Styrene epoxide, 3-buten

Styrene epoxide on reaction with 3-buten-l-ol in the presence of a catalytic amount of BiCl3 gave two possible isomers, of which the m-isomer was found to be the major one [25] (Fig. 1). The scope and versatility of the method is depicted in... 

Intramolecular oxonium ylide formation is assumed to initialize the copper-catalyzed transformation of a, (3-epoxy diazomethyl ketones 341 to olefins 342 in the presence of an alcohol 333 . The reaction may be described as an intramolecular oxygen transfer from the epoxide ring to the carbenoid carbon atom, yielding a p,y-unsaturated a-ketoaldehyde which is then acetalized. A detailed reaction mechanism has been proposed. In some cases, the oxonium-ylide pathway gives rise to additional products when the reaction is catalyzed by copper powder. If, on the other hand, diazoketones of type 341 are heated in the presence of olefins (e.g. styrene, cyclohexene, cyclopen-tene, but not isopropenyl acetate or 2,3-dimethyl-2-butene) and palladium(II) acetate, intermolecular cyclopropanation rather than oxonium ylide derived chemistry takes place 334 ). 

Several 2-thienylaodiums have likewise been treated, with epoxides to obtain the corresponding 2-( -hydroryalkyl)thiophene (Eq. 801. Among the epoxides examined in this connexion are ethylene oxide, propylene oxide, styrene oxide, 1, 2-epoxy-3-butene, and. epichloro-hydrin ... 

In nonprotic solvents, alkenes are stoichiometrically oxidized by Vv-peroxo complexes to epoxides and consecutive oxidative cleavage products in a nonstereoselective fashion. For example, cis-2-butene gave an approximately 2 1 mixture of cis- and trans-epoxides (equation 37). The reactivity of alkenes increases with their nucleophilic nature. Alkenes containing phenyl substituents such as styrene, a- and jS-methylstyrene are also very reactive and mainly give oxidative cleavage products. 

However the epoxidation of olefins lacking allylic and other reactive C-H bonds with molecular oxygen has recently been achieved on silver catalysts (Table 1). In 1997 the Eastman Chemical Company started the manufacture of 3,4-epoxy-1-butene, the product of mono-epoxidation of butadiene, on a semiworks production scale (entry 1). Remarkably enough the presence of benzylic hydrogen, as in / -methyl styrene (entry 5), drives the oxidation towards combustion, while sterically hindered allylic C-H s, as in norbornene (entry 6), are inert to oxidation. 

When an unsymmetrical secondary alcohol is formed, depending on which carbon-oxygen bond is cleaved. With propylene oxide, for example, a base-catalyzed reaction favors the formation of the secondary alcohol almost exclusively, whereas, a non-catalytic or acid-catalyzed alcoholysis yields a mixture of the isomeric ethers. However, the reactions of other a-epoxides, such as 3,4-epoxy-l-butene, 3,4-epoxy-l-chloropropane (epichlorohydrin), 3,4-epoxy-l-propanol (glycidol), and styrene oxide, are more complicated with respect to which isomer is favored. ... 

In this study we show that it is possible to selectively epoxidize higher olefins to their corresponding epoxides if the olefins do not contain reactive allylic hydrogen atoms. Many olefins, including styrene, substituted butadienes, and norbornene have been selectively epoxidized. Because of the usefulness of 3,4-epoxy-1-butene as a new chemical intermediate, most of the data and discussion will involve the selective epoxidation of butadiene. The catalyst composition and overall kinetics of the reaction will be discussed in some detail. 

Trlfluoromethanesulfonlc acid as an example of a Bronsted acid was a very active catalyst with styrene oxide, but was a poor catalyst for the butene oxide and cyclohexane oxide at room temperature. Tetrasulfone was the most active catalyst for epoxides studied. 

Table II. Sunmary of catalyst performance in the presence of various epoxides. CHO-cyclohexene oxide BO-butene oxide SO-styrene oxide.

The most noteworthy feature of the sulfenylation and selenenylation rates (represented by the triangles) is their much diminished sensitivity to substitution. This reflects both smaller electron demand in the TS and increased sensitivity to steric factors. The relatively low rate of styrene toward selenenylation is somewhat of an anomaly, and may reflect both ground state stabilization and steric factors in the TS. The epoxidation data (CH3CO3H, hexagons) show a trend similar to bromination, but with a reduced slope. There is no evidence of a rate-retarding steric component. One indicator of a strong steric component is decreased reactivity of the E-isomer in an E,Z—disubstituted alkene pair, but the rates for the 2-butene isomers toward epoxidation are very similar (Table 5.9). 

Substrates GSTM1 -1—Trans-stilbene oxide, DCNB-high, CDNB-mod-erate, Aflatoxin Bl-exo 8,9-epoxide, androstene 3,17-dione, B(a)P-diol epoxide, B(fl)P-4,5-oxide, chrysene diol epoxide, cumene hydroperoxide, ethacrynic acid, -nitrophenyl acetate, PGA2, PGJ2, styrene 7,8-oxide, fran5-4-phenyl-3-buten-2-one. 

Mn(TPP)Cl Ascorbate Cyclohexenol Styrene Styrene oxide Cyclohexene, Epoxide CIS and trans stilbenes, Epoxides CIS- and trans-2-hexenes, Epoxides 2,3-Dimethyl-2-butene, Epoxides [83]... 

Figure 1 Polymer interpretation chart. PAI, polyamideimide PC, polycarbonate UP, unsaturated polyester PDAP, diarylate phtalate resin VC-VAc, vinyl chloride-vinyl acetate copolymer PVAc, polyvinyl acetate PVFM, polyvinyl formal PUR, polyurethane PA, polyamide PMA, methacrylate ester polymer EVA, ethylene-vinyl acetate copolymer PF, phenol resin EP, epoxide resin PS, polystyrene ABS, acrylonitrile-butadiene-styrene copolymer PPO, polyphenylene oxide P-SULFONE, poly-sulfone PA, polyamide UF, urea resin CN, nitrocellulose PVA, polyvinyl acetate MC, methyl cellulose MF, melamine resin PAN, polyacrylonitrile PVC, polyvinyl chloride PVF, polyvinyl fluoride CR, polychloroprene CHR, polyepichlorohydrin SI, polymethylsiloxane POM, polyoxy-methylene PTFE, polytetrafluoroethylene MOD-PP, modified PP EPT, ethylene-propylene terpolymer EPR, ethylene-propylene rubber PI, polyisoprene BR, butyl rubber PMP, poly(4-methyl pentene-1) PE, poly(ethylene) PB, poly(butene-l). (Adapted from Ref. 22, p. 50.)...

Vinyl-functional alkylene carbonates can also be prepared from the corresponding epoxides in a manner similar to the commercial manufacture of ethylene and PCs via CO2 insertion. The most notable examples of this technology are the syntheses of 4-vinyl-1,3-dioxolan-2-one (vinyl ethylene carbonate, VEC) (5, Scheme 24) from 3,4-epoxy-1-butene or 4-phenyl-5-vinyl-l,3-dioxolan-2-one (6, Scheme 24) from analogous aromatic derivative l-phenyl-2-vinyl oxirane. Although the homopolymerization of both vinyl monomers produced polymers in relatively low yield, copolymerizations effectively provided cyclic carbonate-containing copolymers. It was found that VEC can be copolymerized with readily available vinyl monomers, such as styrene, alkyl acrylates and methacrylates, and vinyl esters.With the exception of styrene, the authors found that VEC will undergo free-radical solution or emulsion copolymerization to produce polymeric species with a pendant five-membered alkylene carbonate functionality that can be further cross-linked by reaction with amines. Polymerizations of 4-phenyl-5-vinyl-l,3-dioxolan-2-one also provided cyclic carbonate-containing copolymers. 

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