Chloro-1,7,7-trimethylbicyclo heptane

Scheme 7.46. The formation of camphene hydrochloride (ex< -2-chloro-233-trimethylbicyclo[2.2.1]heptane and its rearrangement to isobomyl chloride (ex<7-2-chloro-l,7,7-trimethylbicyclo[2.2.1]heptane).The addition of a proton to the carbon-carbon double bond of camphene 3,3-dimethyl-2-methyienebicyclo[2.2.1]heptane is shown as accompanied by o-bond migration to produce a singie ion with partial bonding to two sites (called, variously, nonclassical or bridged ) or a pair of rapidly equilibrating ions. The classical ions are shown, leading to the observed products. Debate raged over a period of years about the nature of the ion or ions lying between the starting materials and products. Additional discussion is provided in Chapter 8.

Scheme 7.47. A pathway using classical ions and the Wagner-Meerwein rearrangement as well as nonclassical ions to depict the formation of pinene hydrochloride (exo-2-chloro-2,6,6-trimethylbicyclo[3.3.1]heptane) from a-pinene (2,6,6-trimethylbicyclo[3.1.1]-2-heptene) and 3-pinene (2-methylene-6,6-dimethylbicyclo[3.3.1]heptane) and the subsequent interconversion of pinene hydrochloride (eA o-2-chloro-2,6,6-trimethylbicyclo[3.3.1]heptane) and bornyl chloride (enrio-2-chloro-l,7,7-trimethylbicyclo[2.2.1]heptane).

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