REACTIONS DES DIOXAPHOSPHOLANES AVEC LES ETHYLENIQUES CARBONYLES ORIENTATION VERS LA FORMATION D'YLURES OU DE PHOSPHORANES

Abstract The reactions of cyclic phosphites and aminophosphines 1 to 4 with trans dibenzoyleethylene, methyl-fumarate, benzalacetone, 2-pentenoicacid-4-one-methylester and benzalacetophenone has been investigated. These reactions lead either to ylid formation 23, 24 and 25 or to spirophosphoranes formation 5, 6, 15 to 20. Some of these phosphoranes behave only as intermediate species and undergo a rearrangement reaction with ring expansion from 5 to 7 bonds 8, 13, 22. Attempts to rationalize these reactions and mechanisms schemes are proposed.