Cyclohexene oxide/tetrahydrofuran

It is interesting that the reaction in the oxirane-carbon dioxide tetrahydro-furan system with (dmca)AlCl produced the respective terpolymer, especially when cyclohexene oxide was used as the oxirane. The cyclohexene oxide tetrahydrofuran-carbon dioxide terpolymer appeared to contain up to 29mol.-% carbon dioxide and 20mol.-% tetrahydrofuran units [244]. 

A detailed study of mechanisms both of photodecomposition of triarylsul-fonium salts to yield Bronsted acids and of catalysis of cationic polymerization of representative monomers—styrene oxide, cyclohexene oxide, tetrahydrofuran (THF), and 2-chloroethyl vinyl ether—was reported in 1979 by Crivello and Lam [14]. Crivello [15] and Green et al. [16] provided further reviews shortly thereafter. The mechanisms of photodecomposition of a variety of initiators for free radical photopolymerization, including onium salts, were compared by Vesley [17] in 1986. A review, similar in scope, but providing more mechanistic detail was also published in 1986 by Timpe [10a]. An updated coverage of aspects of this chemistry has been provided by the same author in his review of photoinduced electron transfer polymerization [10b]. 

The monomers of styrene oxide, 1,4-cyclohexene oxide, trioxane, and vinyl ether were polymerized at satisfactory rates. However, tetrahydrofuran, e-caprolactone, and cc-methylstyrene could not be polymerized7). 

Support for direct initiation by PS+ was recently obtained by experiments on the polymerization of cyclohexene oxide using anthracene labelled polytet-rahydofuran as the sensitizer. In this case poly(tetrahydrofuran-b-cyclo-hexeneoxide) is formed [66]. 

Examples of intramolecular trapping of carbonyl ylide dipoles by alkenes have now been reported.These include, for example, the conversion of the oxirane (172) into the tetrahydrofuran (173). Carbonyl ylides have also been prepared by irradiation of 2,3-bis-(p-methoxyphenyl)oxirane in the presence of dicyanoanthracene as electron-transfer sensitizer direct or triplet-sensitized irradiation, however, leads mainly to rearrangement via carbon-oxygen bond cleavage. In contrast, cyclohexene oxide and styrene oxide, on naphthalene-sensitized irradiation in alcohols, undergo solvolysis via oxide anion-radical intermediates. ... 

Carbocations generated in this way can add directly to appropriate monomers (e.g., tetrahydrofuran, cyclohexene oxide, n-butyl vinyl ether) or can form Bronsted acids by abstracting hydrogen from surrounding molecules. This method, which is commonly referred to as free-radical-promoted cationic polymerization, is quite versatile, because the user may rely on a large variety of radical sources. Some of them are compiled in Table 10.9. 

Strong Bronsted acids form when diaryliodonium salts containing anions, like B 4, AsF6, PF6, and SbFe , are reduced with compounds like ascorbic acid in the presence of cop r salts. Such acids also initiate polymerizations of tetrahydrofuran, cyclohexene oxide, and 5-trioxane. ... 

A soln. of triphenylphosphine and CF3SO3H in dichloromethane treated with a soln. of cyclohexene oxide in the same solvent at room temp., and refluxed for 8 h - product. Y 65%. F.e., incl. ring opening of oxetane and tetrahydrofuran, also with trifluoroacetic acid, and regioselectivity s. S. Yamamoto et al., Bull. Chem. Soc. Japan 61, 4476-8 (1988). 

In addition to ethylene and propylene oxide, a variety of other cyclic ethers have also been copolymerized with MA. Monomers such as cyclohexene oxide,piperylene dimer mono and diepoxide, epichlorohydrin, " " 3,3,3-trichloropropylene oxide, " tetrahydrofuran, " " and ethylene carbonate or ethylene sulfite " have received attention. Condensation reactions between allyl glycidyl ether and MA are reported to be highly useful for preparing plastics with remarkable hardness, high heat distortion, and brilliant clarity.The cyclohexene oxide copolymerizations were second order in MA, with an activation energy of 13.8 kcal/mol. For the epichlorohydrin system the rate was dependent on the temperature and proportional to the catalyst concentration, with an activation energy of 14.5 kcal/mol. 

Hydrophobic blocks are more often poly(propylene oxide) or poly( 1,2-butylene oxide) however, epichlorohydrin, tetrahydrofurans, styrene oxide, cyclohexene oxide, and allyl glycidyl ether can be used. The hydrophilic blocks are generally poly(ethylene oxide), although glycidol and butadiene monoxide can be used. 

B. 2-(4-Methoxyphenyl)-2-cyclohexen-1-one. A 500-mL, round-bottomed flask, equipped with a 1.5-in. Teflon-coated magnetic stirring bar and an argon inlet adaptor, is charged with 10.02 g (45.1 mmol) of 2-iodo-2-cyclohexen-1-one, 10.69 g (70.4 mmol, 1.56 eq) of 4-methoxyphenylboronic acid (Note 8), 16.72 g (72.1 mmol, 1.6 eq) of silver(l) oxide (Ag20) (Note 9), 0.85 g (2.8 mmol, 6 mol %) of triphenylarsine (Note 10), 0.53 g (1.4 mmol, 3 mol %) of palladium(ll) bis(benzonitrile)dichloride (Note 11), 200 mL of tetrahydrofuran (THF) and 25 mL of water (Note 12). The reaction mixture, flushed with argon, is stirred for 1 hr and then quenched by the addition of 125 mL of saturated aqueous ammonium chloride. After the solution is stirred for 1 hr, the... 

The active oxidant was proposed to be a Ru(V)=0 species and access of benzene towards the Ru=0 bond is facilitated by the flat structure of the salicyldiimine ligand (see Fig. 8). This catalytic system was also applied to the epoxidation of stilbene, C-H bond activation of cyclohexane or cyclohexene and the oxidation of tetrahydrofuran to y-butyrolactone [37]. We conclude however, that a suitable and catalytic system for the selective oxidation of benzene to phenol has not yet been forthcoming. 

Ionization potential of Continued) butenone, 123 cyclic diacetylenes, 305 cyclohexene, 48, 102 cis-cyclooctene, 102 Zraus -cyclooctene, 102 DABCO, 81 dimethyl ether, 123 ethylene, 80, 319 formaldehyde, 123, 319 hydrogen atom, 55, 75 methanol, 123 methyl acetate, 123 methyl acrylate, 123 nitrous oxide (N2O), 172 norbornadiene, 48 norbornene, 48 oxetane, 123 tetrahydrofuran, 123 trimethylamine, 81 water, 123... 

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