Norbomene 5,5-dimethyl

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. 

The photocycloaddition of dimethyl maleate to norbomene yields cyclobutanes (91) and (92), while the photocycloaddition of maleic anhydride to this olefin yields (92) and (93) (after hydrolysis)<100> ... 

After elimination of ethoxytrimethylsilane, 7,7-dimethyl-1-norbomene (6) rearranges to 3,3-dimethyl-2-norbomylidene (7), which undergoes a 1,3-CH insertion reaction into the endo-6-H to give tricyclane 8. Nortricyclane formation has been shown to be the fastest intramolecular mode of stabilization of 2-norbomylidene.5,6... 

Further important industrial applications of olefin metathesis include the synthesis of 3,3-dimethyl-l-butene ( neohexene , intermediate for the production of musk perfume) from ethene and 2,4,4-trimethyl-2-pentene, the manufacture of a,co-dienes from ethene and cycloalkenes (reversed RCM), and the ROMP of cyclooctene and norbomene to Vestenamer and Norsorex , respectively. 

As is true for most reagents, there is a preference for approach of the borane from the less hindered side of the molecule. Because diborane itself is a relatively small molecule, the stereoselectivity is not high for unhindered molecules. Table 4.6 gives some data comparing the direction of approach for three cyclic alkenes. The products in all cases result from syn addition, but the mixtures result both from the low regioselectivity and from addition to both faces of the double bond. Even the quite hindered 7,7-dimethyl-norbomene shows only modest preference for endo addition with diborane. The selectivity is enhanced with the bulkier reagent 9-BBN. 

The meso-ionic l,3-dithiol-4-ones (134) participate - in 1,3-dipolar cycloaddition reactions giving adducts of the general type 136. They show a remarkable degree of reactivity toward simple alkenes including tetramethylethylene, cyclopentene, norbomene, and norbor-nadiene as well as toward the more reactive 1,3-dipolarophilic olefins dimethyl maleate, dimethyl fumarate, methyl cinnamate, diben-zoylethylene, A -phenylmaleimide, and acenaphthylene. Alkynes such as dimethyl acetylenedicarboxylate also add to meso-ionic 1,3-dithiol-4-ones (134), but the intermediate cycloadducts are not isolable they eliminate carbonyl sulfide and yield thiophenes (137) directly. - ... 

Another example of competition between the photocycloaddition reaction and energy transfer is provided by the irradiation of carbonyl compounds in the presence of dimethyl-AL(2-cyanopropyl)ketenimine 71.96 Here, the energy transfer is indicated by decomposition of the ketenimine. The ratio of photocycloaddition to decomposition products is dependent upon the n,n triplet energy of the carbonyl compound. These experiments are summarized in Table IX. Unlike the previously mentioned case with norbomene, the threshold energy for the competition is very broad, although in about the same region. 

Since peroxy acids have a relatively low steric requirement, steric hindrance mainly arises in the epoxidation of bridged cycloalkenes.224 Marked difference in exolendo selectivity was observed in the reaction of norbomene and 7,7-dimethyl-norbomene with m-CPBA236 [Eqs. (9.60) and (9.61)] ... 

In a manner analogous to classic nitrile unmes, the additions of tnfluoro-methylacetomtnle phenylimine occur regiospecifically with activated terminal alkenes but less selectively with alkynes [39], The nitrile inline reacts with both dimethyl fumarate and dimethyl maleate in moderate yields to give exclusively the trans product, presumably via epimenzation of the labile H at position 4 [40] (equation 42) The nitrile imine exhibits exo selectivities in its reactions with norbomene and norbornadiene, which are similar to those seen for the nitrile oxide [37], and even greater reactivity with enolates than that of the nitrile oxide [38, 41]. Reactions of trifluoroacetomtrile phenyl imine with isocyanates, isothiocyanates, and carbodiimides are also reported [42]... 

Hydroformylation of norbomene proceeds slowly in spite of the expected reactivity of the strained double bond. Racemization of the product aldehyde does not occur under the reaction conditions. The hydroformylation of methyl methacrylate gives only one isomer, which is a useful chiral synthon. Dimethyl itaconate also can be hydroformylated using (12) as the chiral ligand to give aldehyde product in 82% ee accompanied by hydrogenated ester.64... 

Santane dr 2,3-DimethylO norbomane 95. Santene dr 2,3-Dimethyl- 2-norbomene... 

Olefinic dipolarophiles, such as dimethyl fumarate, fumaronitrile, ethyl vinyl ether, AT-phenylmaleimide, norbomene, and norbomadiene, react with... 

Catalytic codimerizations between cyclopropenes and alkenes (or alkynes) to give four-membered rings have only been achieved with 3,3-dimethyl- and 3-cyclopropyl-3-methylcyclopropene on the one hand and norbomene or norbomadiene on the other (stereochemistry not determined)77> ... 

The transition state of the assisted ionization of 2-norbomen-7-yl p-nitrobenz-oate (395a) has been explored by comparison with the 2-methyl and 2,3-dimethyl derivatives, (402) and (403), respectively326. If participation stemmed from one end of the double bond, then the rate effect of 2,3-dimethyl substitution should double that of a 2-methyl group (statistical effect). The cumulative effect which was actually observed is evidence for the symmetrical nature of the transition state. Caution must be exercized, however, in extrapolating the symmetrical effects in the transition state to postulate a symmetrical carbocation. 

Fig. 10.23 The chemistry of PMR-15. The first stage is imidisation of the reactants, nadic anhydride monomethyl ester (NE), methylene dianiline (MDA) and 3,3 ,4,4 -benzophenonetetracarboxylic acid dimethyl ester (BTDE). The second stage is cross-linking of the norbomene end-caps.

Sulfonation was carried out by heating the asphalt with sulfur trioxide-trimethyl amine complex or sulfur trioxide-pyridine complex at temperatures near 135°C. Sulfamic acid treatment was also included in this series. Many other reagents were evaluated such as methyl methacrylate, 2-acrylamido-2-methylpropanesulfonic acid, 2-dimethyl-aminoethyl methacrylate, 2-vinylpyridine, 4-vinylpyridine, tetrahydro-phthalic anhydride, norbomene dicarboxylic anhydride, and phthalic anhydride. 

Methyl- cyclopentene 3-Methyl- cyclohexene 7,7-Dimethyl norbomene ... 

The synthesis of a,co-difunctional telomers by cross-metathesis between cyclic olefins and acyclic functionalized olefins is possible in the presence of functional-group-tolerant catalysts. Thus, cross-metathesis of dimethyl hex-3-enedioate with cycloocta-1,5-diene (Pinazzi 1980 Reyx 1982b, 1990), cyclopentene (Reyx 1986, 1987), or norbomene (Cramail 1991a) in the presence of the catalyst system WCV Mc4Sn allows the synthesis of a,m-difunctional oligomers, e.g. reaction (2). 

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