2-Heptyl cation systems

Figure 9. B3LYP/6-3IG Energy profile (LE) for 6 ring (- - ) vs. 5 ring (—) dehydrocyclization in the 2-heptyl cation system. The arbitrary zero reference point is the cis 1-5-p-H-bridged cation 16 (see footnote (a) in Table II). The transition-state structures have been shown in Figure 6. The product ions are the I-2-dimethylcyclopentyl cation 20 and the I-methylcyclohexyl cation 21, respectively, and these have almost the same energy at B3LYP/6-3IG level.

Olah et al. (1966) have recently carried out a detailed U.V. investigation of 10 to 10 M solution of alkyl cations in FSOsH-SbFs solution at — 60° and were able to confirm that they have no U.V. absorption above 210 my. Solutions of t-butyl, t-pentyl and t-heptyl cations in FSOsH-SbFs are stable for hours at —60°, and N.M.R. studies have demonstrated that the ions are quantitatively formed from their corresponding alcohols in these systems (Olah et al., 1965). 

Deuterium-labelling studies revealed that no more than a few percent cyclo-propylcarbinyl-cyclopropylcarbinyl cation rearrangement takes place in the parent 2-bicyclo[4.1.0]heptyl system. However, acid-catalyzed alcohol rearrangement and... 

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