Bornyl pyrolysis

Bornene has been prepared from the reaction of 2-bromo-bornane-3-carboxyIic acid with aqueous sodium bicarbonate,6 by pyrolysis of isoborneol methyl xanthate,7 and by the j8-elimination of hydrogen chloride from bornyl chloride with sodium alkoxides in various solvents.2... 

The same products, but in different ratios, occur in the gas phase eliminations of HCl from bornyl and isobornyl chlorides and from the pyrolysis reaction of bornyl and isobornyl benzoates and methyl xanthates . The isobornyl reaction is appreciably faster than that of the bornyl ester ((iso-B/B) = 6.8 at 345 °C), but proceeds at a slightly slower rate than that of cyclohexyl acetate, (CH/iso-B) = 2.1 at 600 °K. By analogy with the nonclassical carbonium ion interpretation of the solvolysis rates of bornyl and isobornyl chlorides, the participation of nonclassical carbonium ion intimate ion-pairs, e.g. 

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