Norbornyl systems rearrangement

The rearrangements of the 2-norbornyl cation are unexceptional. All 1,2-alkyl shifts, even those in acyclic systems (Section 7.6.1) conform to essentially the same pattern. Individual differences exist in the rates of alkyl shift, relative to the rates of capture by solvent. In that respect the 2-norbornyl cation is superior to acyclic analogs because it can approach the geometry of corner-protonated nortricyclene with only small distortions of the nuclear positions. (A more sophisticated treatment in terms of relaxation theory has been published548. ) Other bicyclic and polycyclic systems provide similarly favorable conditions for 1,2-alkyl shifts. Some of them will be discussed in the following Sections. 

The exo endo rate ratio can be correctly predicted without due regard for anchimeric assistance this points to its absence. Hence the initial product to ionize these systems is the classical tertiary 2-norbornyl cation. This conclusion, however, does not preclude the possibility of the subsequent rearrangement of the classical cation into a nonclassical one, nor does it give any evident of the relative stability of classical and nonclassical tertiary 2-horbomyl cations. 

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