Leaving group effects theoretical calculations

This solvation rule for 5n2 reactions can be useful in predicting the influence of a change in solvent on the structure of activated complexes. It is in agreement with studies involving leaving group heavy atom and secondary a-deuterium kinetic isotope effects, as well as theoretical calculations of solvent effects on transition-state structures. Possible limitations of this solvation rule have been discussed see [498] and relevant references cited therein. 

Clearly, from experimental observations and theoretical calculations, the relative preference of a six-membered ring for diequatorial or apjeq attachment in a TBP is low. The energies of diequatorial and apjeq cyclic TBP intermediates are similar, so that ring effects may be subordinate to other factors such as steric, stereoelectronic, apical potentiality and leaving-group ability. These latter effects are likely to determine ring orientation and conformation. 

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