5- Methyl-2-norbornene

A vinylcyclopropylidene to cyclopentenylidene isomerization evidently also taken place when 7,7-dibromo-bicyclo[4.1.0]hept-2-ene and 8,8-dibromo-bicyclo[5.1.0]-oct-2-ene are treated with methyllithium. The former compound is converted to 7-bromo-7-methyl-norbornene by intermolecular insertion into the C -Br bond of methyl bromide, whereas tetrahydropentalene is obtained from the latter [113]. 

Figure 3.5 Variation of retention (net retention volume per unit surface area of stationary phase) with the temperature in GSC. Stationary phase GTCB (carbon). Solutes o/p-xylene (1), m-xylene (2), n-octane (3), ethylbenzene (4), toluene (5), n-heptane (6), methylcyclohexane (7), exo-5-methyl-norbornene (8), endo-5-methylnorbornene (9), norbornane (10) and norbomene (11). Figure taken from ref. [309], Reprinted with permission. 

Grubbs has investigated the stereochemistry of ROMP using titanocene—metallacyclobutane complexes. These complexes offer little control over olefin stereochemistry or tacticity in the polymerization of norbornene. ° However polymerization of rac-1-methylnorbornene yielded a polymer with 90—95% trans-olefins and a partially regioregular (head—tail) sequence of monomers (the tacticity of the polymer was not determined). Using a related CpzTi—metallacyclobutane complex, a polymer of anti-7-methyl-norbornene was formed that was 80% trans in configuration and was partially syndiotactic ([r] =... 

The rates and equilibrium constants for isomerization of various [2,2,1] and [2,2,2] alkenes are reported. For example methylenenorbornane is more stable than 2-methyl-norbornene, but in the [2,2,2] series the endocyclic alkene is the more stable. The Pb(OAc)4 decarboxylation of a variety of [3,2,1] and [2,2,2] bicyclic carboxylic acids seems to proceed by two competing routes. ... 

Hasselman has investigated the thermal rearrangements at 190°C of the methylated methylenebicyclo[3,2,0]heptenes (498)—(501). Rate constants for the decomposition of each of the possible isomeric bicyclo[3,2,0]heptenes and bicyclo-[2,2,l]heptenes (502)—(505) have been calculated. The activation energies are ti-mated to lie in the range 38—41 kcal mol and are consistent with the formation of biradical intermediates (506) or (507). The results are not consistent with the intermediacy of freely rotating biradicals. In particular, the ratio of the rates of formation of the methylated norbornenes (502) and (503) from the bicyclo[3,2,0]heptenes (500) and (501) were found to be 1.33 and 1.43 respectively. If freely rotating biradicals were involved, the ratio of (502) and (503) formed from the isomeric bicyclo[3,2,0]heptenes (498) and (499) should lie between these values, irrespective of the stereochemistry of the methallyl portion of the biradical formed. In fact the ratios observed from (498) and (499) are not the same as those from (500) and (501). The intermediates therefore appear to be non-equilibrating biradicals, in which product formation competes with rotation about the central bond. 

Methyl Norbornene Dicarboxylic Anhydride (Memtetrahydro-phthalic Anhydride) 8 NR >240 ... 

Brown, H. C., and K.-T. Liu Additions to Bicyclic Olefins. VII. Electrophilic Addition of Hydrogen Chloride and Deuterium Chloride to Norbornene, 2-Methyl-norbornene, and Related Bicyclic Olefins. Evidence for a Carbonium Ion Process and the Capture of Unsymmetrical (Classical) 2-Norbornyl Cations. J. Amer. Chem. Soc. 97, 600 (1975). 

In a 200-ml three-necked flask fitted with a dropping funnel (drying tube) is placed a solution of 13.4 g (0.12 mole) of 1-octene in 35 ml of THF. The flask is flushed with nitrogen and 3.7 ml of a 0.5 M solution of diborane (0.012 mole of hydride) in THF is added to carry out the hydroboration. (See Chapter 4, Section I regarding preparation of diborane in THF.) After 1 hour, 1.8 ml (0.1 mole) of water is added, followed by 4.4 g (0.06 mole) of methyl vinyl ketone, and the mixture is stirred for 1 hour at room temperature. The solvent is removed, and the residue is dissolved in ether, dried, and distilled. 2-Dodecanone has bp 119710 mm, 24571 atm. (The product contains 15 % of 5-methyl-2-undecane.) The reaction sequence can be applied successfully to a variety of olefins including cyclopentene, cyclohexene, and norbornene. 

Wolfe and Wagener have developed main-chain boronate polymers (59) (Fig. 38) by the acyclic diene metathesis (ADMET) polymerization of symmetrical ,oj-dienes, containing both methyl- and phenyl-substituted boronate functionalities using Mo and Ru catalysts.84 The ring-opening metathesis polymerization (ROMP) of several norbornene monomers containing methyl- and phenyl-substituted boronates into... 

Well-defined nanoclusters (w 10-100 A diameter) of several metals have been prepared via the polymerization of metal-containing monomers. The synthetic approach involves the block copolymerization of a metallated norbornene with a hydrocarbon co-monomer which is used to form an inert matrix. Subsequent decomposition of the confined metal complex affords small clusters of metal atoms. For example, palladium and platinum nanoclusters may be generated from the block copolymerization of methyl tetracyclododecane (223) with monomers (224) and (225) respectively. 10,611 Clusters of PbS have also been prepared by treating the block copolymer of (223) and (226) with H2S.612 A similar approach was adopted to synthesize embedded clusters of Zn and ZnS 613,614... 

Bui (10 equiv.), methyl acrylate (2 equiv.) norbornene (6 equiv.), CS2CO3, CH3CN, 80 C, 1 d... 

The report by Basset and co-workers on the metathesis of sulphur-containing alkenes using a tungsten alkylidene complex, mentioned previously for the acyclic cross-metathesis reaction (see Sect. 2.2), also contained early examples of ring-opening cross-metathesis of functionalised alkenes [20]. Allyl methyl sulphide was reacted with norbornene in the presence of the tungsten catalyst 5, to yield the desired ring-opened diene 35 (Eq. 29). 

Unfortunately, this product was isolated as a mixture with diene 36, formed from cross-metathesis with a second equivalent of the allyl sulphide, and was contaminated with some polymeric residues. It is also important to note that an excess of the sulphide was required to suppress competing ROMP of the norbornene. A similar result was obtained for the reaction of allyl methyl sulphide with cyclop entene. 

Nonadienoic acid, 4-methyl-, trans, ethyl ester, 53, 116 Nonan-5-ol, 52, 22 D-NORANDROST-5-EN-36-0L-16-CARBOXYLIC ACIDS, 52, 53 Norbornene, with ethyl tri-... 

It has been reported by R.Scheiner that phenylazide forms triazoline compounds by 1,3-cyclic addition to unsaturated olefines such as n-butylethylene and norbornen(9 ). These triazolines are decomposed photochemically or thermally to give imine compounds and aziridine as is shown in scheme 1. These facts suggest that phenylazide may react with 3-methyl-1-butene to give triazoline in a similar reaction to that with norbomen. 

Steele, W.V., Chirico, R.D., Cowell, A.B., Knipmeyer, S.E., and Nguyen, A. Thermodynamic properties and ideal-gas enthalpies of formation for 2-aminoisobutyric acid (2-methylalanine), acetic acid, ( -5-ethylidene-2-norbornene, mesityl oxide (4-methyl-3-penten-2-one), 4-methylpent-l-ene, 2,2 -bis(phenylthio)propane, and glycidyl phenyl ether (1,2-epoxy-3-phenox3q>ropane), / Chem. Eng. Data, 42(6) 1053-1066, 1997. 

As discussed in previous paragraphs, a disadvantage of TS-1 catalyst is its limited pore size, which restricts the number of oxidants that can be employed ° °. By using larger pore molecular sieves this restriction could be overcome. Titanium-substituted MCM-41 ° and titanium-grafted MCM-41 were shown to be particularly active in the epoxidation of bulky olefins like pinene and norbornene with TBHP. In the case of Ti-MCM-41 silicas, the importance of hydrophobicity in the system was demonstrated by the faster reaction rate observed with 2-methyl-l-phenyl-2-propyl hydroperoxide as the oxygen atom... 

An autoclave was charged with 2-acetyl-5-norbornene (64 g), 5 wt% palladium on carbon (3.4 g), and 200 ml of methyl alcohol and then filled with a hydrogen atmosphere. The mixture was stirred at ambient temperature for 14 hours and then filtered through Celite , concentrated, and 53.3 g of product isolated. 

Analogous methyl azidoformate forms with norbornene a thermal unstable triazoline.251 The decomposition products are 40% aziridine and 55% imide. Furthermore it has been observed that the rate of nitrogen evolution of the triazoline from methyl azidoformate increases threefold when triglyme and 20-fold when dimethyl sulfoxide are substituted for 1,1-diphenylethane as solvents. This fact supports a betaine intermediate in the thermal decomposition reaction. The triazoline from 2,4-dinitrophenyl azide and norbornene could just be isolated, but from picryl azide only the aziridine was obtained.252-254 Nevertheless, the high negative value of the activation entropy (—33.4 eu) indicates a similar cyclic transition state for both reactions. 

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