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The synthesis of ethers from alcohols and aldehydes or ketones via the corresponding hemiketals is reported using Pd/C as catalyst, under hydrogen. Good isolated yield (> 80%) are obtained.

A general protocol for the selective hydrogenation and deuteration of a variety of alkenes is presented. Key to success for these reactions is the use of a specific nickel-graphitic shell-based core–shell-structured catalyst, which is conveniently prepared by impregnation and subsequent calcination of nickel nitrate on carbon at 450 °C under argon. Applying this nanostructured catalyst, both terminal and internal alkenes, which are of industrial and commercial importance, were selectively hydrogenated and deuterated at ambient conditions (room temperature, using 1 bar hydrogen or 1 bar deuterium), giving access to the corresponding alkanes and deuterium-labeled alkanes in good to excellent yields. The synthetic utility and practicability of this Ni-based hydrogenation protocol is demonstrated by gram-scale reactions as well as efficient catalyst recycling experiments.

The Co2(CO)8-catalyzed reaction of acetals with hydrosilanes and CO under mild reaction conditions (an ambient temperature under an ambient CO pressure), leading to the production of vicinal diols is reported. A siloxymethyl group can be introduced via the cleavage of one of two alkoxy groups in the acetal. The effects of the types of hydrosilanes, acetals, solvents, and reaction temperatures on the yield of siloxymethylation products were examined in detail. The reactivity for hydrosilanes is as follows; HSiMe3 > HSiEtMe2 > HSiEt2Me > HSiEt3. Hemiacetal esters are more reactive than dimethyl acetals. The polarity of the solvent used also has a significant effect on both the course of the reaction as well as the reaction rate. The site-selective siloxymethylation can be achieved in the case of cyclic acetals such as tetrahydrofuran (THF) and tetrahydropyrane (THP) derivatives, depending on the nature of the oxygen substituent attached adjacent to the oxygen atom in the ring. When 2-alkoxy THF or THP derivatives are used as substrates, the siloxymethylation takes place with cleavage of the ring C-O bond. In contrast, the reaction of 2-acetoxy THF or THP derivatives results in siloxymethylation with the cleavage of C-OAc bond. The ring-opening siloxymethylation of lactones was also examined.

The alkylation of alcohols and polyols has been investigated with alkylphosphates in the presence of a Lewis or Br?nsted acid catalyst. The permethylation of polyols was developed under solvent-free conditions at 100 °C with either iron triflate or Aquivion PW98, affording the isolated products in yields between 52 and 95 %. The methodology was also adjusted to carry out peralkylation with longer alkyl chains.

Herein we report that a single frustrated Lewis pair (FLP) catalyst can promote the reductive etherification of aldehydes and ketones. The reaction does not require an exogenous acid catalyst, but the combined action of FLP on H2, R-OH or H2O generates the required Br?nsted acid in a reversible, “turn on” manner. The method is not only a complementary metal-free reductive etherification, but also a niche procedure for ethers that would be either synthetically inconvenient or even intractable to access by alternative synthetic protocols.

The synthesis of methylated ether compounds is an important challenge. A pathway for the synthesis of methyl ethers was investigated using dimethyl sulfite (DMSi). Methylation of 1-octanol was carried out in liquid phase upon different heterogeneous organic and inorganic catalysts at 130°C. Aluminium oxide gave the best result with high conversion and moderate selectivity for methyl 1-octyl ether. Reactions in gas phase at higher temperatures (200°C) were also performed. Methyl 1-octyl ether was obtained in a very high level of selectivity up to 98%. Primary and secondary ethers from unsymmetrical alkyl methyl sulfite were also performed by SO2 extrusion.

A bio-derived protecting/activating group has been synthesized by introducing a sulphonyl chloride group to the aromatic ring of p-cymene derived from citrus peel waste. The resulting p-cymenesulphonyl chloride was evaluated as an activating group by reacting with 1-octanol, 2-octanol, phenol and piperidine, and further reactions of the activated alcohols. The comparison to tosyl chloride demonstrates that the bio-based alternative can be effectively utilized as a direct replacement for the current fossil derived equivalent.

Aluminium trichloride catalyses the expeditious direct conversion of tetrahydropyranyl ethers to silyl ethers. This one-step transformation is chemoselective versus deprotection of the acetal and hydrosilylation of unsaturated carbon-carbon bonds, and can also be applied to linear acetals. A possible mechanism is tentatively proposed. This journal is the Partner Organisations 2014.

Alkyl methyl ethers and alkyl methyl carbonates were synthesized by reaction of alcohols with dimethyl carbonate in the presence of tungsten and cobalt carbonyls. Optimal reactant and catalyst ratios, as well as reaction conditions, were found for selective formation of alkyl methyl ethers or alkyl methyl carbonates.

The first demonstration of a 100% atom-efficient selective reduction of less reactive ketones over aldehydes using heterogeneous catalysts is reported. Extremely high selectivities for intra- and intermolecular reductions of ketones over aldehydes were achieved. This system was also applicable to a column reactor, leading to a gram-scale synthesis.

A high yielding three-component reaction between β-iodo ethylamine derivatives, MeOH and gaseous CO2 at ambient temperatures and pressures is reported using silver(i) oxide. Unfunctionalised alkyl iodides were also found to be effective in this transformation and their optimisation is also described. To highlight the ease and control with which gaseous CO 2 can be captured and functionalised under mild conditions, the reaction was performed using 13C-enriched CO2 to afford specifically 13C-carbonyl-labelled dialkyl carbonates with exquisite control of the isotopic purity in good yields and without the need for specialised equipment.

A measure of the quantitative effect of proximate fluorine substituents on the rates of SN2 and E2 reactions has been obtained through a study mainly of reactions of fluorinated n-alkyl bromides with weak base, strong nucleophile azide ion and strong base/nucleophile methoxide ion in the protic solvent methanol and the aprotic solvent, DMSO. The order of reactivity for SN2 reactions of azide in methanol at 50 °C was found to be: n-alkyl-Br > n-alkyl-CHFBr > n-perfluoroalkyl-CH2CH 2Br n-perfluoroalkyl-CH2Br > n-alkyl-CF2Br. Approximate relative rates of reaction were: 1, 0.20, 0.12, 1 × 10 -4, -5. The order of reactivity for E2 reactions was found to be: n-perfluoroalkyl-CH2CH2Br n-alkyl-CF2Br > n-alkyl-CHFBr > n-alkyl-Br. The approximate relative rates for reaction of methoxide in methanol at 50 °C were: 1100, 4.4, 1.9, 1.

The invention provides a method for producing a vinyl ether compound, characterized in that the method includes isomerizing an allyl ether compound represented by formula (I) or (II): (wherein R1 represents a C1 to C6 alkyl group; each of R2, R3, and R4 independently represents a hydrogen atom, a C1 to C6 alkyl group, or a C3 to C6 alkenyl group; and n is 1 or 2) in the presence of hydrogen, a monodentate tris(ortho-substituted aryl) phosphite, and a rhodium compound. The vinyl ether compound is useful as a raw material, an intermediate, etc. for producing pharmaceuticals, agrochemicals, polymers, etc.

A range of methyl and ethyl ethers of aliphatic alcohols have been synthesized cleanly in high yield by reacting the corresponding alcohol with dimethyl carbonate or diethyl carbonate over the solid acid catalyst, I-alumina. The reaction could be conducted at ambient pressure without the need for the large excess of dialkyl carbonate as previously reported in the literature. If the reaction was conducted at high pressure, the conversion of the starting alcohol was greatly reduced. However, high pressure CO2 can be used as the solvent without significant reduction in yield. This has implications for tandem reactions.

The development of high-yielding, "greener" chemistry-based routes for the continuous synthesis of methyl ethers are reported in this study. Ethers have been efficiently produced using a methodology which eliminates the use of toxic alkylating agents and reduces the waste generation that is characteristic of traditional etherification processes. For the first time it is shown that the use of acidic heterogeneous catalysts can successfully achieve etherification when using scCO2 as a reaction medium. Furthermore, the relative efficiencies of three alternative methylating agents, dimethyl carbonate, dimethyl ether and MeOH, have been compared and contrasted for the methylation of 1-octanol. Dimethyl carbonate has proven to be the superior methylating agent, demonstrating higher conversion and selectivity. Successful methylation of secondary alcohols, diols, carboxylic acids and amines using dimethyl carbonate in supercritical carbon dioxide has also been shown. Substrate structure was found to influence the temperature required to maximize the yield of the desired product, substrates with multiple hydroxyl groups requiring the highest temperatures.

Method for producing 1-octene from butadiene by dimerizing and alkoxylating butadiene in the presence of one or more alkoxy substituted phosphine ligands under alkoxydimerization conditions with an alkoxydimerization catalyst, the alkoxydimerization conditions being effective to produce an alkoxydimerization product with one or more alkoxy substituted octadienes comprising primarily 1-alkoxy substituted octadiene; hydrogenating the alkoxydimerization product under hydrogenation conditions effective to produce a hydrogenation product which is primarily 1-alkoxy substituted octane; eliminating the alkoxy group from the hydrogenation product under elimination conditions effective to produce an elimination product which is primarily 1-octene and a first alkanol having from about 1 to about 3 carbon atoms; and separating the 1-octene from said elimination product.

The specific rates of solvolysis of n-octyl fluoroformate have been measured at 24.2°C in 28 pure and binary solvents. For the 23 solvents for which both NT(solvent nucleophilicity) and YCl (solvent ionizing power) values are known, a correlation using the two-term Grunwald-Winstein equation leads to sensitivities towards changes in the two scales of 1.80 ± 0.13 (l value) and 0.79 ± 0.06 (m value), respectively. For seven solvents, a parallel study was made of n-octyl chloroformate solvolysis and F:Cl specific rate ratios were, in most instances, above unity, consistent with the association step of an association-dissociation (addition-elimination) pathway being rate-determining.

Different amides have been selectively mono-N-alkylated using catalytic heterogeneous palladium and carbonyl compounds as alkylating agents. The same salt free method has been applied to the synthesis of ethers from alcohols. Reaction parameters have been studied in detail and a mechanism is proposed.

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Zirconium (benzyldiethylammoniomethylphosphonate chloride)phosphate Zr(HPO4)2-x (O2PCH2N+Et2CH2ph·Cl-)x·H2O, (0.25 x 0.75, ZBEPC-ZP) were prepared for the first time and characterized by IR and elemental analyses. ZBEPC-ZP catalyzed some typical PTC reactions in L/S/L phases were carried out to give good results. ZBEPC-ZP can be easily separated from the reaction mixture and recovered about 70-100%, and can be reused and did not show any change in activity after 10 cycles.

The investigation presented in this paper explores the mechanistic aspects and synthetic potentials of PET activation of organoselenium substrates.Fluorescence quenching of 1DCN* by a number of organoselenium compounds (RCH2SeR', 1-4), correlation of the fluorescence quenching rate constants with the oxidation potentials of 1-4, and the dependence of photodissociation quantum yields of 1-4 on their concentration suggests the occurence of electron transfer processes between 1DCN* and 1-4.Steady-state photolysis of 1-4 in the presence of 1DCN* leads to the efficient one-electron oxidative heterolytic dissociation of the carbon-selenium bond to produce the carbocation (RCH2(1+) or equivalent) and radical-centered selenium species (R'Se(.)) via the intermediacy of cation-radical .Nucleophilic assistance in the fragmentation of (RCH2SeR')(1+.) by methanol has been suggested on the basis of products obtained from the control PET reaction of neopentyl phenyl selenide (8).The synthetic utility of these findings has been demonstrated for the deselenylation (Table 4) as well as one-spot sequential selenylation-deselenylation (Table 5) reactions.

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In the presence of BF3*Et2O, organocopper and cuprate reagents promote the substitution of one alkoxy group of an acetal.Under the same conditions, alkoxy tetrahydropyrans react selectively, by ring cleavage.Chiral cyclic acetals, having a C2 axis of symmetry are diastereoselectively cleaved.The method serves to synthesize chiral secondary alcohols, after the removal of the chiral auxiliary.

A one-pot addition reaction of an alcohol to an olefinic double bond was successfully performed by use of paired electrosynthesis with a Raney-nickel cathode.

Isotopic analysis of the unsaturated products 6 and 15 resulting from irradiation of the labeled iodides 1-1,1-d2, 1-2,2-d2, and 13-1-d has revealed that they are formed substantially, but not exclusively, via α elimination.The unsaturated products thus arise via competing pathways involving carbene intermediates as well as the previously recognized radical and carbocationic intermediates.Irradiation of iodide 22 in methanol-d afforded ether 23 with partial incorporation of deuterium, but the accompanying ether 24 was formed with no detectable incorporation.Thus, ether 23 is formed via competing pathways involving the carbene 28 and the carbocation 25, whereas ether 24 is formed exclusively via the carbocationic pathway.A mechanism involving formation of the carbene intermediates via either α-hydrogen atom or α-proton transfer within the previously proposed intervening radical and ion pairs is suggested.One iodide studied, 17-2-d, exhibited no detectable α elimination.

Substitution and elimination reactions of two homologous series of compounds, induced by strong bases, were studied in aqueous alcohol and anhydrous methanol solution.Series I compounds, RF(CH2)nI having n = 2 (RF = a perfluoroalkyl group, also named an F-alkyl group), gave only RFCH=CH2 under all conditions.By contrast, RF(CH2)3Igave 4-10 times as much substitution as elimination products.Isomerization of RFCH2CH=CH2 (6) to RFCH=CHCH3 (7) occurred; this result may account, in part, for the extremely high 7/6 alkene ratios (37-81/1) obtained from elimination reactions of RFCH2CHICH3.All series II compounds, RFCH2CHI(CH2) nCH3 (n = 0-5), gave entirely elimination, and principally toward the RF group.E/Z isomer ratios varied from 2.65 to 5.These results were compared to those obtained from 1- and 2-iodooctane under the same conditions.A practical synthesis of CF3(CF2)5CH2CH2CH2I is described; the isomeric (F-alkyl)propenes 6 and 7 were also separately prepared.Rates of reactions under standard conditions for both series I and II compounds were measured.Kinetically, only second-order processes were observed, but a sharp break occurred in rate as the RF group was separated more than two carbons from the departing iodine atom, in series I compounds.Series II compounds reacted about one-tenth as fast as series I compounds.These results are discussed in the context of previous work with F-alkyl-substituted compounds.

Trialkyl phosphites, (RO)3P for R = methyl, ethyl, 2-propyl, and 2-octyl, were alkylated with Meerwein's salt (Me3O+BF4-) to yield the corresponding trialkoxymethylphosphonium tetrafluoroborate salts.These salts, which are all molten at room temperature, were reacted neat or in solvents with a series of nucleophiles.Thus, a variety of O, N, S, and halogen nucleophiles reacted by substitution at the R group C-O bond to give high yields after a trivial workup procedure.Rates of reaction were measured for substituted benzoic acids (4-XC6H4CO2H; X= CH3, t-Bu, CH3O, H, CF3, CN, NO2) with the neat salts under pseudo-first-order conditions or with the salt in CH3CN under second order conditions.The resulting Hammett plots indicate very little change in sensivity to the substituents when R = isopropyl compared with R = methyl and when the salt itself instead of CH3CN is solvent.

n-Octyl ethers are obtained by reacting n-octyl halides with performed alkoxides, or better, prepared in situ from ROH and solid KOH.Reactions are performed without any solvent but in the presence of a catalytic amount of tetra-alkyl ammonium salt (Aliquat 366).Good yields (>=92percent for primary R) are obtained at moderate temperatures and with easy work up; for t-C4H9O, elimination is a side reaction, and the effects of temperature and of the nature of the leaving group were examined, so that t-C4H9OC8H17 could then be obtained (yield 77percent) within 20 h at 36 deg C from n-octyl tosylate.

The association of BF3 to organocopper and cuprate reagents increases dramatically their reactivity towards epoxides.The same reagents cleave acetals to afford the product of substitution of one alkoxy group, whereas orthoformates lead to acetals under co

Solvolysis rate are reported for the Me, Et, n-Pr, n-Pent, n-Oct, i-Bu, neo-Pent, PhCH2CH2, and MeOCH2CH2 title compounds in MeOH, EtPH, PentOH, CH3CO2H, and CF3CO2H.Rate variations with alkyl group structure are far less than the corresponding rate variations for the tosylate solvolysis, and afford no evidence for rate-enhancing participation by β-phenyl or β-methoxy groups in the acridinium solvolyses.The n-propyl, n-pentyl, and n-octyl title compounds solvolyze in CH3OD and CH3CO2D to give mixtures of normal and rearranged products, none of which contain deuterium and which are therefore not formed via olefin intermediates.Methanolysis of the isobutyl title compounds occurs via olefin, but the acetolysis also involves an important nonolefinic pathway yielding isobutyl and sec-butyl acetates.Methanolysis products from the neopentyl derivative are heavily deuterated, but acetolysis yields undeuterated neopentyl acetate as well as deuterated tert-pentyl acetate.Product proportions calculated using GC/MS were used to deduce the fractions of reactions by various mechanistic pathways.Individual rates are calculated for solvolysis to the various unrearranged and rearranged products.They indicate that normal substitution in MeOH occurs by a classical SN2 reaction, but that such substitution in AcOH involves ion-pair intermediates.It is concluded that such ion pairs under go Me and H migration after the rate-determining stage, in competition with substitution.Activation parameters provide further evidence for the mechanistic paths proposed which are discussed in relation to literature data available for the corresponding tosylate.

Oxidation of a series of alkyl halides with alcoholic 3-chloroperoxybenzoic acid afforded the results outlined in Charts I-III and Tables I-III.The reaction was found to be a powerful and convenient method for effecting nucleophilic substitution in a variety of systems, including the highly inert 1- and 7-bicycloheptyl systems.Qualitatively, the number of molar equivalents of oxidant required varied inversely with the expected ease of substitution for a given system.A mechanism is suggested whereby the iodide is oxidized stepwise to a species RIOn in which n is an integer sufficiently large that the system in question will undergo nucleophilic substitution or elimination.Reaction in the presence of added chloride or bromide ion usually resulted in a facilitation of reaction rate and a decrease in the number of molar equivalents of oxidant required; the principal product under these conditions was usually the corresponding chloride or bromide.

A method for the synthesis of alkyl esters of α-arylalkanoic acids is given based on silver-ion-assisted (AgBF4, AgOSO2CF3, AgSbF6, AgNO3) solvolysis of alkyl acetals of primary and secondary α-halogenoalkyl aryl ketones (Hal = I, Br, Cl) in an alcoholic medium (methanol, ethanol).The reaction is quite selective and alkyl esters are the only reaction products; ethers, which are possible substitution products, are not found.The importance of masking the carbonyl as the acetal is emphasised.The reaction is found to be first-order in AgBF4 and in the primary α-halogeno acetal.A three-point Hammett correlation (ρ = -3.29) between ?+ and the rate constants suggests a large cationic contribution as well as strong aryl participation in the transition state.The role payed by the oxygen of the acetal group in the specificity of the reaction is discussed in comparison with the reactivity of analogous compounds with saturated skeletons and of α-halogenoalkyl aryl ketones.

THE EFFECTIVENESS OF ALKALI METAL FLUORIDES IMPREGNATED ON ALUMINA AS A REAGENT FOR PROMOTING ALKYLATION WAS OPTIMIZED WITH RESPECT TO THE METAL CATION, THE AMOUNT OF IMPREGNATION, AND THE REACTION SOLVENT. POTASSIUM OR CAESIUM FLUORIDE ONALUMINA IN ACETONITRILE OR 1,2-DIMETHOXYETHANE WAS CONCLUDED TO BE THE BEST REACTION SYSTEM FOR GENERAL USE. O-ALKYLATION OF SUBSTITUTED PHENOLS, PRIMARY AND SECONDARY ALCOHOLS, AND A GLYCOL WAS CARRIED OUT MOSTLY IN GOOD YIELDS UNDER MILDCONDITIONS WITH SIMPLE EXPERIMENTAL PROCEDURES.

Oxidative displacement of iodine from primary alkyl iodides and vic-substituted iodocyclohexanes with m-chloroperbenzoic acid in either dichloromethane or t-butyl alcohol-water gives primary alcohols and vic-substituted cyclohexanols, respectively.Retention of configuration at the displacement centre occurs for all of the trans-vic-substituted iodocyclohexanes except the iodoacetate and iodotrifluoroacetate where inversion of configuration occurs to give cis-hydroxy-esters.Oxidation of (S)-2-iodo-octane occurs with almost complete inversion to give (R)-octan-2-ol but also affords octan-1-ol, octan-3-ol, and octan-2-one.

Alumina coated with potassium fluoride was found to be an effective and practical reagent for the synthesis of some simple crown ethers.