Styrenes cyclic—

In addition to propene and ethene many other alkenes (higher alkenes, styrenes, cyclic alkenes) have been polymerized with these new catalysts and a great variety of new polymers and oligomers have been synthesized, including plastic materials with melting points as high as 500°C, novel rubber materials etc. Several new polymers can now be made by catalyst design. Basically, the con-... 

Butz, S., Baethge, H., and Schmidt-Naake, G. 2000. N-Oxyl mediated free radical donor-acceptor co- and terpolymerization of styrene, cyclic maleimide monomers and n-butyl methacrylates. Macromolecular Chemistry and Physics 201 2143-2151. 

PBT (20-80)/PPE (15-50)/SEBS (5-25)/styrene-cyclic ortho ester copolymer (2-15) TSE at 270 °C/impact strength vs. blends with unfimctionalized PS/PS copolymer prepared using styrene and 4-methacryloyloxymethyl-2-methoxy-2-methyl-l,3-dioxolane, fm example Khouri 1993... 

Poly(styrene), 3-star Poly(styrene), 9.4-star Poly(styrene), (6-15.5) stars Poly(styrene), cyclic... 

Polystyrene disulfide Direct pyrolysis and flash pyrolysis MS - Styrene, cyclic styrene sulfides, diphenylthiophen - [42]... 

Metallocene catalysis can also make possible the production of copolymers of propylenes with monomers such as long-chain olefins, cyclic olefins and styrene which is not possible with more conventional Ziegler-Natta catalysts. 

Adduct 100 is formed from the 1,4 cycloaddition of o-quinone (99) with the morpholine enamine of cyclohexanone (125). Treatment of styrene oxide with cyclic enamines at elevated temperatures (about 230°C) produces O.N-ketals possessing a furan nucleus (125a). 

A more complicated behaviour was obtained with divinyl ether due to the formation of both cyclic structures and pendent vinyl groups in the chain. The failure of such olefins as styrene and isopropenylbenzene to give copolymers with 2-fural-dehyde, and in fact to homopolymerize in its presence, was blamed on the strength of the complex formed between the initiator and the aldehyde, believed too stable to initiate polymerization. 

The copper-catalyzed additions of sulfonyl chlorides to conjugated dienes and trienes73 as well as to aryl-substituted cyclic olefins74 and substituted styrenes have been described75 for example, arenesulfonyl chlorides add to vinylarenes providing good to excellent yields75 of /J-chlorosulfones ... 

Reaction 31 appears to be little affected by substituent electronic effects or by steric effects of either sulfonyl chloride or styrenes. Treatment of /5-chlorosulfones with triethylamine in benzene affords the corresponding a, /5-unsaturated sulfones in excellent yield. The copper-catalyzed addition of sulfonyl iodides to simple and cyclic alkenes has also been exploited76. 

The propagating species involved in the polymerization of cyclic formal seem to resemble carbocations, and random copolymers are formed in the copolymerization of cyclic formals with styrene. For the copolymerization of DOL with styrene, the DOL-St cross-sequence was estimated, by NMR or by chemical methods, from the decrease of the formal unit in the copolymer and the formation of nearly random copolymer was confirmed132. ... 

A more practical, atom-economic and environmentally benign aziridination protocol is the use of chloramine-T or bromamine-T as nitrene source, which leads to NaCl or NaBr as the sole reaction by-product. In 2001, Gross reported an iron corrole catalyzed aziridination of styrenes with chloramine-T [83]. With iron corrole as catalyst, the aziridination can be performed rmder air atmosphere conditions, affording aziridines in moderate product yields (48-60%). In 2004, Zhang described an aziridination with bromamine-T as nitrene source and [Fe(TTP)Cl] as catalyst [84]. This catalytic system is effective for a variety of alkenes, including aromatic, aliphatic, cyclic, and acyclic alkenes, as well as cx,p-unsaturated esters (Scheme 28). Moderate to low stereoselectivities for 1,2-disubstituted alkenes were observed indicating the involvement of radical intermediate. 

The initiation of the cyclic siloxane monomers with a living polymeric lithium species such as polystyryl lithium leads to block copolymers, as outlined in Scheme 2, were also of interest. These styrenic-siloxane block copolymers were prepared with siloxane contents from 10 to 50 weight percent. 

The stereochemistry of dienes has been found to have a pronounced effect in the concerted cyclo-additions with benzyne 64>65h A concerted disrotatory cyclo-addition of tetrafluorobenzyne, leading for example with trans- (3-methylstyrene to (63, R = Me), is likely and in accord with the conservation of orbital symmetry 68>. However while the electro-cyclic rearrangement of (63, R = H) to (65, R = H) is not allowed, base catalysed prototropic rearrangement is possible. A carbanion (64, R = H) cannot have more than a transient existence in the reaction of tetrafluorobenzyne with styrene because no deuterium incorporation in (65) was detected when either the reaction mixture was quenched with deuterium oxide or when the reaction was conducted in the presence of a ten molar excess of deuteriopentafluorobenzene. 

Murakami and coworkers [267] described a combination of an intermolecular ene-yne metathesis followed by a disrotatory 6ir-electrocyclic reaction to give six-membered cyclic dienes. Thus, reaction of 6/3-98 and of styrene (6/3-99) in the presence of a ruthenium catalyst at 100 °C led to the condensed cyclohexadienes 6/3-100, in good yield (Scheme 6/3.29). 

In an extension, we recently reported the formation of cyclic carbonates respectively from epichlorohydrin (Scheme 2.13) and styrene oxide, with carbon dioxide under catalysis by KI in the presence of a crown ether [48],... 

The primary 14C KIEs in the 1,3-dipolar addition of N-w-diphenylnitrone, PhCH=N(0)Ph, and styrene to yield 2,3,5-triphenylisoxazoline 226198 are also consistent with Huisgen s199 concerted, cyclic mechanism and inconsistent with the diradical mechanism200 (structures 227 and 228). 

The theoretical interpretation of the results was made (334) in terms of the molecular orbital perturbation theory, in particular, of the FMO theory (CNDO-2 method), using the model of the concerted formation of both new bonds through the cyclic transition state. In this study, the authors provided an explanation for the regioselectivity of the process and obtained a series of comparative reactivities of dipolarophiles (methyl acrylate > styrene), which is in agreement with the experimental data. However, in spite of similar tendencies, the experimental series of comparative reactivities of nitronates (249) toward methyl acrylate (250a) and styrene (250b) are not consistent with the calculated series (see Chart 3.17). This is attributed to the fact that calculation methods are insufficiently correct and the... 

---