New Reactions of Alkylidenephosphoranes and their Preparative Uses. Part I: The Acid‐Base Character of Phosphonium Salts and Alkylidenephosphoranes

Phosphonium salts may be regarded as Bronsted acids, and alkylidenephosphoranes as the conjugate bases. Compounds of the two classes exist in equilibrium with each other. Phosphonium salts and alkylidenephosphoranes can be obtained by this “transylidation”. Other methods are also given for the preparation of members of both classes.