Camphene, addition

After addition of a few milliliters at 15°C, the thick slurry thins slowly and the remainder of the sulfuric-glacial acetic acid mixture was added at 0° to 2°C. A total of about 2 hours was required for the addition. After addition, stirring was continued for 15 minutes. Then dropwise, over an hour, a solution of 178 g (1.3 mols) of dl-camphene in 50 ml of glacial acetic acid was added while keeping the temperature at about 0°C ( 3°C). 

The LIS (Lanthanide Induced Shift) NMR technique is useful for such analysis25 and the separation of olefin enantiomers such as limonene, a-camphene and /J-pinene has been performed upon addition of silver salts such as Ag(fod) or Ag(hfc) to the commonly used lanthanide chiral salts such as Ln(tfc )3 or Ln(hfc)3, where fod = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyloctanedione, hfc = heptafluoro-3-butyrylcam-phorato and tfc = trifluoroacetylcamphorato. 

While aqueous HF is unreactive towards alkene addition, anhydrous HF is surprisingly reactive. The addition of HF to simple alkenes, such as ethylene, propene and cyclohexene, has been effected by mixing the reagents in an appropriate metal container at temperatures of -78 to -45 °C, and gradually heating the mixture from room temperature to 90 C.7-9 Representative yields are 60-80%. Catalysts are unnecessary. Markovnikov addition is observed, but the stereochemistry of addition to norbomene is not clear.10 With bomylene11 and camphene,12 HF addition gives excellent yields of a mixture of products. 

The addition of ligands in the hydroformylation of camphene influenced the reaction to endo product, while without ligands, an equal ratio between the exo and the endo product was observed. The selectivity for the two linear isomers was 100%. 

Another method for catalyst separation is the previously mentioned liquid/liquid technique which was studied by Gusevskaya with limonene, camphene, and myrcene in a toluene/biphasic system with Rh/TPPTS as the catalyst [47]. The addition of cationic cetyltrimethylammonium chloride (CTAC) was crucial to overcome the mass transport problems of this two-phase system. All three terpenes gave high conversions, between 71% and 96%, while the admixing of CTAC was positive in the case of myrcene and limone and negative for the reaction with camphene. 

With the tandem catalyst Pd/Sn, the hydroesterification of limonene delivered a 90% yield of the linear product, while in the absence of tin, more branched esters were formed. The hydroesterification of camphene delivers the linear product with a selectivity of 90%, whereas the two diastereomers were built in an equal ratio. The additive SnCl2 had a high impact on catalytic activity without this additive, the palladium/diphosphinobutane catalyst had lower activity. 

Turpentine. Turpentine is used directly as a solvent, thinner, or additive for paints, varnishes, enamels, waxes, polishes, disinfectants, soaps, pharmaceuticals, wood stains, sealing wax, inks, and crayons, and as a general solvent. The chemistry of its mono-terpenes offers many possibilities for conversion to other substances, as illustrated in Fig. 28.20. There is increasing use of turpentine to produce fine chemicals for flavors and fragrances. An important use of turpentine is in conversion by mineral acids to synthetic pine oil. It also is a raw material for making terpin hydrate, resins, camphene, insecticides, and other useful commodities. These uses are included in the following summary of its applications. 

The conversion of ( )-camphor into the substituted camphene (168) by BF3,Et20-catalysed addition of ethyl diazoacetate should prove useful in sesquiterpenoid synthesis the isomeric camphene (169) is also obtained, but is converted quantitatively into (168) on treatment with zinc-acetic acid.262 The luminescence spectra of... 

Manganese(m) acetate oxidation (cf. Vol. 3, p. 34) of camphene gives (186) as a 95 5 mixture by carboxymethyl radical insertion no rearranged products were obtained, in contrast to /3-pinene which gave Wagner-Meerwein products only, and no free-radical insertion.279 The E- and Z-isomers of (187) probably result from a non-concerted biradical intermediate formed by benzyne addition to camphene.280 Benzyl-lithium adds to the aminocamphor (188) exclusively from the exo-side whereas only the competing enolization reaction occurs with more sterically hindered organometallics.281... 

Ranganathan also reports iodine azide addition to camphene in MeCN at —10 °C to give two compounds 288 the minor component is (5 X = CHI) and the major component is probably (199 X = N3, Y = CH2I) and not the proposed unstable (199 X = I, Y = CH2N3). 2-Bornene yields (201) and the endo-azide (202) as major products, together with a small amount of the isomeric exo-azide.287... 

The addition of methanol to alpha-pinene in the presence of the above mentioned beta zeolite as catalyst in the batch reactor results in the cleavage of the cyclobutane ring and yields l-methyl-4-[alpha-methoxy-isopropyl]-l-cyclohexene (alpha-terpinyl methyl ether) as the main reaction product. The most common by-products to be found are isomerization compounds like camphene, limonene and terpinolene, and several bicyclic and double addition products, e.g. endo- or exo-methylbomylether, endo- or exo-methylfenchylether and cis- or trans-1,8-dimethoxy-p-menthane. 

The addition of hydrogen fluoride across double bonds in unsaturated bicyclic terpenes is accompanied in many cases by rearrangements. Hence, hydrofluorination of camphene with... 

Higher-chlorinated camphenes are the most plausible side products. They may be formed together with other cyclic carbon skeletons if the Wagner-Meerwein rearrangement (to polychlorinated bornanes) is hindered [38, 39]. The ionic addition of chlorine to the primary olefinic carbon is always in competition with radical chlorination. Although the first mechanism is more likely, the second one may also take place. It was found that a gentle chlorination of... 

The formation of polychlorinated dihydro camphenes is not as straightforward as it might seem. Addition of HCl to the double bond of camphene [44] is unlikely since an ionic attack at the double bond is more favorable due to the... 

Additional chemical diversity of monoterpenes is apparent from the natural occurrence of their bicyclic analogs that bear cyclopropane (carane and thujane types), cyclobutane (pinane type), and cyclopentane (camphene/bornane, isoeamphane and fenchone types) rings (Figs. 6 and 7). The carane type of bicyclic monoterpenoids in plants is represented by (+)-3-carene... 

In addition to ( )-valerane, a wide variety of other sesquiterpenes, including ( )-ishwarane, ( )-ish-warone, ° copaene, ylangene, ( )-seychellene ( )-sativene, ( )-longifoline, " ( )-copa-camphene," ( )-damsin," ( )-A < >-capnellene, ( )-pentalenene, (-)-P-vetivone" and ( )-P-eudesmol have been synthesized by pathways involving cycloalkylation of saturated ketone enolates. 

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