- Hydration of terminal alkynes catalyzed by water-soluble cobalt porphyrin complexes
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Water-soluble cobalt(III) porphyrin complexes were found to promote the hydration of terminal alkynes to give methyl ketones. The alkyne hydration proceeded in good to excellent yield with 0.1 to 2 mol % cobalt catalyst 1 and was compatible with the presence of acid/base- or redox-sensitive functional groups such as alkyl silyl ethers; allyl ethers; trityl ethers; benzyl ethers; carboxylic esters; boronic esters; carboxamides; nitriles; and nitro, iodo, and acetal groups. Some of the alkyne substrates tested here are otherwise difficult to hydrate. The alkyne hydration can be performed on a gram scale, and the catalyst can be recovered by aqueous workup.
- Tachinami, Tadashi,Nishimura, Takuho,Ushimaru, Richiro,Noyori, Ryoji,Naka, Hiroshi
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supporting information
p. 50 - 53
(2013/02/23)
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- Controlling the photochemical reactions of alkenes by light-path length effects of a microchannel reactor
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Photoirradiation of Me2CO-H2O solution of pent-4-en-1-ol (1a) with a high-pressure mercury lamp in a test tube gave 8-hydroxyoctan-2-one (3a) in 66 % yield along with oxetane (4a) and the isomer (4a') in 10 % yield. Irradiation of the running Me2CO-H2O solution of 1a in the flow system of a microchannel reactor (MCR) gave mainly 4a. The photoreaction of 1,1-diphenylethene (2a) with triethylamine gave a Markovnikov-type adduct (5a) and an anti-Markovnikov-type adduct (6a). The use of the MCR enhanced the production of 5a. These phenomena were explained by the light-path length effects of the MCR.
- Yamashita, Toshiaki,Matsushita, Shuhei,Nagatomo, Takuya,Yamauchi, Ryosuke,Yasuda, Masahide
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p. 111 - 126
(2013/02/25)
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- Iridium complex-catalyzed addition of water and alcohols to non-activated terminal alkynes
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The addition of water and alcohols to non-activated terminal alkynes was found to be promoted by an iridium complex combined with Lewis acid and phosphite. Thus, terminal alkynes reacted with water or alcohols to give ketones or ketals, respectively, in good to excellent yields. α,ω-Diyne like 1,7-octadiyne was converted into 1-(2-methyl-cyclopent-1-enyl)ethanone through the intramoleculer aldol condensation of the resulting 2,7-octanedione induced by Lewis acid.
- Hirabayashi, Tomotaka,Okimoto, Yoshio,Saito, Akiyo,Morita, Masao,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 2231 - 2234
(2007/10/03)
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- Process for producing carbonyl compound
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The present invention relates to a process which comprises efficiently proceeding a hydration reaction of an alkyne in aspects of turnover numbers of a catalyst, yield and speed to thereby industrially and advantageously produce the corresponding carbonyl compound. The present invention provides a process for producing a carbonyl compound, which comprises reacting an alkyne compound with water in the presence of a gold catalyst which is an organogold complex compound and acid in an organic solvent.
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Page/Page column 8
(2008/06/13)
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- Indium(I) bromide-mediated regioselective Markovnikov hydroselenation, diselenation and hydration of terminal alkynes with diphenyldiselenide in aqueous media
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The indium(III) selenolate obtained from indium(I) bromide and diphenyldiselenide promotes, alternatively, the Markovnikov hydroselenation, diselenation or hydration of terminal alkynes, depending on the experimental conditions. Georg Thieme Verlag Stuttgart.
- Peppe, Clovis,Lang, Ernesto Schulz,Ledesma, Gabriela Nanci,De Castro, Liérson Borges,Barros, Olga Soares Do Rego,De Azevedo Mello, Paola
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p. 3091 - 3094
(2007/10/03)
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- New ketone homoenolate anion equivalents derived from (alkenyl)pentamethyl phosphoric triamides
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Lithiated ambident anions derived from (1-alkyl-2-propenyl)- or (1-phenyl-2-propenyl)-pentamethyl phosphoric triamides undergo regioselectively γ-reaction with various alkylating reagents and isobutyraldehyde. Further hydrolysis of adducts releases the ketone under acid conditions. Number of synthetic applications clearly show the ketone homoenolate behaviour of these new carbanions.
- Grison, Claude,Thomas, Antoine,Coutrot, Frédéric,Coutrot, Philippe
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p. 2101 - 2123
(2007/10/03)
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- Reactions of Grignard reagents with bis- or mono-phosphonium ions in Situ generated from Bu3P and dicarboxylic acid dichlorides or ω-ethoxycarbonyl alkanoyl chlorides as a novel method to obtain diketones and ketoesters
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Reactions of Grignard reagents with bis-phosphonium or mono-phosphonium ions in situ generated from Bu3P and ClCO(CH2)(n)COCl (5) or ClCO(CH2)(n)CO2Et (13) as a tool for preparation of symmetrical diketones or ketoesters were examined. Addition of Bu3P (2.0 eq) to a THF solution of 5 (n=2) at -40°C followed by addition of n-BuMgCl (2.0 eq) gave the corresponding diketone in good yield. When a mixture of Bu3P and the Grignard reagent (2.0 eq each) was added to the dichloride solution at the same temperature, a better result was obtained. The latter method not with PhMgBr but with n-BuMgCl or MeMgBr was shown to be useful for preparation of symmetrical alkanediones and keto alkanoates from various 5 (n=2 - 6) and 13 (n=2 or 3), respectively. For synthesis of α-diketones or α-ketoesters, only PhMgBr entered the reaction, although the yields were not satisfactory. Addition of a mixture of Bu3P (2.0 eq), MeMgBr (1.0 eq) and BuMgCl (1.0 eq) to a THF solution of 5 (n=4) at -40°C afforded a mixture of 2,7-undecanedione and the corresponding two symmetrical diketones, with the yield of the unsymmetrical diketone being 36%.
- Maeda,Hino,Yamauchi,Ohmori
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p. 1196 - 1199
(2007/10/03)
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- Thermostable Enzymes in Organic Synthesis. 7. Total Synthesis of the Western Corn Rootworm Sex Pheromone 8-Methyldec-2-yl Propanoate Using a TBADH-Generated C2-Bifunctional Chiron
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Enantiomerically pure alcohols produced by Thermoanaerobium brockii alcohol dehydrogenase (TBADH)-catalyzed asymmetric reduction of polyfunctional ketones are useful building blocks for natural products synthesis.This advantage has been demonstrated by a total synthesis of all four isomers of 8-methyldec-2-yl propanoate, the sex pheromone emitted by the female western corn rootworm, Diabrotica virgifera virgifera LeConte.These four isomers were obtained in a very short procedure (either three or five steps) with an enantiomeric purity that exceeds 99 percent using a single chiral building block, (2S,8S)-(+)-2,8-dihydroxynonane.The latter diol, characterized by a synthetically useful C2 symmetry, was obtained by TBADH-catalyzed reduction of nonane-2,8-dione.
- Keinan, Ehud,Sinha, Subhash C.,Sinha-Bagchi, Anjana
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p. 3631 - 3636
(2007/10/02)
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- A Convenient Synthesis of Diketones via Alkylation of Alkyl Methyl Ketone Dimethylhydrazones
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Symmetrical diketones were prepared by the reaction of the lithium salts of alkyl methyl metone dimethylhydrazones with dibromoalkanes.
- Yamashita, Masakazu,Matsumiya, Kaoru,Morimoto, Hiroko,Suemitsu, Rikisaku
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p. 1668 - 1670
(2007/10/02)
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- Synthesis and Application of Imidazole Derivatives: Preparation of Various Diketones from 1,n-Bis(1-methyl-1H-imidazol-2-yl)alkane-1,n-diones
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Reaction of 1,n-bis(1-methyl-1H-imidazol-2-yl)alkane-1,n-dione (8) with an excess of Grignard reagent was examined.In the cases of n = 4 and 5, precursors (14) for synthesis of various asymmtric 1,4- and 1,5-diketones (12: R1 R2), respectively, were obtained in good yields by treating 8 with an excess of methylmagnesium iodide in ether followed by trimethylsilylation.In the case of n >/= 8, the two carbonyl groups of 8 were both attacked by the Grignard reagent, and the products (11: R1=R2=CH3) were convertible to symmetrical diketones (12: R1=R2=CH3) in good yields.In cases of n = 6 and 7, the mode of the Grignard reaction was transitional between the two types.Keywords - 2-acyl-1H-imidazole; 1,n-bis(1-methyl-1H-imidazol-2-yl)-1,n-alkanedione; diketone synthesis; asymmetric diketone; symmetric diketone; Grignard reaction; dihydrojasmone; cis-jasmone; muscone; 2-(1-hydroxy-1-alkyl)-1-methyl-1H-imidazole
- Hayakawa, Satoshi,Baba, Junko,Okamoto, Masao,Ohta, Shunsaku
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- A Convenient Synthesis of Acyclic 1,n-Diketones (n=5-8) from 2-t-Butylperoxycycloalkanones
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The reaction of organolithium with 2-alkyl-2-t-butylperoxycycloalkanones, readily available from t-butylperoxylation of 2-alkylcycloalkanones, gave 2-t-butylperoxy-1-cycloalkanol derivatives quantitatively, thermal decomposition of which with or without an acid afforded 1,n-diketones (n=5-8) in excellent yields.
- Nishinaga, Akira,Rindo, Katsuhiko,Matsuura, Teruo
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p. 1038 - 1041
(2007/10/02)
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- Lithiation of Alkoxyalkyl Phenyl Sulfones. New Approach to Acyl Anion Synthesis
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(1-Ethoxyethoxy)methyl and (1-ethoxyethoxy)ethyl phenyl sulfones undergo metalation with LDA in THF in the presence of HMPA.The resulting lithium salts were easily alkylated with various alkyl halides and hydrolyzed under mild conditions to give the corresponding carbonyl compounds.The new synthetic method for the preparation of aldehydes and ketones employing these carbanions has been developed.
- Tanaka, Kazuhiko,Matsui, Syuichi,Kaji, Aritsune
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p. 3619 - 3622
(2007/10/02)
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