Structural Effects in Solvolytic Reactions. 51. Examination of the Differences in the Behavior of Secondary and Tertiary U-Shaped Bicyclic Derivatives toward Solvolysis

Article abstract of DOI:10.1021/jo00350a028

The solvolyses (acetolysis) of secondary bicyclic tosylates such as cis-bicyclo<3.3.0>oct-2-yl and 5,6-endo-trimethylene-8-norbornyl and -9-norbornyl proceed with low exo/endo rate ratios (<10), unlike secondary 2-norbornyl (280) and the analogous tertiary derivatives wherein the exo/endo rate ratios increase progressively with increasing U-shaped character.The possible factors responsible for this difference in behavior are discussed.One possible factor can be nucleophilic solvent participation in the secondary systems, absent both in secondary 2-norbornyl and in tertiary solvolyses.An examination of the products of acetolysis of a number of bicyclic secondary tosylates reveals predominant inversion during acetolysis, suggesting solvent participation.