Is the Nonclassical Ion an Intermediate

The solvolyse of 2,3-tetrafluorobenzobicyclo[2,2,2]octadienes and -octenes are generally accompanied by skeletal rearrangements resulting from a 1,2-shift of the CT-bond in an anti-position to the departing group, e.g.  

In discussing these data the question arose whether the nonclassical ion 374 is an intermediate or a transition state leading to ion 318. 

In order to simplify the choice between alternative mechanisms Slinko et al. studied the solvolysis of epimeric pairs on the one hand, the configuration of the detaching group should have a decisive effect on the composition of the reaction mixture, and, on the other, with a nonclassical ion the process of trapping it by a nucleophile should not be accompanied by skeleton rearrangement. With this aim the solvolysis of 8-substituted 3,4-tetrafluorobenzobicyclo[3,2,l]octadienes and -octenes was studied. The 8-syn-e Hmers are solvolyzed with the retention of the skele- 

The suggested hypothetical schemes are fairly well corroborated by the data of Nisnevich et al. who from the epimeric sulphonates 406 and 407 generated the isomeric ions 409 and 410 the quenching of these ions by a nucleophile yielded product mixtures similar to those described for their solvolysis 

to continue earlier works e selected an epimeric pair of secondary 

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