The Abnormal Hydrolysis of 7-Phosphanorbornenium Salts: A Case of Phosphonium-Phosphenium Equivalence

摘要

Phosphonium salt hydrolysis is certainly one of the most fundamental and well-studied reactions in organophosphorus chemistry.The accepted mechanism is schematized in eq 1.rnWhen Wittig discovered pentaarylphosphoranes, he also showed that when phosphorus is incorporated in a five-membered ring, one of the favored decomposition pathways involves a reductive elimination, as shown in eq 2.On this basis, it seemed quite possible to alter the normal course of a phosphonium salt hydrolysis to get a phosphinous acid instead of the classical phosphine oxide (eq 3).