- Asymmetric Catalytic Epoxidation of Terminal Enones for the Synthesis of Triazole Antifungal Agents
-
An enantioselective epoxidation of α-substituted vinyl ketones was realized to construct the key epoxide intermediates for the synthesis of various triazole antifungal agents. The reaction proceeded efficiently in high yields with good enantioselectivities by employing a chiral N,N′-dioxide/ScIII complex as the chiral catalyst and 35% aq. H2O2 as the oxidant. It enabled the facile transformation for optically active isavuconazole, efinaconazole, and other potential antifungal agents.
- Feng, Xiaoming,He, Qianwen,Liu, Xiaohua,Zhang, Dong,Zhang, Fengcai
-
supporting information
p. 6961 - 6966
(2021/09/11)
-
- Ketone Synthesis from Benzyldiboronates and Esters: Leveraging α-Boryl Carbanions for Carbon-Carbon Bond Formation
-
An alkoxide-promoted method for the synthesis of ketones from readily available esters and benzyldiboronates is described. The synthetic method is compatible with a host of sterically differentiated alkyl groups, alkenes, acidic protons α to carbonyl groups, tertiary amides, and aryl rings having common organic functional groups. With esters bearing α-stereocenters, high enantiomeric excess was maintained during ketone formation, establishing minimal competing racemization by deprotonation. Monitoring the reaction between benzyldiboronate and LiOtBu in THF at 23 °C allowed for the identification of products arising from deborylation to form an α-boryl carbanion, deprotonation, and alkoxide addition to form an "-ate" complex. Addition of 4-trifluoromethylbenzoate to this mixture established the α-boryl carbanion as the intermediate responsible for C-C bond formation and ultimately ketone synthesis. Elucidation of the role of this intermediate leveraged additional bond-forming chemistry and enabled the one-pot synthesis of ketones with α-halogen atoms and quaternary centers with four-different carbon substituents.
- Lee, Boran,Chirik, Paul J.
-
supporting information
p. 2429 - 2437
(2020/03/03)
-
- Synthesis of α-Borylated Ketones by Regioselective Wacker Oxidation of Alkenylboronates
-
As part of a program aimed at metal-catalyzed oxidative transformations of molecules with carbon-metalloid bonds, the synthesis of α-borylated ketones is reported via regioselective TBHP-mediated Wacker-type oxidation of N-methyliminodiacetic acid (MIDA)-protected alkenylboronates. The observed regioselectivity correlates with the hemilabile nature of the B-N dative bond in the MIDA boronate functional group, which allows boron to guide selectivity through a neighboring group effect.
- Corless, Victoria B.,Holownia, Aleksandra,Foy, Hayden,Mendoza-Sanchez, Rodrigo,Adachi, Shinya,Dudding, Travis,Yudin, Andrei K.
-
supporting information
p. 5300 - 5303
(2018/09/12)
-
- AuCl3/AgSbF6-catalyzed rapid epoxide to carbonyl rearrangement
-
An efficient epoxide to carbonyl rearrangement using catalytic AuCl 3/AgSbF6 has been presented. The reactions are fast and high yielding. β-Hydrogen migration takes place exclusively when hydrogen and methyl or substituted methyl groups are present at β-carbon of epoxide. When phenyl/acetyl/benzoyl and hydrogen are available at same carbon atom, migration of the former is preferred over the latter.
- Gudla, Vanajakshi,Balamurugan, Rengarajan
-
p. 5243 - 5247
(2012/11/07)
-
- β-Keto esters derived from 2-(trimethylsilyl)ethanol: An orthogonal protective group for β-keto esters
-
β-Keto esters derived from 2-(trimethylsilyl)ethanol undergo cleavage and decarboxylation when treated with 0.75 equivalents of tetrabutylammonium fluoride trihydrate in tetrahydrofuran at 50°C, while β-keto esters derived from methanol, tert-butyl alcohol, allyl alcohol, or benzyl alcohol stay intact. Conversely, methyl-, tert-butyl-, allyl-, or benzyl β-keto esters can be cleaved and decarboxylated without the 2-(trimethylsilyl)ethyl β-keto esters being affected. Similarly, mixed bis(β-keto esters) derived from 2-(trimethylsilyl)ethanol and methanol, tert-butyl alcohol, allyl alcohol, or benzyl alcohol can be defunctionalized chemoselectively under the same reaction conditions. Georg Thieme Verlag Stuttgart.
- Knobloch, Eva,Brueckner, Reinhard
-
scheme or table
p. 2229 - 2246
(2009/04/08)
-
- TiCl4-catalyzed indirect anti-Markovnikov hydration of alkynes: Application to the synthesis of benzo[b]furans
-
(Chemical Equation Presented) An efficient methodology for the indirect anti-Markovnikov hydration of unsymmetrically substituted terminal and internal alkynes is based on TiCl4-catalyzed hydroamination reactions. Its application to ortho-alkynylhaloarenes, followed by a copper-catalyzed O-arylation, provides flexible access to substituted benzo[b]furans.
- Ackermann, Lutz,Kaspar, Ludwig T.
-
p. 6149 - 6153
(2008/02/09)
-
- Highly efficient Pd-catalyzed carbonylative cross-coupling reactions with tetraorganoindates
-
Tetraorganoindates, which were prepared easily from the reaction of 1 equiv of InCl3 with 4 equiv of organometallics, could be employed as effective nucleophilic cross-coupling partners in Pd-catalyzed carbonylative cross-coupling reactions with a variety of organic electrophiles. The present method gave unsymmetrical ketones and 1,4-diacylbenzenes in good yields with highly efficient transfer of almost all the organic groups attached to the indium under a carbon monoxide atmosphere in THF at 60 °C.
- Lee, Sung Wook,Lee, Kooyeon,Seomoon, Dong,Kim, Sundae,Kim, Hyunseok,Kim, Hyun,Shim, Eunkyong,Lee, Miae,Lee, Seokju,Kim, Misook,Lee, Phil Ho
-
p. 4852 - 4855
(2007/10/03)
-
- Samarium(II)-mediated reactions of γ,δ-unsaturated ketones. Cyclization and fragmentation processes
-
(Matrix Presented) On treatment with samarium(II) iodide, γ,δ-unsaturated ketones undergo very different processes depending upon the nature of the reaction conditions. Employing samarium(II) iodide and MeOH, functionalized syn-cyclopentanol products are obtained stereoselectively. Mechanistic studies suggest that this cyclization occurs via a sequential reduction/intramolecular aldol reaction. With samarium(II) iodide and HMPA, products of a 4-exo-trig cyclization and of an interesting fragmentation reaction are observed.
- Hutton, Thomas K.,Muir, Kenneth,Procter, David J.
-
p. 2345 - 2347
(2007/10/03)
-
- A facile and highly efficient route to a traceless pi-arene chromium linker. Applications to synthetic and combinatorial chemistry.
-
[reaction--see text] A simple and efficient method for the attachment of functionalized arene chromium carbonyls to a polymeric support has been developed. A highly efficient solid-phase synthesis of tertiary alcohols and esters was performed in a traceless manner using this strategy. The linker-fabrication protocol permits simultaneous immobilization of various substrates on the solid support.
- Rigby,Kondratenko
-
p. 3683 - 3686
(2007/10/03)
-
- A simple method for the synthesis of substituted benzylic ketones: Homologation of aldehydes via the in situ generation of aryldiazomethanes from aromatic aldehydes
-
A general method for the homologation of aldehydes to benzylic ketones has been developed. Aryldiazomethanes were generated in situ in the presence of an aldehyde by simply heating the tosylhydrazones of aromatic aldehydes in the presence of a stoichiometric amount of base in polar protic solvents. The resulting polar protic solvent promoted homologation afforded benzylic ketones in moderate to excellent yields with a variety of aldehydes. Isolation of the tosylhydrazones was not necessary; they could be prepared in ethanol and carried through the sequence without isolation. This methodology allows easy access to a wide variety of substituted aryldiazomethanes that would be difficult, or even impossible, to prepare via conventional methods and circumvents the toxicity and stability problems associated with the isolation and/or handling solutions of aryldiazomethanes.
- Angle, Steven R.,Neitzel, Martin L.
-
p. 6458 - 6461
(2007/10/03)
-
- Intramolecular meta photocycloaddition of conformationally restrained 5-phenylpent-1-enes. Part II: Steric and electronic effects caused by 4-mono- and 4-disubstitution
-
The meta photocycloaddition of 4-substituted 5-phenylpent-1-enes. 10-18, has been studied. The monosubstituted derivatives always prefer 2,6 addition, independent of the size of the substituent. For 2,6 addition two basic conformations are possible. Disubstituted compounds yield predominantly 1,3 addition with the sterically more demanding group exo. Except for the methoxymethyl and THF derivative the oxygen is found exo as a result of repulsion, while the monohydroxy derivative gives also endo which might be explained by hydrogen bonding. The products from compound 11 change from mainly endo-OH in cyclohexane to chiefly exo-OH in methanol. Much similarity is found with Diels-Alder cycloaddition.
- Barentsen, Helma M.,Sieval, Alex B.,Cornelisse, Jan
-
p. 7495 - 7520
(2007/10/02)
-
- Selenium-assisted reduction of α- and β-diketones with carbon monoxide and water
-
Phenyl substituted α- (PhC(=O)C(=O)R) and β-diketones (PhC(=O)CHRC(=O)R′) are reduced by carbon monoxide and water in the presence of elemental selenium to give the corresponding aromatic ketones in moderate to good yields.
- Nishiyama, Yutaka,Inoue, Jun,Teranishi, Kazuyo,Moriwaki, Masami,Hamanaka, Sawako
-
p. 6347 - 6350
(2007/10/02)
-
- Reactions of Carbonyl Compounds with Grignard Reagents in the Presence of Cerium Chloride
-
The addition of Grignard reagents to ketones is significantly enhanced by cerium chloride with remarkable supression of side reactions, particularly enolization.Some esters, which are prone to side reactions, also react readily with Grignard reagents in the presence of cerium chloride to give normal reaction products in reasonable to high yields.
- Imamoto, Tsuneo,Takiyama, Noboyuki,Nakamura, Kimikazu,Hatajima, Toshihiko,Kamiya, Yasuo
-
p. 4392 - 4398
(2007/10/02)
-
- Electrochemical synthesis of ketones from acid chlorides and alkyl and aryl halides catalysed by nickel complexes
-
The nickel-catalysed electrochemical cross-coupling of acid chlorides and alkyl or aryl halides in acetonitrile affords unsymmetric ketones in good to high yields.The reaction can be performed under very simple and mild conditions in a diaphragmless cell.A zinc rod as the sacrificial anode has been found to be the most efficient.
- Marzouk, H.,Rollin, Y.,Folest, J. C.,Nedelec, J. Y.,Perichon, J.
-
p. C47 - C50
(2007/10/02)
-
- Reactions of Phenylethylenes with O(3P) Atoms in Condensed Phases
-
Oxidation of styrene, α- and β-alkyl-substituted styrenes, cis- and trans-stilbene, triphenylethylene, allylbenzene, and its trans β-alkyl-substituted derivatives with O(3P) resulted mainly in epoxides and carbonyl compounds formed by 1,2-H shifts.The O(3P) atoms were produced by microwave discharge of O2, CO2, or N2O/N2 in the presence of He.The temperature effect on the relative yields of products was studied on cis-stilbene and the regioselectivity of the O(3P) attack on the double bond in the series of β-alkylstyrenes and β-alkyl-substituted allylbenzenes.The mechanism of the oxidation is postulated to involve a diradical intermediate.The temperature effect is explained by the interconversion of different electronic states of this diradical and the steric effect by an early unsymmetric transition state for the addition of O(3P) atoms to the double bond.
- Zadok, Elazar,Rubinraut, Sara,Mazur, Yehuda
-
p. 385 - 390
(2007/10/02)
-
- AZO ANIONS IN SYNTHESIS. PT 1. t-BUTYLHYDRAZONES AS ACYL-ANION EQUIVALENTS
-
The lithium salts of aldehyde t-butylhydrazones react with electrophiles (aldehydes, ketones, alkyl halides, crotonates) to form C-trapped t-butylazo-compounds; tautomerisation and hydrolysis gave α-hydroxy ketones, ketones, and γ-keto esters in good yield, thereby providing a convenient new acyl-anion equivalent.Reaction of these lithium salts with aldehydes and ketones, followed by elimination provided a new route to azo alkenes.
- Baldwin, Jack E.,Adlington, Robert M.,Bottaro, Jeffrey C.,Kolhe, Jayant N.,Perry, Matthew W. D.,Jain, Ashok U.
-
p. 4223 - 4234
(2007/10/02)
-
- Alkylation of Benzene with α-Diazoketones via Cycloheptatrienyl Intermediates
-
Benzyl ketones can be synthesised efficiently from benzene and α-diazoketones with sequential catalysis by rhodium(II) trifluoroacetate and trifluoroacetic acid; the process involves cycloheptatrienyl intermediates.
- McKervey, M. Anthony,Russell, D. Noel,Twohig, M. Fiona
-
p. 491 - 492
(2007/10/02)
-
- Reaction of α-Silyl Esters with Grignard Reagents: A Synthesis of β-Keto Silanes and Ketones. Preparation of the Douglas Fir Tussock Moth Pheromone
-
A variety of α-diphenylmethylsilyl esters have been prepared and reacted with Grignard reagents.The reaction is relatively slow in refluxing THF and can be controlled to allow the addition of 1 equiv of the Grignard reagent, providing the corresponding β-keto silane.Protiodesilylation of the β-keto silane results in the overall conversion of an ester to a ketone.This ester to ketone methodology has been applied to a two-step synthesis of the pheromone of the Douglas fir tussock moth.The β-keto silanes are viable precursors to regioselectively generated enol silyl ethers.The reaction of ethyl 2-methyl-2-(diphenylmethylsilyl)propionate with vinylmagnesium bromide or 2-methyl 1-propenylmagnesium bromide results in the addition of 2 equiv of the Grignard reagent, the second in a Michael fashion.
- Larson, Gerald L.,Hernandez, David,Lopez-Cepero, Ingrid Montes de,Torres, Luz E.
-
p. 5260 - 5267
(2007/10/02)
-
- α,β-Epoxy Sulfoxides as Useful Intermediates in Organic Synthesis. I. A Novel Synthesis of Dialkyl Ketones and a Synthesis of Aldehydes from Ketones by One Carbon Elongation
-
Treatment of α,β-epoxy sulfoxides, prepared from 1-chloroalkyl phenyl sulfoxides with ketones or aldehydes, with sodium benzeneselenolate gives dialkyl ketones or aldehydes in good yields under mild conditions.The mechanism of this reaction and an application of this process to a formal total synthesis of dihydrojasmone are described.
- Satoh, Tsuyoshi,Kaneko, Youhei,Izawa, Takao,Sakata, Kiichi,Yamakawa, Koji
-
p. 1983 - 1990
(2007/10/02)
-
- Arylation and 1-Alkenylation on α-Position of Ketones via Tributyltin Enolates Catalyzed by Palladium Complex
-
The reaction of tributyltin enolates, prepared from tributyltin methoxide and enol acetates in situ, with aryl and 1-alkenyl bromides in the presence of dichlorobis(tri-o-tolylphosphine)palladium was found to give α-aryl and α-(1-alkenyl) ketones, respectively, in good yields with essentially complete retention of the enol acetate regiochemistry.
- Kosugi, Masanori,Hagiwara, Isao,Sumiya, Takao,Migita, Toshihiko
-
p. 241 - 246
(2007/10/02)
-
- A NOVEL SYNTHESIS OF DIALKYL KETONES AND α-SULFENYLATED CARBONYL COMPOUNDS FROM α,β-EPOXY SULFOXIDES
-
Treatment of α,β-epoxy sulfoides with excess sodium phenylselenide and various kinds of alkylthiolates gave dialkyl ketones and α-sulfenylated carbonyl compounds, respectively, in good yields under mild conditions.
- Satoh, Tsuyoshi,Kaneko, Youhei,Kumagawa, Takumi,Izawa, Takao,Sakata, Kiichi,Yamakawa, Koji
-
p. 1957 - 1960
(2007/10/02)
-
- Azo Anions in Synthesis. t-Butylhydrazones as Acyl-anion Equivalents
-
The lithium salts of aldehyde t-butylhydrazones react with electrophiles (aldehydes, ketones, alkyl halides) to form C-trapped t-butylazo compounds; isomerisation and hydrolyse gave α-hydroxy ketones and ketones in good yields, thereby providing a convenient new acyl-anion equivalent.
- Adlington, Robert M.,Baldwin, Jack E.,Bottaro, Jeffrey C.,Perry, Matthew W. D.
-
p. 1040 - 1041
(2007/10/02)
-
- Medium-ring Ketone Synthesis. Intramolecular Acylation of Sulfur-stabilized Carbanions: A Model Study
-
Intramolecular acylation of the sulfur-stabilized carbanions of the acyclic ester 9 and amide sulfides 11 was carried out as a model study for developing an effective method for the construction of medium-ring ketones by ring closure.Reaction of 9a-c or 11a-g with lithium diisopropylamide (LDA) proceeded smoothly and the expected keto sulfides 10a-c or 12a-g, respectively, were obtained.In the cases where R1 and/or R2 in 11 were normal alkyl groups, the reaction did not take place.However, these difficulties were readily overcome either by introducing a methyl group next to the carbonyl group or by converting the sulfides into the corresponding sulfoxides or sulfones.Acylation in the allyl sulfides 11b, d, f and the allyl sulfone 20b takes place at the α-position to the sulfur atom, yielding β,γ-unsaturated ketones.A reductive removal of the sulfide moiety or its conversion into other functional groups was also examined.
- Ohtsuka, Yasuo,Oishi, Takeshi
-
p. 443 - 453
(2007/10/02)
-
- α-Phenylation of Ketones via Tin Enolates Catalysed by a Palladium Complex
-
The reaction of tributyltin enolates, prepared from tributyltin methoxide and enol acetates in situ, with bromobenzene in the presence of a catalytic amount of PdCl2(o-tolyl3P)2 was found to give α-phenyl ketones in good yields with essentially complete retention of the acetate regiochemistry.
- Kosugi, Masanori,Hagiwara, Isao,Sumiya, Takashi,Migita, Toshihiko
-
p. 344 - 345
(2007/10/02)
-
- A Reinvestigation of the Pictet-Gams Isoquinoline Synthesis. Part 2. Formation of Rearranged Isoquinolines: the Δ2-Oxazoline-Isoquinoline Transformation
-
Cyclisation of a series of 2-substituted 2-acylamino-1-arylalkan-1-ols using phosphorus pentaoxide in refluxing decalin is shown to lead to rearranged, i.e. 4-substituted, isoquinolines in addition to the anticipated 3-substituted isomers.The products arise largely via 5-phenyl-Δ2-oxazoline intermediates and the formation of the rearranged isoquionolines from these intermediates is fully discussed.The pathway is not substantially altered when 2-benzamido-1-methoxy-1-phenylalkanes are cyclised.
- Ardabilchi, Nasser,Fitton, Alan O.,Hadi, A. Hamid b. A.,Thompson, J. Robin
-
p. 1710 - 1725
(2007/10/02)
-
- Synthese de methoxycarbonylindenes, dihydro-1,2 naphtalenes et benzocycloheptene. Obtention des indanones-1, des tetralones-1 et de la benzosuberone correspondantes
-
The synthesis of methoxycarbonylindenes, 1,2-dihydro-naphtalenes, and benzocycloheptene starting from the corresponding 1-indanones, 1-tetralones, and benzosuberone is reported.The starting ketones were synthesized by methods described in the literature which were optimized; in some cases new processes are described.
- Verbel, Joel,Carrie, Robert
-
p. 116 - 124
(2007/10/02)
-
- FACILE SYNTHESIS OF BENZYL KETONES BY THE REDUCTIVE COUPLING OF BENZYL BROMIDE AND ACYL CHLORIDES IN THE PRESENCE OF A PALLADIUM CATALYST AND ZINC POWDER
-
Benzyl ketones were obtained in good yields from benzyl bromide and acyl chlorides by the combined use of Zn and a palladium catalyst under mild conditions.
- Sato, Toshio,Naruse, Kouichi,Enokiya, Masashi,Fujisawa, Tamotsu
-
p. 1135 - 1138
(2007/10/02)
-
- EFFET DU BENZENE DANS LA REACTION DE GRIGNARD SUR LES NITRILES
-
Use of benzene containing one equivalent of ether as solvent in Grignard reactions of nitriles at room temperature, leads to increased yields of the corresponding ketones compared to results obtained for the same reactions in ether.A useful consequence of this is that undesirable side reactions are virtually eliminated.
- Canonne, Persephone,Foscolos, George B.,Lemay, Gilles
-
p. 155 - 158
(2007/10/02)
-
- Photostimulated Nucleophilic Aromatic Substitution for Halides with Carbon Nucleophiles. Preparative and Mechanistic Aspects
-
The photo-SRN1 reaction operates efficiently with enolate anions derived from simple ketones and esters, but 2-lithio-1,3-dithiane gives low yields.The sluggish and inefficient reaction of dialkyl-substituted ketone and ester enolates is traced to hydrogen atom transfer from the carbon adjacent to the enolate anion to the transient phenyl radical.The first systematic survey of intramolecular coupling of keton enolate anions shows that six-, seven-, eight-, and ten-membered rings can be formed, although the β-hydrogen transfer becomes important in certain cases.
- Semmelhack, M. F.,Bargar, Thomas
-
p. 7765 - 7774
(2007/10/02)
-