Assistance d'un groupe voisin pour des tosylates secondaires β substitues diequatoriaux dans l'hexafluoroisopropanol 97%
作者:J. Laureillard、E. Casadevall
DOI:10.1016/s0040-4020(01)88454-4
日期:1984.1
Solvolysis rates in methanol and 97% hexafluoroisopropanol (HFIP) for four β-methyl and β-phenyl bicyclic tosylates, show that solvent nucleophilic assistance is operating in the former solvent. However, in 97% HFIP, for three of the mentioned compounds, the mechanism involves π or σ neighboring group assistance. The factors influencing the occurrence of these processes are discussed. Owing to these
β-甲基和β-苯基四环甲苯磺酸盐在甲醇和97%六氟异丙醇(HFIP)中的溶剂分解速率表明,溶剂亲核助剂正在前一种溶剂中运行。但是,在97%的HFIP中,对于上述三个化合物,该机理涉及π或σ邻基团辅助。讨论了影响这些过程发生的因素。由于在用于获得k c参考机理的非亲核溶剂中存在这些可能的邻近基团辅助作用,因此得出结论,必须谨慎使用提议作为溶剂亲核助剂的定量评估方法的k a / k c比值。