- Ruthenium-on-Carbon-Catalyzed Facile Solvent-Free Oxidation of Alcohols: Efficient Progress under Solid-Solid (Liquid)-Gas Conditions
-
A protocol for the ruthenium-on-carbon (Ru/C)-catalyzed solvent-free oxidation of alcohols, which proceeds efficiently under solid-solid (liquid)-gas conditions, was developed. Various primary and secondary alcohols were transformed to corresponding aldehydes and ketones in moderate to excellent isolated yields by simply stirring in the presence of 10% Ru/C under air or oxygen conditions. The solvent-free oxidation reactions proceeded efficiently regardless of the solid or liquid state of the substrates and reagents and could be applied to gram-scale synthesis without loss of the reaction efficiency. Furthermore, the catalytic activity of Ru/C was maintained after five reuse cycles.
- Park, Kwihwan,Jiang, Jing,Yamada, Tsuyoshi,Sajiki, Hironao
-
p. 1200 - 1205
(2021/12/29)
-
- Selective Visible Light Aerobic Photocatalytic Oxygenation of Alkanes to the Corresponding Carbonyl Compounds
-
The aerobic, selective oxygenation of alkanes via C-H bond activation is an important research challenge. Photocatalysis offers the potential for the introduction of additional concepts for such reactions. Visible light photoactive semiconductors such as bismuth oxyhalides (BiOX, X = Cl and Br) used in this research typically oxidize organic compounds through photocatalyzed formation of strongly oxidizing holes. The reactive oxygen species formed react with organic compounds in one-electron processes, leading to radical intermediates and nonselective oxidation. Such oxidation reactions generally lead to total oxidation. Here, impregnation of BiOX with a polyoxometalate, H5PV2Mo10O40, as a strong electron acceptor changed the reactivity of BiOX, leading to Mars-van Krevelen-type reactivity, that is, photoactivated oxygen donation from BiOX to the organic substrate followed by reoxidation by O2 and catalysis. This conclusion was supported by mechanistic studies involving isotope labeling studies. In this way, ethane was selectively oxidized to acetaldehyde in a flow reactor with a turnover number (24 h) of 415.
- Somekh, Miriam,Khenkin, Alexander M.,Herman, Adi,Neumann, Ronny
-
p. 8819 - 8824
(2019/09/30)
-
- Internal Alkyne Regio- and Chemoselectivity using a Zwitterionic N-Heterocyclic Carbene Gold Catalyst in a Silver-Free Alkyne Hydration Reaction
-
An alkyne hydration of terminal and internal alkynes is reported using a zwitterionic N-heterocyclic carbene gold catalyst [(BNHC)Au(SMe2)] in the absence of silver and Br?nsted acid additives. The hydration demonstrates good regioselectivity in alkyne hydration and chemoselectivity for internal alkynes vs. terminal. In addition, (BNHC)Au(SMe2) performs a propargyl alcohol hydration to predominantly form α-hydroxymethyl ketone over the more common Meyer–Schuster rearrangement product. While complex (BNHC)Au(SMe2) is active without silver additives, addition of silver hexafluoroantimonate (AgSbF6) increases reaction rate and decreases selectivity for internal alkyne hydration over terminal substrates. To the best of our knowledge, the rate enhancement of (BNHC)Au(SMe2) by AgSbF6is the first such demonstration of a silver effect for a “halide-free” Au catalyst. (Figure presented.).
- Weerasiri, Kushan C.,Chen, Danmin,Wozniak, Derek I.,Dobereiner, Graham E.
-
p. 4106 - 4113
(2016/12/30)
-
- Silver-containing microemulsion as a high-efficient and recyclable catalytic system for hydration of alkynes
-
A silver-catalyzed highly efficient and regioselective synthesis of ketones from a wide range of alkynes is described. The reaction is dramatically accelerated by its performance in aqueous emulsion, which is self-assembled by the addition of silver perfluorooctanesulfonate (1) and perfluorooctanesulfonic acid (PFOS) to water. The reaction is conducted under convenient conditions with broad substrate scope, including a variety of aromatic and aliphatic terminal alkynes and internal alkynes. Furthermore, the air- and light-stable silver catalytic microemulsion can be reused for 4 times with minimal change in catalytic efficiency.
- Dong, Qizhi,Li, Ningbo,Qiu, Renhua,Wang, Jinying,Guo, Cancheng,Xu, Xinhua
-
p. 122 - 127
(2015/10/12)
-
- Carbonylative enantioselective meso-desymmetrization of cis-epoxides to trans-β-lactones: Effect of salen-ligand electronic variation on enantioselectivity
-
Carbonylation catalysts for the desymmetrization of meso-epoxides yielding enantioenriched trans-β-lactones are reported. Fine-tuning the electronic properties of the ligand further improved enantioselectivity. The sterics of the substrate dictated whether a given electronic variation decreased or increased enantioenrichment, revealing an unexpected relationship between the substrate's steric environment and the electronic nature of the optimal catalyst.
- Mulzer, Michael,Lamb, Jessica R.,Nelson, Zachary,Coates, Geoffrey W.
-
supporting information
p. 9842 - 9845
(2014/08/18)
-
- Mild and direct conversion of esters to morpholine amides using diisobutyl(morpholino)aluminum: Application to efficient one-pot synthesis of ketones and aldehydes from esters
-
Morpholine amide intermediates, which are easily prepared by aminolysis of various esters with diisobutyl(morpholino)aluminum, react with organolithium and reducing agents (DIBALH or LDBMA) without isolation of the aminolysis intermediates to give ketones in 83-95% yields and aldehydes quantitatively.
- Jeon, Ah Ram,Kim, Min Eai,Park, Jae Kyo,Shin, Won Kyu,An, Duk Keun
-
p. 4420 - 4424
(2014/06/10)
-
- An effective one-pot conversion of acid chlorides to aldehydes and ketones
-
Aldehydes and ketones were synthesized from their respective acid chlorides via a one-pot protocol. Morpholine amide intermediates that were readily prepared by the aminolysis of various acid chlorides with diisobutyl(morpholino) aluminum smoothly reacted with the reducing agent LDBMA and the organolithium reagents under mild reaction conditions (0 C), giving almost excellent product yields of up to 95%.
- Park, Jae Kyo,Shin, Won Kyu,An, Duk Keun
-
p. 3199 - 3203
(2013/06/27)
-
- METHOD FOR MANUFACTURING KETONE
-
A method for manufacturing a ketone includes oxidizing an internal olefin or a cyclic olefin having one carbon-carbon double bond or more at a position other than terminals of a molecule thereof in an amide-based solvent in the presence of water, a palladium catalyst, and molecular oxygen, thereby bonding an oxo group to at least one of the carbon atoms constituting the carbon-carbon double bond, in which the amide-based solvent is represented by the formula in the formula (1), R1 represents an alkyl group having 1 to 4 carbon atoms, R2 and R3 each independently represent an alkyl group having 1 to 4 carbon atoms or an aryl group, and when R1 and R2 are alkyl groups, R1 and R2 may be bonded to each other to form a ring structure.
- -
-
Page/Page column 7
(2011/12/12)
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- KETONE MANUFACTURING METHOD
-
A method for manufacturing a ketone comprising: oxidizing an internal olefin or a cyclic olefin having one carbon-carbon double bond or more at a position other than terminals of a molecule thereof in an amide-based solvent in the presence of water, a palladium catalyst, and molecular oxygen, thereby bonding an oxo group to at least one of the carbon atoms constituting the carbon-carbon double bond, the amide-based solvent being represented by the following formula (1): (in the formula (1), R1 represents an alkyl group having 1 to 4 carbon atoms, R2 and R3 each independently represent an alkyl group having 1 to 4 carbon atoms or an aryl group, and when R1 and R2 are alkyl groups, R1 and R2 may be bonded to each other to form a ring structure).
- -
-
Page/Page column 9-10
(2011/10/04)
-
- H2O2-oxidation of alcohols promoted by polymeric phosphotungstate catalysts
-
A novel polymeric phosphotungstate catalyst bearing a poly(ethylene oxide-pyridinium) matrix was developed that efficiently promoted oxidation of a variety of alcohols, including highly sterically demanding neopentyl alcohols, with hydrogen peroxide, to afford the corresponding carbonyl compounds in up to quantitative yield. The chemoselective oxidation of sterically hindered secondary alcohols in the presence of primary alcohols was achieved. The catalyst could be reused four times without any loss of catalytic activity.
- Yamada, Yoichi M.A.,Jin, Chung Keun,Uozumi, Yasuhiro
-
supporting information; experimental part
p. 4540 - 4543
(2010/12/25)
-
- Wacker-type oxidation of internal olefins using a PdCl2/N,N- dimethylacetamide catalyst system under copper-free reaction conditions
-
(Figure Presented) A simple catalyst system consisting of PdCl2 and N,N-dimethylacetamide (DMA) as the solvent can successfully promote Wacker-type oxidation of internal olefins. This catalyst system does not require copper compounds and is tolerant of a wide range of substrates having internal olefins.
- Mitsudome, Takato,Mizumoto, Keiichi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
-
supporting information; experimental part
p. 1238 - 1240
(2010/05/17)
-
- Hg(OTf)2-catalyzed instantaneous hydration of β- and δ-hydroxy internal alkynes with complete regioselectivity
-
The hydration of β- and δ-hydroxy internal alkynes catalyzed by Hg(OTf)2 took place instantaneously to give ketones with complete regioselectivity under mild conditions, whereas the hydration of internal alkyne without hydroxy moiety was very slow and gave a mixture of ketones. If the hydroxy group is located more than five carbons from the triple bond it has no significant effect upon the hydration reaction. Georg Thieme Verlag Stuttgart.
- Nishizawa, Mugio,Takemoto, Takayuki,Sasaki, Ikuo,Nakano, Mayo,Ho, Elisabeth,Namba, Kosuke,Yamamoto, Hirofumi,Imagawa, Hiroshi
-
experimental part
p. 1175 - 1179
(2009/12/01)
-
- Regio- And stereoselective subterminal hydroxylations of n-decane by fungi in a liquid-liquid interface bioreactor (L-L IBR)
-
This article may be the first report to describe the excellent regio- and stereoselective subterminal hydroxylations of n-alkane with microorganisms. Approximately 2000 fungal strains were screened for the regioselective hydroxylation of n-decane with a s
- Oda, Shinobu,Isshiki, Kunio,Ohashi, Shinichi
-
experimental part
p. 105 - 109
(2009/04/10)
-
- Direct and efficient one-pot preparation of ketones from aldehydes using N-tert-butylphenylsulfinimidoyl chloride
-
(Chemical Equation Presented) A general, one-pot process has been established to prepare ketones from aldehydes using N-tert- butylphenylsulfinimidoyl chloride. By employing the developed protocol, a range of unsymmetrical ketones has been prepared in good yields from aldehydes in one simple synthetic operation.
- Crawford, James J.,Henderson, Kenneth W.,Kerr, William J.
-
p. 5073 - 5076
(2007/10/03)
-
- Semivolatile and volatile compounds in combustion of polyethylene
-
The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
- Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
-
p. 615 - 627
(2007/10/03)
-
- A hydroacylation-triggered carbon-carbon triple bond cleavage in alkynes via retro-Mannich type fragmentation
-
The carbon-carbon triple bond in alkyne is cleaved via hydroacylation followed by retro-Mannich type fragmentation in the presence of aldehyde, which triggers a successive C-C bond cleavage. Copyright
- Lee, Dae-Yon,Hong, Boo-Sun,Cho, Eung-Goo,Lee, Hyuk,Jun, Chul-Ho
-
p. 6372 - 6373
(2007/10/03)
-
- Ruthenium-catalyzed oxidation of alkanes with tert-butyl hydroperoxide and peracetic acid
-
The ruthenium-catalyzed oxidation of alkanes with tert-butyl hydroperoxide and peracetic acid gives the corresponding ketones and alcohols highly efficiently at room temperature. The former catalytic system, RuCl2(PPh3)3-t-BuOOH, is preferable to the oxidation of alkylated arenes to give aryl ketones. The latter system, Ru/C-CH3CO3H, is suitable especially for the synthesis of ketones and alcohols from alkanes. The ruthenium-catalyzed oxidation of cyclohexane with CH3CO3H in trifluoroacetic acid/CH2Cl2 at room temperature gave cyclohexyl trifluoroacetate and cyclohexanone with 90% conversion and 90% selectivity (85:15). The mechanistic study indicates that these catalytic oxidations of hydrocarbons involve oxo-ruthenium species as key intermediates.
- Murahashi,Komiya,Oda,Kuwabara,Naota
-
p. 9186 - 9193
(2007/10/03)
-
- Alkane oxidation with manganese substituted polyoxometalates in aqueous media with ozone and the intermediacy of manganese ozonide species
-
Manganese substituted polyoxometalates (POMs), such as Li12[MnII2ZnW(ZnW9O 34)2] were effective catalysts for the oxidation of alkanes to ketones with ozone in an aqueous reaction medium; a green intermediate compound observable by UV-VIS and ESR at -78 °C was postulated to be a reactive manganese ozonide species.
- Neumann, Ronny,Khenkin, Alexander M.
-
p. 1967 - 1968
(2007/10/03)
-
- Ruthenium-Catalyzed Oxidation of Alkanes with Peracids
-
The ruthenium-catalyzed oxidation of alkanes with peracids under mild conditions gives the corresponding ketones and alcohols highly efficiently.Similar treatment of alkanes in trifluoroacetic acid gives alkyl trifluoroacetates.
- Murahashi, Shun-Ichi,Oda, Yoshiaki,Komiya, Naruyoshi,Naota, Takeshi
-
p. 7953 - 7956
(2007/10/02)
-
- Cerium(III) chloride remarkably increases the rates of formation and yields of ketones in the reaction of lithium carboxylates with organolithiums
-
The presence of CeCl3 greatly increases the yield of ketones in the reaction of organolithiums with lithium carboxylates. The CE(III) suppresses the enolization of the lithium carboxylate, previously unrecognized as a competing reaction except in special cases, and the formation of tertiary alcohols. One of the reasons for the latter effect is a surprising increase in the rate of addition of the organometallic to the lithium carboxylate in the presence of Ce(III).
- Ahn, Yoonmo,Cohen, Theodore
-
p. 203 - 206
(2007/10/02)
-
- Conjugate Reduction of α,β-Unsaturated Carbonyl Compounds by Catecholborane
-
α,β-Unsaturated ketones which can readily adopt an s-cis conformation undergo conjugate reduction by catecholborane at room temperature. α,β-Unsaturated imides, esters, and amides are unreactive under the same conditions.However, catalytic quantities of Rh(PPh3)3Cl greatly accelerate the 1,4-addition process, effecting conjugate reduction of these substrates by catecholborane at -20 deg C.The resulting boron enolates may be reacted with electrophiles to provide functionalized products.
- Evans, David A.,Fu, Gregory C.
-
p. 5678 - 5680
(2007/10/02)
-
- A Convenient Method for the Direct Preparation of Ketones from Vinylsilanes with Molecular Oxygen Catalyzed by Cobalt(II) Complex
-
Various vinylsilanes are directly converted to the corresponding ketones in high yields on treatment with molecular oxygen in the presence of a catalytic amount of cobalt(II) complex under neutral condition.
- Kato, Koji,Mukaiyama, Teruaki
-
p. 2233 - 2236
(2007/10/02)
-
- BIS(TRIFLUOROACETYLACETONATO)COBALT(II) CATALYZED OXIDATION-REDUCTION HYDRATION OF OLEFINS SELECTIVE FORMATION OF ALCOHOLS FROM OLEFINS
-
Various olefins are hydrated with molecular oxygen (oxidant) and a secondary alcohol (reductant) in the presence of a catalytic amount of bis(trifluoroacetylacetonato)cobalt(II) in good yields
- Inoki, Satoshi,Kato, Koji,Takai, Toshihiro,Isayama, Shigeru,Yamada, Tohru,Mukaiyama, Teruaki
-
p. 515 - 518
(2007/10/02)
-
- Synthesis and Reactivity toward Acyl Chlorides and Enones of the New Highly Functionalized Copper Reagents RCu(CN)ZnI
-
The new and highly functionalized copper reagents RCu(CN)ZnI obtained from readily available primary and secondary alkylzinc iodides by a transmetalation in THF with the soluble salt, CuCN*2LiX, react in good yields with acyl chlorides and enones, respectively, to afford ketones and 1,4-addition products.
- Knochel, Paul,Yeh, Ming Chang P.,Berk, Scott C.,Talbert Jason
-
p. 2390 - 2392
(2007/10/02)
-
- Oxidative Cleavage of Carbon-Silicon Bonds by Dioxygen: Catalysis by a Flavin-Dihydronicotinamide Redox System
-
Carbon-silicon bonds in alkyloxy- or fluoro-silanes readily undergo cleavage by dioxygen (molecular oxygen), catalysed by tetra-acetylriboflavin (5-10 molpercent) in the presence of N-benzyl-1,4-dihydronicotinamide as reductant, together with fluoride ions as an essential additive.
- Tamao, Kohei,Hayashi, Takashi,Ito, Yoshihiko
-
p. 795 - 797
(2007/10/02)
-
- Methyl Group Migration in the Reactions of Alkynyltrialkylborates
-
It is shown that the methyl group cannot be used as a cheap, non-migrating group in the reactions of alkynyltrialkylborates with electrophiles.However, trimethylborane can be used as a methylboronating agent for alkynes, given the right choice of solvent, and this may be of use in terpene synthesis.
- Pelter, Andrew,Drake, Robert A.
-
p. 4181 - 4184
(2007/10/02)
-
- Conditions for the Microbial Oxidation of Various Higher Alcohols in Isooctane
-
The substrate specifities and reaction conditions for the microbial oxidation of higher alcohols in isooctane were investigated using Rhodococcus equi cells grown on n-tetradecane as the sole carbon source.Primary alcohols, C4ca.C14 (even numbers), were oxidized to the corresponding carboxylic acids, with which the substrate alcohols further combined to form esters, and various kinds of secondary decanols were oxidized to the corresponding ketones, suggesting that the substrate specifities of R. equi were not so restricted in isooctane.As to the the reaction conditions, water was positively required for the oxidation of higher alcohols such as 1-tetradecanol in organic solvents such as isooctane, although the amount of water required represented only a small portion of the reaction mixture.On the other hand, ester formation took place in isooctane practically free from water, and the rates of ester formation from 1-tetradecanol and tetradecanoic acid by dried cells increased with an increase in temperature up to 70 deg C in isooctane, while ester formation hardly occured at deg C when intact cells were used in place of dried cells.It was thus suggested that microbial ester formation is less susceptible to the thermal inactivation in the absence of water than in the presence.
- Ueda, Makoto,Mukataka, Sukekuni,Sato, Seigo,Takahashi, Joji
-
p. 1533 - 1538
(2007/10/02)
-
- Nucleophilic Addition to 4,5-Dihydroimidazoles: A Ketone Synthesis via Tetrahydrofolate Coenzyme Models
-
1-Benzyl-2-alkyl-3-methyl-4,5-dihydroimidazolium salts with Grignard reagents give addition products that are hydrolysed to ketones; 4,5-dihydroimidazoles and 4,5-dihydroimidazolium salts with hydride reagents afford N-alkylated ethane-1,2-diamines.
- Anderson, Michael W.,Jones, Raymond C.F.
-
p. 1995 - 1998
(2007/10/02)
-
- Reaction of Aldehyde O-Alkyl Oxime with Organometallic Compounds
-
Aldehyde O-alkyl oximes were converted into ketones with high yields when they were treated with alkyllithium compounds or Grignard reagents followed by hydrolysis.Amines as reductive alkylation products of aldehyde O-alkyl oximes were also obtained by BH3 reduction before hydrolysis.
- Itsuno, Shinichi,Miyazaki, Koji,Ito, Koichi
-
p. 3033 - 3036
(2007/10/02)
-
- Selective catalyzed-rearrangement of terminal epoxides to methyl ketones
-
Terminal epoxides of the type {A figure is presented} have been selectively converted into methyl ketones by various catalysts. Some lanthanide derivatives, MnI2, and Co2(CO)8 gave the best results. The rearrangement of internal epoxides into ketones is much slower, allowing specific transformation of terminal epoxides. The scope of the reaction and tentative mechanisms are discussed.
- Prandi,Namy,Menoret,Kagan
-
p. 449 - 460
(2007/10/02)
-
- α-Amino Carbanions. Preparation, Metalation, and Alkylation of Enamidines. Synthesis of Piperidine and Pyrrolidine Natural Products and Homologation of Carbonyl Compounds
-
Saturated heterocycles, as their tert-butylformamidines, may be transformed into enamidines, by metalation-selenation-elimination.These enamidines are valuable precursors to 2-substituted, 2,4-disubstituted, and 2,4,6-trisubstituted pyrrolidines, piperidines, and perhydroazepines, prepared in a regiospecific manner.The method is demonstrated by the synthsesis of selenopsin A and the red fire ant venom.The use of acyclic enamidines is displayed as a homologation reagent which converts carbonyl compounds to higher alkyl derivatives.
- Meyers, A. I.,Edwards, Philip D.,Bailey, Thomas R.,Jagdmann, G. Erik
-
p. 1019 - 1026
(2007/10/02)
-
- PALLADIUM CHLORIDE AND POLYETHYLENE GLYCOL PROMOTED OXIDATION OF TERMINAL AND INTERNAL OLEFINES
-
Both terminal and internal olefins can be efficiently converted to ketones in polyethylene glycol and water using palladium chloride as the catalyst.
- Alper, Howard,Januszkiewicz, Krysztof,Smith, David J. H.
-
p. 2263 - 2264
(2007/10/02)
-
- SILAFUNCTIONAL COMPOUNDS IN ORGANIC SYMTHESIS. 21. HYDROGEN PEROXIDE OXIDATION OF ALKENYL(ALKOXY)SILANES
-
The carbon-silicon bond in alkenyl(alkoxy)silanes is readily cleaved by hydrogen peroxyde to form the corresponding aldehydes, carboxylic acids or ketones, depending upon the nature of the alkenyl group and the reaction conditions.
- Tamao, Kohei,Kumada, Makoto,Maeda, Kimio
-
p. 321 - 324
(2007/10/02)
-
- REACTIVITE DES DERIVES ORGANOMANGANEUX-VIII; PREPARATION DE CETONES PAR ACYLATION D'ORGANOMANGANEUX. INFLUENCE DE LA NATURE DE L'AGENT ACYLANT, DES SOLVANTS ET DES LIGANDS
-
The influence of the nature of acylating reagents, solvents and ligands on the preparation of ketones by acylation of organomanganous reagents is studied.Thus acid chlorides in ether, symmetrical acid anhydrides in ether or THF and mixed carboxylic-carbonic anhydrides (R'COOCOOEt) in ether are compared, they lead to the corresponding ketones with good or excellent yields.Some problems of reproductibility are encountered and discussed when mixed anhydrides R'COOCOOEt are used in THF.The addition of a great variety of cosolvents (e.g.C6H6, AcOEt, CO3Et2, CH3CN, CH2Cl2...) to the reaction mixture before addition of the acylating reagent does not affect the yield of ketones.In comparison the complexation of organomanganous reagents by several ligands (e.g.Me2S or Ph3P) has no subsequent effect on their acylation.The main limitation for the choice of solvents or ligands is the use of amino derivatives which generally lead to a very low yield of ketones (e.g.C5H5N, TMEDA, Et3N) or unreproducible yields (e.g.HMPA).Two applications of these studies are described: -The stabilization of s or t-alkyl manganous derivatives by complexation which leads to the best yield of the corresponding ketones -The use of a cosolvent in order to increase the yield when mixed anhydrides R'COOCOOEt are used in THF.
- Friour, G.,Alexakis, A.,Cahiez, G.,Normant, J.
-
p. 683 - 694
(2007/10/02)
-
- SILAFUNCTIONAL COMPOUNDS IN ORGANIC SYNTHESIS. XVIII. OXIDATIVE CLEAVAGE OF THE SILICON-CARBON BOND IN ALKENYLFLUOROSILANES TO CARBONYL COMPOUNDS: SYNTHETIC AND MECHANISTIC ASPECTS
-
Alkenyltrifluorosilanes are readily oxidized by one equivalent of MCPBA in DMF even at -50 deg C to give the corresponding carbonyl compounds via cleavage of the carbon-silicon bond.With three equivalent of MCPBA a concomitant cleavage of the carbon-carbon bond occurs.A plausible mechanism of these new types of oxidation has been discussed.Oxidation with DABCO*2H2O2 has also been described.
- Tamao, Kohei,Akita, Munetaka,Kumada, Makoto
-
-
- 1-BROMO-1-(TRIMETHYLSILYL)-1-ALKENES. A SINGLE SYNTHON FOR BOTH THE CARBONYL ANION AND CATION
-
The utility of 1-bromo-1-(trimethylsilyl)-1-alkenes as a single synthon for both the carbonyl anion and cation is demonstrated.
- Miller, R. B.,Al-Hassan, M. I.,McGarvey, G.
-
p. 969 - 976
(2007/10/02)
-
- THE PREPARATION OF KETONES WITH 1-PHENYLTHIO-1-TRIMETHYLSILYLETHENE
-
The ketone equivalents (3) were prepared by the addition of an alkyllithium to 1-phenylthio-1-trimethylsilylmethane (1) followed by reaction with an alkyl halide.
- Ager, David J.
-
-
- Reactions of Primary Amines with Organolithium Compounds
-
Primary amines react under mild conditions with an excess of an organolithium compound to form imines and α-substituted primary amines.Frequently, N-alkylamines that result from the condensation of these products are also isolated.For example, reactions of PhCH2NH2 with RLi (R = n-Bu) in refluxing hexane furnish (after hydrolysis) PhCHRNH2, PhRC=O, PhRC=NCHRPh, and R2C=O.The organic group of the primary amine can be a primary, secondary, or tertiary alkyl group.A reaction scheme is proposed that has three types of steps: (1) Mono- and dilithiation of the primary ami ne by an organolithium compound (both lithiations generally at nitrogen). (2) Elimination from the mono- or dilithiated amine of lithium hydride or (when the alkyl group is tertiary) of the elements of an organolithium compound to produce an N-lithioimine. (3) Addition of an organolithium compound to the lithioimine to produce a new dilithiated amine.The scheme rationalizes both the structures of the products and the effects of reaction conditions on product composition.Reaction of benzonitrile with an excess of n-butyllithium furnishes (after hydrolysis) di-n-butyl ketone as the major product.Since this reaction must also proceed through an N-lithioimine, formation of this product provides additional evidence for the proposed addition and elimination steps.
- Richey, Herman G.,Erickson, Wayne F.
-
p. 4349 - 4357
(2007/10/02)
-
- Nucleophilic Addition to 2-Imidazolines. A Ketone Synthesis via Tetrahydrofolate Coenzyme Models
-
2-Alkyl-1-benzyl-3-methyl-2-imidazolinium salts with Grignard reagents give addition products that are hydrolysed to ketones; 2-imidazolines and 2-imidazolinium salts with hydride reagents afford N-alkylated 1,2-diaminoethanes.
- Anderson, Michael W.,Jones, Raymond C. F.,Saunders, John
-
p. 282 - 283
(2007/10/02)
-
- Silyl Halides from (Phenylseleno)silanes. Reaction with Oxiranes and Alcohols To Give Hydrolytically Stable Silyl Ethers.
-
The preparation of (phenylseleno)silanes and their reactions with halogens (Cl2, Br2, I2) to give silyl halides and diphenyl diselenide are described.Highly hindered tert-butyldimethyl and tert-butyl diphenylsilyl halides were easily prepared.The reaction of silyl bromides and iodides with oxiranes followed by diazabicyclononane treatment gave allylic alcohol silyl ethers.Tertiary alcohols reacted rapidly with silyliodides to give hydrolytically stable silyl ethers.Treatment of the silyl ethers with tetra-n-butylammonium fluoride gave the free alcohols withoutrearrangement or isomerization.
- Detty, Michael R.,Seidler, Mark D.
-
p. 1283 - 1292
(2007/10/02)
-
- Electrophilic Conversion of Oxiranes to Allylic Alcohols with tert-Butyldimethylsilyl Iodide
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tert-Butyldimethylsilyl iodide (I) is prepared from the reaction of iodine with (phenylseleno)-tert-butyldimethylsilane in acetonitrile.The reaction of oxiranes with 1 followed by treatment with 1,5-diazabicyclonon-5-ene gives accetable yields of allylic alcohols isolated as their tert-butyldimethylsilyl ethers.Ring opening involves cleavage of the bond to the more highly substituted carbon.
- Detty, Michael R.
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p. 924 - 926
(2007/10/02)
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