Addition Reaction Of Alcohols Research Articles

Radical addition reaction of alcohols to 1-(4-nitrophenyl)-5H-pyrrolin-2-one

Quantum chemical calculations of the parameters of the 1-(4-nitrophenyl)-5H-pyrrolin-2-one molecule have been carried out by the MNDO method. The radical addition reaction of aliphatic, alicyclic, and aromatic alcohols to 1-(4-nitrophenyl)-5H-pyrrolin-2-one with the formation of 3- and 4-substituted pyrrolidones has been investigated.

The Mechanism of Addition of Phenols to Tetramesityldisilene. Evidence for Both Nucleophilic and Electrophilic Rate-Determining Steps

Following the synthesis of the first stable disilene, tetramesityldisilene (1), in 1981,1 many reactions of disilenes have been chronicled.2 However, information about the mechanisms of these reactions is still rather scarce. One of the most studied mechanisms is that of the 1,2-addition reaction of alcohols to the SidSi bond, but also this mechanism is not fully understood.2 Addition of alcohols to (E)-1,2-di-tert-butyl-1,2-dimesityldisilene gives a 1:1 mixture of the two diastereoisomeric alkoxysilanes, suggesting a stepwise mechanism involving a zwitterionic intermediate.3 In contrast, theoretical calculations (at the RHF/6-31G* level) predicted a four-center concerted transition state, leading to syn-addition, for the gas-phase addition of water to disilene.4 In agreement, Sekiguchi, Maruki, and Sakurai (SMS) found recently that the addition of 2-propanol and of tert-butyl alcohol to the transient disilenes (E)and (Z)-1,2-dimethyl-1,2-diphenyldisilene occurs with high syndiastereoselectivity.5 With ethanol the addition occurs with high syn-diastereoselectivity at low ethanol concentrations, but at a high ethanol concentration a 1:1 mixture of the addition diastereoisomers was obtained. No significant kinetic deuterium isotope effect was found when ethanol-d1 was used. SMS concluded that the rate-determining step of the addition reaction involves a nucleophilic attack of the alcoholic oxygen on the coordinatively unsaturated silicon center, forming a fourmembered intermediate which reacts further, either intramolecularly to give syn-addition products or intermolecularly (at high alcohol concentrations) to give anti-addition products.5 This contrasts with the common addition mechanism to olefins, which generally involves a rate-determining electrophilic step. To gain further insight into the mechanism of alcohol addition reactions to disilenes, we have carried out the first Hammetttype6 study for compounds with multiple bonds to silicon. We studied the kinetics of the addition reactions of seven paraand meta-substituted phenols to 1. The resulting Hammett plot has a concave shape with a minimum for phenol, indicating a change in mechanism from a rate-determining nucleophilic step for electron-rich phenols, to a rate-determining electrophilic step for electron-poor phenols. Kinetic isotope effect measurements support this interpretation. The kinetics of the addition of phenols to 1 was followed spectroscopically by measuring the decay rate of the absorption at 420 nm (corresponding to the SidSi bond in 11).7 A large access of the phenol (i.e., 50-6000-fold larger than that used for 1) was used to enforce pseudo-first-order kinetics. Plots of the pseudo-first-order rate constants (kobs) vs phenol concentrations are shown in Figure 1.8 The excellent correlations between the experimental measurements and first-order kinetics and the linear correlations in Figure 1 imply that the addition reactions are indeed first order in both the disilene and the phenol.9 The second-order rate constants k for the addition of the various phenols to 1 derived from Figure 1 are summarized in Table 1.10 Comparison with the results of SMS shows that the rate of addition of phenols to 1 (k ≈10-4-10-2 M-1 s-1) are much slower compared with the rates of addition of alkyl alcohols to (E)and (Z)-1,2-dimethyl-1,2-diphenyldisilene and 1,2,2-trimethyl-1-phenyldisilene (k ≈ 107-108 M-1 s-1).5 The larger steric bulk of the mesityl substituents in 1 may account for this large reactivity difference. A Hammett plot of log(kX/kH) vs σ (eq 1),6 where kX and kH are the second-order rate constants for the addition to 1 of the substituted and the nonsubstituted phenols, respectively (Table 1), is shown in Figure 2.

ChemInform Abstract: Investigation of Particularity of Catalytical Addition Reaction of Alcohols and Diols to Bicyclo(2.2.1)heptenes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Organosilicon Compounds. Part 302. Regio‐ and Stereochemistry and Kinetics in the Addition Reactions of Alcohols to Phenyl‐Substituted Disilenes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The chemistry of organosilicon compounds. 302. Regio- and stereochemistry and kinetics in the addition reactions of alcohols to phenyl-substituted disilenes

A phenyl-substituted disilene, PhMeSi=SiMe 2 , and stereoisomeric disilenes (E)- and (Z)-PhMeSi=SiMePh were generated photochemically from newly designed precursors. These phenyl-substituted disilenes were detected spectroscopically in an argon matrix at 10 K. Introduction of the phenyl group(s) caused a large red sift in the Si=Si absorption. The reactions of these disilenes with alcohols such as i-PrOH, t-BuOH, and EtOH were examined. PhMeSi=SiMe 2 gave the addition products PhMeHSi-SiMe 2 OR, regioselectively. (E)- and (Z)-PhMeSi=SiMePh gave the corresponding alkoxyhydrodisilanes in high diastereoselectivity arising from syn addition of alcohols to the intermediate disilenes. A mechanism involving a four-membered intermediate is proposed for the addition reaction of alcohols to disilenes

Synthesis of (E)- and (Z)-2,3-Bis(trifluoromethyl)allyl Alcohols by γ-Ray Irradiation of Hexafluoro-2-butyne with Alcohols and Some Reactions

Abstract Radiation-induced addition reaction of alcohols to hexafluoro-2-butyne provided (E)- and (Z)-2,3-bis(trifluoromethyl)allyl alcohols, which were dehydrated to afford 1,2-bis(trifluoromethyl)-1,3-butadienes. Thermal cyclization of 3-methyl-1,2-bis(trifluoromethyl)-1,3-butadiene afforded 1-methyl-2,3-bis(trifluoromethyl)clobutene.

ChemInform Abstract: Addition Reaction of Alcohols to Diethyl 2,2‐Difluoro‐1‐(trifluoromethyl)ethenyl Phosphate (I) in the Presence of Alcoholates (II).

ChemInform Abstract: Addition Reaction of Alcohols to Diethyl 2,2‐Difluoro‐1‐(trifluoromethyl)ethenyl Phosphate (I) in the Presence of Alcoholates (II).

ChemInform Abstract: A New Synthesis of 2‐Amino‐γ‐lactones Involving Photochemical Addition Reaction of Alcohols to Enamide.

AbstractMethyl pyruvate (I) is converted into the enamide (IV) which does not undergo cyclization when irradiated in the presence of sodium borohydride.

A New Synthesis of 2-Amino-g-lactones Involving Photochemical Addition Reaction of Alcohols to Enamide

Photoaddition de methanol, ethanol, cyclohexane et tetrahydrofuranne sur la N-benzoyl N-benzyl deshydroalanine

Hydrophobic Vitamin B12. IV. Addition Reactions of Alcohols to Olefins as Catalyzed by Hydrophobic Vitamin B12 Derivatives

Abstract Addition reactions of alcohols to olefins were catalyzed by hydrophobic vitamin B12 derivatives under aerobic irradiation conditions at the room temperature range. Ethyl vinyl ether, 1-pentene, and cyclohexene were adopted as olefins, while heptamethyl methylaquacobyrinate perchlorate and heptamethyl cyanoaquacobyrinate perchlorate were used as the starting complexes. Heptamethyl cobyrinate, which was generated from heptamethyl methylaquacobyrinate perchlorate by aerobic photolysis, is an appropriate catalyst for investigation of the reaction mechanism because the alkylated complex having the cobalt–carbon σ-bond, the reaction intermediate, has a long lifetime sufficient for its identification in the dark. On the other hand, heptamethyl cyanocobyrinate, which was derived from heptamethyl cyanoaquacobyrinate, is superior to heptamethyl cobyrinate as the catalyst for the addition reaction. The reaction proceeds via light-promoted decomposition of the alkylated complex, and the catalyst is regenerated upon autoxidation by air. These hydrophobic vitamin B12 derivatives are particularly effective homogeneous catalysts for the addition of an alcohol to an electron-rich olefin. Plausible reaction schemes for the catalytic cycle have been presented on the basis of experimental findings.

ChemInform Abstract: THE REGIOSELECTIVE ADDITION OF ALCOHOLS TO ISOPRENE WITH RHODIUM TRICHLORIDE HYDRATES

Rhodium trichloride hydrates gave predominantly the 1,2-addition product, 2-alkoxy-2-methylbut-3-ene, in the addition reaction of alcohols to isoprene. The regioselective path was established by assuming the formation of the π-(2-methylbut-3-en-2-yl)rhodium complex.

The Regioselective Addition of Alcohols to Isoprene with Rhodium Trichloride Hydrates

Abstract Rhodium trichloride hydrates gave predominantly the 1,2-addition product, 2-alkoxy-2-methylbut-3-ene, in the addition reaction of alcohols to isoprene. The regioselective path was established by assuming the formation of the π-(2-methylbut-3-en-2-yl)rhodium complex.

Activity of a new polyoxime‐copper complex in the reversible uptake of molecular oxygen and carbon monoxide, in the polymerization of acrylonitrile, and in the addition reaction of alcohols to acrolein

AbstractA new polyoxime‐copper complex was prepared from cupric acetate and a polyoxime which is considered to consist largely of 1,2‐bis(hydroxyimino)trimethylene units. The properties of the complex were studied. Its ESR spectrum was found to be similar to that of the low molecular weight copper(II) complex, whose intensity decreases with increasing copper content. The complex shows a catalytic activity in the Michael type addition reaction of alcohols to acrolein, yielding exclusively β‐alkoxypropionaldehyde. In addition, it initiates the polymerization of acrylonitrile under hydrogen pressure (40 to 90 kg/cm2). Furthermore, the complex with a composition ratio Cu: OX ≈ 1:4 (Cu: number of copper atoms, OX: number of hydroxyimino groups in the complex), after being treated with hydrazine hydrate in methanol under nitrogen, can reversibly take up and release ca. 3,2dm3 of molecular oxygen (in water) and 0,8dm3 of carbon monoxide (in methanol) per mole of copper. These activities decrease remarkably with decreasing copper content of the complex.

Preparation and reactivity of cyanoalkyl complexes of platinum(II)

Neutral and cationic cyanoalkyls of platinum(II) have been prepared; in some cases the coordination of the CN group promotes cis trans isomerization, as well as addition reaction of alcohols to give imino ether complexes, while the longer chain cyanoalkyls undergo CO insertion.

The γ-Radiation-induced Radical Addition Reaction of Alcohols

The -radiation-induced radical addition reactions of such alcohols as CH30H, C2H50H, n- C3H70H and i-C3H70H to such polyflorocyclobutenes as(CF2)2CH=CCI(1), (CF2)2CF=CCI (2)and(CF2)2CH=CF(3)were studied.In the case of (1)and(2), the attack of the -hydroxyalkyl radicals to the cyclobutenes occurred exclusively on the=CH or CF of the unsymmetrical double bond, yielding the corresponding 1:1 adducts. While, in the case of(3), the radicals attacked on either the =CHor =CF, yielding the two isomers, (CF2)2CH2CFCRR/OH(7)and(CF2)2CHFCHCRR' OH(8).The ratio of the two isomers varied markedly with the structure of the alcohols, and this was attributed to the steric effect of alkyl groups of the alcohols.

Initiation of free-radical addition reactions of alcohols by tertiary butyl hydroperoxide

1. Tert-Butyl hydroperoxide can be used as an initiator of the chain radical reaction for the addition of alcohols to the methyl esters of acrylic and maleic acids. 2. The decomposition of tert-butyl hydroperoxide in butanol and cyclohexanol at 115° obeys the first-order reaction. 3. tert-Butyl hydroperoxide in butanol at 115° undergoes mainly induced decomposition, with a small proportion of the decomposition going through the stage of forming the complex with the alcohol.

The Radiation-Induced Addition Reaction of Alcohols to 1,2-Dichlorotetrafluorocyclobutene and 1,2-Dichlorohexafluorocyclopentene

The Radiation-Induced Addition Reaction of Alcohols to 1,2-Dichlorotetrafluorocyclobutene and 1,2-Dichlorohexafluorocyclopentene

Substituent effects on the addition of alcohols and anilines to organic isothiocyanates

The addition reactions of alcohols, ROH (R = CH 3, C 2H 5 n-C 3H 7, i-C 3H 7 and t-C 4H 9), to p-bromophenylisothiocyanate show that the rates decrease in the order, CH 3OH > C 2H 5OH > n-C 3H 7OH > i-C 3H 7OH > t-C 4H 9OH, although the basicities of the alcohols vary in the reverse order. The results indicate the greater importance of steric factors as compared with polar factors. Evidence is also presented for the formation of a complex between the isothiocyanate and the alcohol in the first stage of the addition reaction. In the addition of aniline to substituted phenylisothiocyanates the rate data give a satisfactory linear correlation with Hammett σ constants and the results clearly show that electron-withdrawing groups favour the addition reaction. The addition of aniline to alkyl isothiocyanates have been studied in order to find out the nature of alkyl group interaction in these derivatives. Kinetic studies on the addition of substituted anilines to phenylisothiocyanate show that the rate of reaction increases with the electron-donating ability of the substituents on the aniline as also the basicity of the aniline.

The Radiation-Induced Addition Reaction of Alcohols to Perhalogeno Olefins

A study was made of the gamma radioinduced addition reaction of alcohols to perhalogeno olefins, such as 1,2,2-trichloro1 -fluoroethylene, 1,2- dichloro -1,2-difluoroethylene, and 1,1-dichloro-2,2--difluoroethylene. The general reaction is: CHR1R2OH + CFX = CX2 yields CHX2 CFXCR1R2OH, whe re X = F or Cl; R1 = H or CH3; R2 = H, CH3, or C2H5 . In preliminary experiments, benzoyl peroxide was found to be effective for the addition reaction, but benzoates of alcohols were produced as byproducts whose boiling products were similar to the 1: 1 adducts. The gamma radioinduced addition reaction of 1,2,2-trichloro-1- fluoroethylene and 1,2-dichloro1,2-difluoroethylene gave mainly 1: 1 adducts in appreciahle yields. 1,1-Dichloro-2,2-difluoroethylene reacted with alcohols under the influence of gamma radiation to form telomers. The yields and physical properties of the 1: 1 adducts, the new halogeno alcohols, are tabulated. The trend in gross reactivity observed in the addition of alcohols to 1,2- dichloro-1,2-difluoroethylene is as follows: (CH3)2CHOH> CH3(CH2)2OH, CH3CH2OH> C H3OH. Chemical reactions were used to determine the direction of the additions of alpha -hydroxyalkyl radicaly formed to 1,2,2-trichloro1-fluoroethylene and 1,1-dichloro-2,2- difluoroethylene. The results confirm the general rule for the addition of radicals to the olefins, that is, that the radicals add to the sidemore » having less steric hindrance.« less

Guanyl-o-Alkylisourea. II

An addition reaction of alcohol on dicyandiamide in the presence of copper salt catalyst has been investigated. Guanyl-o-alkylisourea copper complex salt was synthesized with quantitative yield. By removing the copper from this complex copper salt, its salt was prepared with good yield. A high yield of guanyl-o-alkylisourea salt, which could not have been obtained when the acid catalyst was used, was investigated. Some guanyl-o-alkylisourea salts were newly prepared. By using of any desired copper salt and alcohol in the copper catalyst method, it is possible to obtain corresponding guanyl-o-alkylisourea salteasily. Therefore this method is considered to be a very convenient method for general synthesis of guanyl-o-alkylisourea salt, The mechanism of the formation of guanyl-o-alkylisourea copper complex salt was proposed by assuming of the formation of dicyandiamide coppr complex salt as the inital intermediate of this reaction.