Acetolysis of the toluene-p-sulphonate ester of 2-(2-hydroxyethyl) -6,6-dimethylbicyclo[3.1.13 hept-2-ene (nopol) (1; R = OH) gave a good yield of the acetate of the previously unknown tricyclic pinane derivative 8,8-dimethyltricyclo[5.1.1 .02*5] nonan-2P-01 (4a). This molecule has a bridgehead hydroxy group, and so is remarkably stable to acids, despite being highly strained from having two cyclobutane rings. However, the hydroxy group is adjacent to the new cyclobutane ring, so that (4a) is readily oxidised to the gcetate of the hydroxytetrahydrofuran, 2phydroxy-8,8-dimethyl-l O-oxatricyclo-15.1.1 -1 29s]decane (5; R = OAc). Hydrolysis of the acetate group, followed by oxidation of the alcohol (5; R = OH), yields 8,8-dimethylbicyclo[5.1.1] nonane-2,5-dione (6). The base-catalysed dehydration of 2-(2-hydroxyethyl)-6,6dimethylbicyclo[3.1.l]hept-2-ene (nopol) (1; R = OH) yields a mixture of the dienes (2) and (3), but the reaction does not yield any tricyclic pinane derivatives., The Clarke-Eschweiler cyclisation has been demonstrated3 to take place with 2-(2-aminoethyl)-6,6-dimethylbicyclo[3.l.l]hept-2-ene (nopyl- amine) (1; R = NH,), but does not yield a system with a pinane skeleton; rearrangement gives products based on the fenchyl and terpinyl systems. The only reported tricyclic pinane derivative is 1 O,lO-dimethyltricyclo~7.1. 1.02*7]undec-2( 7)-en-6-one, prepared from P-pinene during the synthesis of P-~elinene.~ In this case, a second six-membered ring was added to the pinane skeleton. This suggested that a pinane with two cyclobutane rings may well exist, but could be highly labile, and thus isolable only under mild conditions. We attempted to prepare it by the solvolysis of the toluene-p-sulphonate of nopol. Results and DiscussionThe toluene-p-sulphonate of nopol (1; R = OH) was prepared by conventional methods. It readily underwent solvolysis in

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terpenes terpenes U 0200 -1553α-Acetoxy-6,6-dimethylbicyclo [3.1.1]heptane-2-spiro-1'cyclopropane from Nopylamine Deamination.-Deamination of nopylamine hydrochloride (I) with nitrites in AcOH proceeds via initial formation of a diazonium ion yielding spirocyclopropane (V) as the main product and (II), (III), and (IV) as side products, depending on the reaction conditions. These results are in contrast to the acetolysis of nopyl tosylate, where 8,8-dimethyltricyclo[4.2.1.0 3,7 ] nonan-6-ol is obtained as the main product. The difference is suggested to result from the transition state being reacted early (deamination) or late (tosylate acetolysis) on the reaction coordinate. -(ABRAHAM, R. J.; JONES-PARRY, R.; GIDDINGS, R. M.; GUY, J.; WHITTAKER, D.; J.

Apopinen (I) reagiert mit Pd(II)‐chlorid und Eisessig je nach den Bedingungen zu den Spaltprodukten (II) bzw. zu Trimethylbenzol (III).