Vinyl mesitylene

Ivin and Spensley (10) tested the Lowry Case II model and equations for the anionic copolymerization of vinyl mesitylene (Mi) with a-methyl-styrene at 0°C. by varying the total concentration of the two monomers while keeping their mole ratio constant. As pointed out above, theory predicts a dependence on absolute monomer concentration when depropagation occurs. Table I summarizes some of Ivin and Spensley s data. 

CH2==CHC6Ha(013)5, vinyl mesitylene CHa CHCgH Cl, o-chiorostyrene p-chlorostyrene... 

A purely thermal homopolymerization to high molar masses has only been proved for styrene and some of its derivatives, as well as for 2-vinyl pyridine, 2-vinyl furan, 2-vinyl thiophene, methyl methacrylate, and acenaphthylene. In contrast, vinyl mesitylene, 9-vinyl anthracene, and methyl acrylate do not polymerize spontaneously. Some of fhe thermal polymerizations proceed by a free radical mechanism others, however, do not. 

Abbreviations aapy, 2-acetamidopyridine Aik, alkyl AN, acetoniuile Ar, aryl Bu, butyl cod, 1,5-cyclooctadiene COE, cyclooctene COT, cyclooctatetraene Cp, cyclopentadienyl Cp , penta-methylcyclopentadienyl Cy, cyclohexyl DME, 1,2-dimethoxyethane DME, dimethylformamide DMSO, dimethyl sulfoxide dmpe, dimethylphosphinoethane dppe, diphenylphosphinoethane dppm, diphenylphosphinomethane dppp, diphenylphosphinopropane Et, ethyl Ec, feirocenyl ind, inda-zolyl Me, methyl Mes, mesitylene nb, norbomene orbicyclo[2.2.1]heptene nbd, 2,5-norbomadiene OTf, uiflate Ph, phenyl PPN, bis(triphenylphosphoranylidene)ammonium Pi , propyl py, pyridine pz, pyrazolate pz, substituted pyi azolate pz , 3,5-dimethylpyrazolate quin, quinolin-8-olate solv, solvent tfb, teti afluorobenzobaiTelene THE, tetrahydrofuran THT, tetrahydrothiophene tmeda, teti amethylethylenediamine Tol, tolyl Tp, HB(C3H3N2)3 Tp , HB(3,5-Me2C3HN2)3 Tp, substituted hydrotiis(pyrazol-l-yl)borate Ts, tosyl tz, 1,2,4-triazolate Vin, vinyl. 

On the other hand, the involvement of vinyl cationic species in the reaction cannot be ruled out in some cases, as shown in Scheme 4. In this context, it was found that the reaction of 3-butyn-2-one with mesitylene can occur without Pd(OAc)2, clearly indicating the involvement of vinyl cations generated from alkynes and H+ in this reaction.47 1 The yield difference in the presence and in the absence of Pd(OAc)2 may be explained by the competition between [Pd(n)02CF3]+ and vinyl cationic species in the electrophilic substitution of aromatic G-H bonds. Recent kinetic isotope experiments suggest a mechanism involving alkyne coordination to Pd(n) followed by electrophilic aromatic substitution.476... 

The mechanism of the Au(III) catalysis proposed in Scheme 5 implies the stereoselective formation of the new C-C bond which, of course, cannot be observed in the final product when terminal alkynes are used (the aryl group and the former alkyne hydrogen are situated at the same side of the double bond in the vinyl-Au intermediate). For the reaction of 1-phenyl-l-propyne and mesitylene 1 (see below, Table 1) the proposed mechanism should lead to preferential formation of the Z isomer which is, in fact, observed [2]. The formation of a small amount of E isomers can be explained by isomerization of the initially formed Z compound. Such isomerization was, in fact, observed directly in the case of related electron-poor alkynes [4],... 

Thermolysis of terminal vinyl azides has generally led to the isolation of products other than azirines. A number of j8-azido-styrene derivatives have, on pyrolysis, yielded indoles. Thus /S-azido-a-methylstyrene, (60) when boiled in mesitylene, produced an 80% yield of 3-methylindole (61) and 9% of a-phenylpropionitrile (62) Decomposition of the same compound in ethanol, however, gave only a trace of the indole the major product, isolated in about... 

CO. CHa, CO2, acetone, ketene. ethene. propene, 1-butene, benzene, toluene, mesitylene. xylene, methyl ethyl ketone, diethyl ketone, methyl-n-propyt ketone, methyl-n-butyl ketone, ethyl vinyl ketone, methyl propenyl ketone (trace), ethyl propyl ketone (trace), 3-methyl-cydopenlanone, cyclohexanone (trace), cyclohexa-2-enone, 2-methyl-cyclohexanone, 1-methyl-cydohexa-1-ene-3-one (trace), acrolein, mesityl oxide, ethanal, propanal. butanal. chain fragments, some monomer... 

Our search for a more active system led us to bis(pentafluorophenyl)nickel complexes originally reported by Klabunde and co-workers in the 1980s [56]. One of the more interesting complexes reported was (// -toluene)Ni(C6F5)2 (Fig. 4.26). Toluene can be readily replaced by a number of neutral electron donors including xylene, mesitylene, THF, PEtj, and norbornadiene. In fact, Klabunde noted that formation of (norbornadiene)Ni(C6F5)2 was accompanied by intractable polymer. Klabunde speculated that vinyl addition polymerization occurred with possible crosslinking. Unfortunately, the insolubility of the norbornadiene polymer prevented further analysis. 

Bi- and tricyclic fused heterocycles, including allyl vinyl ether moieties, undergo thermal rearrangement in refluxing toluene, xylenes or mesitylene (Eq. 3.1.38)... 

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