrium chloride catalyzed reaction of arylglyoxal and alcohol resulted in highly selective formation of α-aryl-α-hydroxyacetic ester under the influence of an added base (triethylamine, pyridine, piperidine) and afforded acetal in the absence of the base. The possible role of the additive (base) is discussed.
- Likhar, Pravin R.,Bandyopadhyay, Ananda K.
-
p. 538 - 540
(2007/10/03)
-
- Novel cerium(IV) ammonium nitrate mediated transformation of styrenes to α-methoxy acetophenones
-
Styrenes when treated with a methanolic solution of CAN underwent a novel transformation to α-methoxy acetophenones presumably via a radical cation.
- Nair, Vijay,Nair, Latha G.,Panicker, Sreeletha B.,Sheeba,Augustine, Anu
-
p. 584 - 585
(2007/10/03)
-
- Cadmium iodide catalyzed and efficient synthesis of acetals under microwave irradiations
-
A new selective method of acetalization of aldehydes and ketones with 1,2-diols, 1,3-diols or alcohols mediated by cadmium iodide under microwave irradiation is achieved in excellent yields.
- Laskar, Dhrubojyoti Dey,Prajapati, Dipak,Sandhu, Jagir S.
-
p. 1283 - 1284
(2007/10/03)
-
- Synthetic use of poly[4-(diacetoxyiodo)styrene] for organic reactions
-
Poly[4-(diacetoxyiodo)styrene] is sufficiently reactive for the iodination of aromatics, the oxidative 1,2-aryl migration of alkyl aryl ketones, the α-hydroxylation of ketones, and the oxidation of hydroquinones and sulfides similarly to (diacetoxyiodo)benzene. Here, those reactions with poly[4-(diacetoxyiodo)styrene] are very useful because of the simple operation; thus, filtration gives the crude products and recovered poly(4- iodostyrene), and then poly[4-(diacetoxyiodo)-styrene] can be regenerated by oxidation of the recovered poly(4-iodostyrene), which are reused for the same reactions.
- Togo, Hideo,Abe, Seiichiro,Nogami, Genki,Yokohama, Masataka
-
p. 2351 - 2356
(2007/10/03)
-
- Liquid photoinitiator mixtures
-
Liquid highly active photoinitiators are obtained by dissolving a solid photoinitiator of the titanocene type in liquid photoinitiators of the acetal or ketal type. The liquid mixtures have a long dark storage stability.
- -
-
-
- (Benzotriazol-1-yl)methoxymethyl anion: A novel methylal anion equivalent
-
The title anion readily reacts with a variety of electrophiles to give adducts which, upon treatment with methanol in the presence of p-toluenesulfonic acid, afford the corresponding α-functionalized dimethyl acetals.
- Katritzky,Yang,Cundy
-
p. 3061 - 3071
(2007/10/02)
-
- Oxygen-containing titanocenes, and the use thereof
-
Titanocenes of the formula I STR1 in which R1 are cyclopentadienyl? groups and R2 and R3 are aromatic radicals which are substituted in both ortho-positions by fluorine and, in addition, are substituted by an acyloxy group are suitable as photoinitiators for the photopolymerization of ethylenically unsaturated compounds.
- -
-
-
- Preparation of α,α-dialkoxy ketones
-
A process for preparing α,α-dialkoxy ketones of the formula I STR1 where R1 and R2 are each, independently of one another, hydrogen, C1 -C20 -alkyl, C3 -C20 -cycloalkyl, C4 -Csu
- -
-
-
- Selenium-Mediated Conversion of Alkynes into α-Dicarbonyl Compounds
-
The reaction of terminal and internal alkynes with diphenyl diselenide and ammonium peroxydisulfate in methanol proceeds smoothly to give α-keto acetals and α-keto ketals, respectively.This one-pot procedure is suggested to proceed through the initial formation of phenylselenenyl sulfate, a strong electrophilic reagent which effects the methoxyselenenylation of the alkynes.The addition products thus formed suffer methoxydeselenenylation giving the observed products and regenerating the phenylselenenylating agent.In some cases the reaction can be carried out using only catalytic amounts of diphenyl diselenide.The same reaction carried out in the presence of water or of ethylene glycol gives the unprotected or the diprotected α-dicarbonyl compounds, respectively.
- Tiecco, Marcello,Testaferri, Lorenzo,Tingoli, Marco,Chianelli, Donatella,Bartoli, Donatella
-
p. 4529 - 4534
(2007/10/02)
-
- Titanocenes, the use thereof, and N-substituted pyrroles
-
Titanocenes containing two 5-membered cyclodienyl groups, for example cyclopentadienyl, and one or two 6-membered carbocyclic or 5- or 6-membered heterocyclic aromatic rings which are substituted by a fluorine atom in at least one of the two ortho-positions to the titanium-carbon bond and contain, as a further substituent, unsubstituted or substituted 1-pyrryl, are suitable as photoinitiators for radiation-induced polymerization of ethylenically unsaturated compounds.
- -
-
-
- Titanocenes, the use thereof, and n-substituted fluoroanilines
-
Titanocenes containing two 5-membered cyclodienyl gropus, for example cyclopentadienyl, and one or two 6-membered carbocyclic or 5- or 6-membered heterocyclic aromatic rings which are substituted by a fluorine atom in at least one of the two ortho-positions to the titanium-carbon bond and contain, as further substituents, a substituted amino radical, are suitable as photoinitiators for radiation-induced polymerization of ethylenically unsaturated compounds.
- -
-
-
- Novel nitrogen-containing titanocenes, and the use thereof
-
Titanocenes of the formula I STR1 in which R1 are cyclopentadienyl? groups and R2 and R3 are aromatic radicals which are substituted in both ortho-positions by fluorine and, in addition, are substituted by a pyrrylalkyl group, amidoalkyl group or imidoalkyl group, are suitable as photoinitiators for the photopolymerization of ethylenically unsaturated compounds.
- -
-
-
- Selenium-Catalyzed Conversion of Methyl Ketones into α-Keto Acetals
-
The reaction of methyl ketones with catalytic amounts of diphenyl diselenide and an excess of ammonium peroxydisulfate in methanol proceeds smoothly to afford α-keto acetals in good yield.In some cases reaction yields were increased by using stoichiometri
- Tiecco, M.,Testaferri, L.,Tingoli, M.,Bartoli, D.
-
p. 4523 - 4528
(2007/10/02)
-
- 4,5- AND 2,5-ADDITIONS TO OXAZOLES
-
An investigation of the reaction of variously substituted oxazoles 1a-1 with Br2 in methanol revealed the formation of non-aromatic addition products.In general the presence of an aromatic substituent at the 4-position of oxazoles or the presence of a 4-methyl group if the 2-substituent is also aliphatic favors formation of 2,5-dimethoxy-3-oxazolines 3, while an aromatic substituent at the 2-position favors formation of ring-opened amides 2 or 7 or of 4,5-dimethoxy-2-oxazolines 5.Valuable information about intermediates in these reaction can be obtained by following the bromination of 1 in CD3OD by 1H- and 13C-NMR.
- Hassner, Alfred,Fischer,Bilha
-
p. 6249 - 6262
(2007/10/02)
-
- Catalytic Role of Copper Triflate in Lewis Acid Promoted Reactions of Diazo Compounds
-
Copper(II)trifluoromethanesulfonate is often a superior catalyst for transformations of diazo compounds that are normally promoted by boron trifluoride etherate.Formal carbon-oxygen insertion occurs when ortho esters are reacted with diazocarbonyl compounds in the presence of Cu(OTf)2, although the use of BF3*Et2O provides higher yields of insertion products.In contrast, the β,γ-unsaturated diazo ketone 6 undergoes intramolecular cyclization to produce the corresponding cyclopentenone in higher yield with Cu(OTf)2 catalysis than with the use of BF3*Et2O.Intamolecular cyclopropanation of the γ,δ-unsaturated diazo ketone 8 occurs in exceptionally high yield in the presence of Cu(OTf)2, whereas with BF3*Et2O intramolecular cyclization occurs with extensive rearrangement anf fluoride transfer.Copper(II)triflate is unique among transition-metal catalysts that are normally employed for reactions with diazo compounds in its effectiveness for these transformations.
- Doyle, Michael P.,Trudell, Mark L.
-
p. 1196 - 1199
(2007/10/02)
-
- Nitrosamine Photolysis as a Synthetic Method: The Addition of Aminium Radicals to Unsaturated Carbon-Carbon Bonds
-
Acid complexed nitrosamines decompose from their lowest singlet excited state to gine aminium radicals and nitric oxide radical transients.Aminium radicals initiate addition of various unsaturated groups to give 1-amino-2-nitroso compounds under an inert atmosphere, or 1-amino-2-nitrates under oxygen.In this report, photoaddition of nitroamines to olefins, acetylenes and fused aromatic hydrocarbons, and the subsequent transformations of the intermediates are described.Aminium radical initiated intramolecular cyclization to prepare tetracyclic aza compounds is also described.While photoaddition of nitrosamines to 4-propenylanisole or 3-butenol wes efficient, that to 3-butenyl benzoates under oxidative conditions was only fair, obviously due to the presence of a benzene ring.The oxidative photoaddition to 3-butenyl halide was followed by spontaneous cyclization to an azaspiro compound.The photoaddition to phenyl-substituted acetylenes gave β-nitroso enamines which hydrolyzed to diketomonoximes under neitral conditions but decomposed extensively under acidic conditions.Certain fused aromatic hydrocarbons acted as singlet sensitizers as well as substrates to induce similar addition giving amino nitroso adducts.These adducts took different courses of conversion dependent on reaction conditions, and on steric and electronic factors.
- Chow, Yuan L.,Colon, Carlos J.,Chang, Dawid W. L.,Pillay, K. Somasekharen,Lochart Robert D.,Tezuka, Takahiro
-
p. 622 - 634
(2007/10/02)
-
- Conversion of Aromatic Ketones into α-Arylalkanoic Acids. Oxidation by Thallium(III) and by Halogens
-
The mechanism by which thallium (III) nitrate oxidises aromatic ketones to α-arylalkanoic acids has been investigated and the role of additives in the system elucidated.It is found that in the absence of additives an organothallium intermediate, most probably the phenacylthallium species BzCH2Tl(NO3)2, persists and that the key to an efficient rearrangement is the ready conversion of this compound into its acetal.Thallium(III) is shown not to be a unique reagent for the oxidation.Other oxidants capable of acting initially as an electrophile and then as a leaving group are equally effective, provided that formation of an acetal is possible.Iodine-silver nitrate in particular offers considerable advantages as reagent over thallium(III).Higher specificity is achieved, unwanted side-reactions can be avoided, and toxicity problems are eliminated.Bromine may be used instead of iodine, but chlorine proves unsatisfactory as an oxidant.
- Higgins, Stanley D.,Thomas, Barry C.
-
p. 235 - 242
(2007/10/02)
-
- Rearrangement of 1-Aryl-2,2-dihalo-1-alkanones
-
Reaction of 1-aryl-2,2-dichloro-1-alkanones with alkoxides in the corresponding alcohol afforded a mixture of 1-aryl-2,2-dialkoxy-1-alkanones and 1-aryl-1,1-dialkoxy-2-alkanones.The mechanism was shown to proceed via α-chloro-α'-alkoxy epoxides, which rearranged into 1-alkoxy-1-aryl-1-chloro-2-alkanones, the latter giving the final compounds via either another epoxide intermediate or a solvolysis mechanism. α,α-Dibromo- and α-bromo-α-chloroalkyl aryl ketones behaved analogously, but α-bromo-α-fluoro- and α-chloro-α-fluoroalkyl aryl ketones gave exclusively solvolysis of initially formed 1-alkoxy-1-aryl-1-fluoro-2-alkanones, resulting in rearranged 1-aryl-1,1-dialkoxy-2-alkanones. α,α-Difluoroalkyl aryl ketones did not rearrange but underwent reduction of the carbonyl function on treatment with sodium methoxide in methanol.The influence of varying factors, such as the steric requirements of the alkoxide and the substrate, the concentration of the alkoxide, the aromatic substituent, the temperature, and the halogens, was investigated and correlated to the mechanism involved.
- Kimpe, Norbert De,Verhe, Roland,Buyck, Laurent De,Schamp, Niceas
-
p. 2803 - 2813
(2007/10/02)
-
- Pyrrole Annulation onto Aldehydes and Ketones via Palladium-Catalyzed Reactions
-
α-Dicarbonyl systems reacted with vinylmagnesium bromide and acetic anhydride to give α-acetoxy-α-vinylalkanones.These substrates react with benzylamine in the presence of tetrakis(triphenylphosphine)palladium to give N-benzylpyrroles with substituents in the two and/or three position.The functiodifferentiated synthesis of α-dicarbonyl compounds from ketones makes this a pyrrole annulation onto any α-methylene carbonyl system.
- Trost, Barry M.,Keinan, Ehud
-
p. 2741 - 2746
(2007/10/02)
-