ASSISTANCE D'UN GROUPE VOISIN POUR DES TOSYLATES SECONDAIRES β-SUBSTITUES DIEQUATORIAUX DANS L'HEXAFLUOROISOPROPANOL 97percent

Article abstract of DOI:10.1016/S0040-4020(01)88454-4

Solvolysis rates in methanol and 97percent hexafluoroisopropanol (HFIP) for four β-methyl and β-phenyl bicyclic tosylates, show that solvent nucleophilic assistance is operating in the former solvent.However, in 97percent HFIP, for three of the mentioned compounds, the mechanism involves ? or ? neighboring group assistance.The factors influencing the occurrence of these processes are discussed.Owing to these possible neighbouring group assistances in non-nucleophilic solvents used to obtain k_c reference mechanisms, it is concluded that the k_s/k_c ratio which was proposed as a quantitative evaluation of solvent nucleophilic assistance must be used with caution.