- Chemo-, regio-, and stereoselective synthesis of syn -aryl glycol monoesters from aryl olefins with hydrogen peroxide catalyzed by RuCl 3
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Chemo-, regio-, and stereoselectivity have been achieved in the oxidations of aryl olefins. The aryl olefins were oxidized by 2 equivalents of H 2O2 in acetic acid, catalyzed by 0.02 equivalent of RuCl3, leading to the formations of syn-aryl glycol monoesters. As the reaction is concerted, both the regio- and stereoselectivity are excellent. In the presence of aliphatic C=C bonds, the aryl C=C bonds were selectively dioxygenated. This represents the first example of chemoselective dioxygenation of aryl C=C bonds. Georg Thieme Verlag Stuttgart - New York.
- Zhang, Yanqiao,Chu, Guobiao,Cui, Xiaoxue,Han, Zhijie,Dou, Daoke,Chen, Yuanli,Yu, Xiaosong,Li, Chunbao
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supporting information; experimental part
p. 1118 - 1122
(2010/06/20)
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- Bis(NHC)-palladium(II) complex-catalyzed dioxygenation of alkenes
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Bis(NHC)-Pd(II) complexes derived from l,l'-binaphthyl-2,2'-diamine (BINAM) were successfully first used to catalyze the dioxygenation of alkenes under mild conditions tolerant of air and moisture. Cationic NHC-Pd2+ diaquo complex 1e showed the highest catalytic activity to give 1,2dioxygenation products with good syn-diastereoselectivity for 1,2-disubstituted alkenes.
- Wang, Wenfeng,Wang, Feijun,Shi, Min
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experimental part
p. 928 - 933
(2010/05/01)
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- A rapid 1,2-dihydroxylation of alkenes using a lipase and hydrogen peroxide under microwave conditions
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The combined advantages of using an enzyme immobilized lipase from Pseudomonas sp [PSLG6], hydrogen peroxide, ethyl acetate and microwave irradiation for the dihydroxylation of olefins are reported.
- Sarma, Kuladip,Borthakur, Naleen,Goswami, Amrit
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p. 6776 - 6778
(2008/02/13)
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- Alkylchlorotins grafted to cross-linked polystyrene beads by a -(CH 2)n spacer (n-4, 6, 11): Selective, clean and recyclable catalysts for transesterification reactions
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Insoluble polystyrene grafted compounds of the type (P-H) (1-t)(P-(CH2)nSnBupCl 3-p,}t, (P-H)(1-t){P-(CH2) nSnBuO)t and (P-H)(1-t)[(P-(CH 2)nSnBuCl}2O]t/2, in which (P-H) is a cross-linked polystyrene; n=4, 6, and 11; p=0 and 1; and t the degree of functionalisation, were synthesised from Amberlite XE-305, a polystyrene cross-linked with divinylbenzene. The compounds were characterised by using elemental analysis, and IR, Raman, solid-state 117Sn NMR, and 1H and 119Sn high-resolution MAS NMR spectroscopy. The influence of the spacer length and the tin functionality on the catalytic activity of these compounds, as well as their recycling ability, was assessed in the transesterifica tion reaction of ethyl acetate with various alcohols. These studies showed significant differences in the activity of the catalysts interpreted in terms of changes in the mobility of the catalytic centres. Some of the supported catalysts could be recycled at least seven times without noticeable loss of activity. The residual tin content in the reaction products was found to be as low as 3 ppm.
- Camacho-Camacho, Carlos,Biesemans, Monique,Van Poeck, Manu,Mercier, Frederic A. G.,Willem, Rudolph,Darriet-Jambert, Karine,Jousseaume, Bernard,Toupance, Thierry,Schneider, Uwe,Gerigk, Ursula
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p. 2455 - 2461
(2007/10/03)
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- Dialkyl peroxides decomposition in the presence of quaternary ammonium halides
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Decomposition of dicumyl peroxide and cumyl tert-butyl peroxide was studied in the presence of tetraethylammonium halides in acetonitrile, dimethylformamide, 2-propanol, and acetic acid. The tetraethylammonium halides accelerate the decomposition of dialkyl peroxides in 2-propanol and acetic acid, but do not affect the reaction velocity in dimethylformamide and acetonitrile. The decomposition products character depends on the solvent nature.
- Maksyuta,Suprun,Opeida,Turovskii
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p. 814 - 818
(2007/10/03)
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- A convenient synthesis of 2-phenylglycerol
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1,3-Dihydroxyacetone dimer is treated with trimethylsilyl chloride and triethylamine in dichloromethane to provide monomeric ketone having both of its alcohols protected as their di-TMS ethers. The latter is added to phenylmagnesium bromide in ether at -78°C. Work-up by treatment with aqueous ammonium chloride followed by 2 N HCl provides 2-phenylglycerol in 70% yield.
- Klis,Erhardt
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p. 4027 - 4038
(2007/10/03)
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- Thermolysis of substituted tert-butyl-(2-phenyl-prop-2-yl) peroxides
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tert-Butyl-(2-phenyl-1-methoxy-prop-2-yl)-peroxide (1a), tert-butyl-(2-phenyl-1-acetoxy-prop-2-yl)-peroxide (1b) and tert-butyl-(1,2-diphenyl-prop-2-yl)-peroxide (1c) were prepared from t-BuOOH and 1-methoxy-2-phenyl-prop-2-ol (a), 2-phenyl-2-methyl-oxirane (b) and, respectively, 1,2-diphenyl-propan-2-ol (c). The peroxides 1a-c were characterized by NMR spectroscopy and elemental analysis. Kinetic data were determined and the products analyzed from thermolysis of 1a-c at 110-155°C in cumene as the solvent. The major thermolysis product from 1a-c was acetophenone, formed via fragmentation of intermediate alkoxy radicals: R-CH2-C(Ph)(Me)O (R: MeO (a); AcO (b); Ph (c)). Wiley-VCH Verlag GmbH, 1999.
- Suprun
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p. 363 - 368
(2007/10/03)
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- Lipase-catalyzed hydrolysis of some racemic 1-acetoxy-2-arylpropanes
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Racemic 1-acetoxy-2-phenylpropane (12) and 1-acetoxy-2-(2- naphthyl)propane (33) were hydrolyzed with lipase at 35-36°C for 2 and 24 h to give predominantly (S)-2-phenyl-1-propanol (11) and (S)-2-(2-naphthyl)-1- propanol (32), respectively. However, racemic 1-acetoxy-2-(1-naphthyl)propane (25) was recovered intact even when the reaction was carried out for 240 h. On the other hand, the enantioselectivities towards racemic 2-phenyl (16), 2- (p-tolyl) (20), 2-(1-naphthyl) (28), and 2-(2-naphthyl) (36) derivatives of 1-acetoxy-2-propanol were very low.
- Matsumoto,Takeda,Iwata,Sakamoto,Ishida
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p. 1191 - 1197
(2007/10/02)
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- THER RECATION OF α-METHYLSTYRENE ANALOGS AND RELATED COMPOUNDS WITH SODIUM PERBORATE IN ACETIC ACID
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A series of α-substituted styrene analogs have been reacted with sodium perborate in acetic acid to produce 1-acetoxy-2-aryl-2-popanol analogs in good yield.The reaction constitutes a mild and convenient method for the oxidation of styrene type double bon
- Gupton, John T.,Duranceau, Steven J.,Miller, John F.,Kosiba, Michael L.
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p. 937 - 948
(2007/10/02)
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- OXIDATION BY COBALT(III) ACETATE. PART 6. A NOVEL SYNTHESIS OF THE GLYCOL MONOACETATES FROM AROMATIC OLEFINS IN WET ACETIC ACID
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Oxidation of various aryl-conjugated olefins with cobalt(III) acetate in wet acetic acid under nitrogen affords the glycol monoacetates in moderate to good yields.None of the phenyl rearrangement product is formed in the present reactions.These results are best interpreted by assuming the formation of a Co-co-ordinated intermediate.
- Hirano, Masao,Morimoto, Takashi
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p. 1033 - 1036
(2007/10/02)
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- Preparation and Reactivities of Hexakisacetonitrile Iron(III) Perchlorate and Related Complexes as Strong Oxidizing Reagents
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The iron(III) complexes Fe(S)6(ClO4)3, S=solvent, were prepared from Fe(H2O)6(ClO4)3 in the donor solvents.Reactions of alkylbenzenes with Fe(AN)6(ClO4)3 (AN=acetonitrile) were explored because the AN complex has the highest formal redox potential, E0=1.73 V vs.SCE, among these complexes.Oxidation of the primary alkylbenzenes by the iron(III) AN complex gave the corresponding acetamides (Table II).Oxidation of the secondary alkylbenzenes, namely, cumene, 2-phenylbutane, and 2-exo-phenylnorbornane, afforded the corresponding acetates and acetamides (Charts 2 and 3), consuming over 4-mol eq of reagent.Reactions of p-xylene and hexamethylbenzene with Fe(CH2=CHCN)6(ClO4)3 also yielded the amides 31a and 31b.These results demonstrate the applicability of the iron(III) AN complexes as a powerful reagent to oxidize organic substrates which have onset potentials of anodic current of ca. 2.0 V vs.SCE.Keywords - oxidation; primary alkylbenzene; secondary alkylbenzene; oxidizing reagent; iron(III) perchlorate solvate; hexakisacetonitrile iron(III) perchlorate; hexakisacrylonitrile iron(III) perchlorate
- Kotani,Eiichi,Kobayashi, Shigeki,Ishii, Yoko,Tobinaga, Seisho
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p. 4281 - 4291
(2007/10/02)
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- Electron-transfer Processes: Oxidation of α- and β-Alkenylbenzenes by Peroxydisulphate in Acetic Acid
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Oxidation of α- and β-unsaturated alkylbenzenes by peroxydisulphate in acetic acid gives side-chain acetoxylation with formation of the corresponding glycol diacetates and compounds (10), respectively.The reaction is catalysed by transition-metal salts, among which cupric acetate gives the best results.Generally, electron-releasing substituents on the benzene ring increase the yield and improve the selectivity.The same substrates are oxidized in water under Ag+ catalysis to the corresponding aldehydes.The different behaviour in the two solvents is ascribed to the difference in reactivity between the primary oxidation products and the starting olefin, whereas the initial oxidation step is suggested to occur in both cases via an electron-transfer process from the olefin to the sulphate radical anion.
- Citterio, Attilio,Arnoldi, Claudio,Giordano, Claudio,Castaldi, Grasiano
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p. 891 - 896
(2007/10/02)
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