Alkenes ethyl acetate

Lindlar catalyst can be used for hydrogenation of l-[3-(2-phenylpyrazolo[1.5-a]pyridin-3-yl)propynoyl]-2-ethylpiperidine in ethyl acetate (38%) (Scheme 82 89EUP299209 92USP5102869) and l-(hetaryl)-4-alkynylpyrazole derivatives to the corresponding alkenes (96EUP703234). 

Replacement of silver nitrite by inexpensive sodiiunor potassium nitrite enhances the imlity of this process Treatment of alkenes v/ith sodiiun nitrite and iodine in ethyl acetate and water in the presence of ethylene glycol gives conjngatednitroalkenesin49-82% yield The method for generation of nitryl iodide is improved by the treatment of iodme v/ith potassium nitrite complexed v/ith 18-crovm-6 in THF under sonicadon, as shovmin Eq 2 32 ... 

Ruthenium tetroxide can also be used in the oxidation of alkenes. Conditions that are selective for formation of ketols have been developed.36 Use of 1 mol % of RuC13 and five equivalents of KHS05 (Oxone ) in an ethyl acetate-acetonitrile-water mixture gives mainly hydroxymethyl ketones from terminal alkenes. 

The first step of the reaction is likely to be the protonation of ethylene to produce a carbocation that undergoes the direct addition of acetic acid to produce ethyl acetate. The successive addition of ethylene to the carbocation leading to the production of alkene oligomers is a likely side reaction Formation and accumulation of these oligomers could eventually deactivate the catalyst. Detailed studies for a better understanding of the complex reaction mechanism are in progress. 

The asymmetric hydroformylation of functionalized aliphatic alkenes is generally more difficult than the hydroformylation of vinyl arenes. The rhodium-catalyzed hydroformylation of vinyl acetate (36) yields 2- and 3-acetoxypropanals, 37 and 38, with high chemoselectivity. Ethyl acetate and acetic acid can also be found as by-products. One of the potential applications of vinyl acetate hydroformylation is the production of enantiopure propane 1,2-diol (Scheme 6). 

Solvents exert control on the chemose-lective hydrogenation of alkenes bearing a benzyloxy protecting group [160]. In the unpolar solvent benzene, only the double bond is hydrogenated, while in methanol, acetone, and ethyl acetate, the benzyloxy group is also removed. Selective... 

By far the most commonly used - though not the most environmentally friendly -solvent is CCl (or more usually water-CCl ). In a classic paper Sharpless et al. showed that oxidation reactions of RuO (and other some Ru-based oxidants) were accelerated by addition of a little acetonitrile to the conventional water-CCl biphasic mixture. It was suggested that the CH3CN might function as a mild donor stabilising a lower oxidation state carboxylato Ru species which could be involved in the catalytic process [260]. A comparative study of CCl, acetone, ethyl acetate, cyclohexane and acetone for cleavage of alkenes and alkynes by RuClg/aq. IO(OH)3/solvent showed that cyclohexane was the most effective [216]. Other solvents sometimes... 

O 16.14% crysts (from acet, benz or ethyl acetate), mp 206.5-07.5° 214.5-15.5°, de-pending on cryst size, rate of heating solv used fairly sol in hot benz CCI4 diffc sol in eth, acet, eth acet acet ac insol in ale was obtd by ozonolysis of 1,1-diphenyl-l-alkenes In CCI4 and hydrolysis of the ozonide No expin of this compd occurred when heated to its mp, but when heated for 5 mins at 214-15°, it decompd comjietely to benzo-phenone... 

To a stirred solution of samarium diiodide (1.5 mmol) in THF (12 ml) was rapidly added a solution of a (3-hydroxy sulfone (0.5 mmol) in THF (6 ml) under an argon atmosphere. After 15 min at room temperature the reaction mixture was still blue, due to an excess of Sml2. The reaction mixture was then poured into a 10% solution of Na2S203 (20ml) and extracted with ethyl acetate. The residue was chromatographed over silica gel (hexane/ethyl acetate 99 1) to give the alkene (55-82%) as a mixture of ( )/(Z) isomers. 

The catalyst The amount of catalyst required in an aryl bromide or iodide alkene substitution varies widely with the reactants and the reaction conditions. Most examples reported have used 1-2 mol % of palladium salt relative to the aryl halide, but much lower amounts are sufficient in some instances. In an extreme case, where very reactive p-nitrobromobenzene was added to the very active alkene, ethyl acrylate and sodium acetate was the base in DMF solution at 130 C with a palladium acetate-tri-o-tolylphos-phine catalyst in 6 h the palladium turned over 134 000 times and ethyl p-nitrocinnamate was obtained in 67% yield.63... 

Method A. A solution of CTAP (2.02 g, 5 mmol) in dichloromethane (30 ml) is added dropwise to a stirred solution of the alkene (5 mmol) in dichloromethane (15 ml) at 20 °C. Stirring is continued for 1-5 hours and the mixture then concentrated to half its volume under reduced pressure. The residual solution is diluted with ether (50 ml) and filtered through a pad of Celite and magnesium sulphate. The filtrate is evaporated under reduced pressure and the remaining w c-diol purified by recrystallisation from ethyl acetate/light petroleum. 

It has been shown that toxic carbon tetrachloride can be replaced by ethyl acetate in the ruthenium-catalysed oxidation of alkenes and monoenic fatty acids. Oxidative... 

A solution or suspension of the acid (1 mmol) in carbon tetrachloride (75 ml) containing DIB (0.55 mmol) and iodine (0.5 mmol) was irradiated with two 100 W tungsten-filament lamps for 45 min at reflux temperature. Another portion of DIB (0.55 mmol) was then added and irradiation was continued for 45 min at reflux. The reaction mixture was washed with dilute sodium thiosulphate and water, concentrated and chromatographed (silica gel column, 9 1 hexanes-ethyl acetate) to afford the alkyl iodide. Several steroidal acids with the carboxyl group attached at a 1° or 2° carbon atom gave the corresponding iodides in good yields. Acids with a 3° a-C instead of the iodide afforded alkenes similarly, alkenes were formed with a fivefold excess of DIB in the presence of cupric acetate. Aromatic acids also underwent iododecarboxylation, in moderate yields very effective was the otherwise difficult transformation of 1,8-naphthalenedicarboxylic acid to 1,8-diiodonaphthalene (80%) [68]. Cubyl and homocubyl iodides were also prepared in excellent yield [69]. 

QCdmJpFJ [QCpmJBr PdCl2 Pd(OAc)2 NaOAc 30 °C. Ligand-free, ultrasound promoted arylation of alkenes and alkynes with aryliodides palladium bis-carbenes and palladium nanoparticles ( 1 nm) are identified after catalysis product extracted with ethyl acetate/petrol ether. [66]... 

A typical procedure for Eq. (78) [153] is as follows. In a 100-ml two-necked flask with a reflux condenser, a balloon, and a rubber cap are placed Pd(OAc)2 (0.05 mmol), Cu(OAc)2 H2O (0.05 mmol), and molecular sieves 4 A (400 mg). After the apparatus is evacuated by pumping, nitrogen (750 ml) is introduced. Then the phenol (1 mmol), the alkene (3 mmol), DMF (5 ml), and air (150 ml) are injected into the flask, and the resulting mixture is stirred at 100 °C for 9 h. After cooling, the mixture is extracted with diethyl ether and dried over sodium sulfate. The coupling product is isolated by column chromatography on silica gel using hexane-ethyl acetate (99.5 0.5, v/v) as eluent. 

Diphenyl carbonate from dimethyl carbonate and phenol Dibutyl phthalate from butanol and phthalic acid Ethyl acetate from ethanol and butyl acetate Recovery of acetic acid and methanol from methyl acetate by-product of vinyl acetate production Nylon 6,6 prepolymer from adipic acid and hexamethylenediamine MTBE from isobutene and methanol TAME from pentenes and methanol Separation of close boiling 3- and 4-picoline by complexation with organic acids Separation of close-boiling meta and para xylenes by formation of tert-butyl meta-xyxlene Cumene from propylene and benzene General process for the alkylation of aromatics with olefins Production of specific higher and lower alkenes from butenes... 

The cleavage reaction, commonly referred to as ozonolysis , is carried out by bubbling ozonized oxygen through a solution of the alkene in various solvents, including methanol, dichloromethane, carbon tetrachloride and ethyl acetate. Other solvents (ethanol, tetrahydrofiiran, acetic acid, or a combination of ethyl acetate and hexane) have also been reported for use in individual reactions.The reaction is usu ly performed at low temperatures (about 0 C), and, since ozonides are potentially explosive compounds, the intermediates are not isolated. 

The conversion of alkenes to oxiranes using ketone catalysts in the presence of a terminal oxidant such as Oxone has proved to be an important advance in the past decade, especially for the formation of chiral oxiranes (see Section 1.03.4.3.3(ii)). The conversion of alkenes to oxiranes has been comprehensively reviewed <20020R219>. The formation of the dioxirane species usually proceeds in situ, whether it be the formation of methyl(trifluoromethyl)-dioxirane in an academic setting <1995JOC3887>, or under conditions amenable to large-scale conversion of aromatic alkenes to oxiranes (oxone, acetone, ethyl acetate, no phase-transfer catalysis) <20020PD405>. 

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