New and efficient approach to the synthesis of pentacoordinate spirobicyclic phosphoranes

Abstract

Pentacoordinate spirobicyclic 2-phenoxy-1,3-phenylenedioxo-1,3,2-imino(alkyl)acetoxyphosphoranes are synthesized through a new and efficient method whereby phosphorus pentachloride is displaced stepwise by catechol, an N,O-bis(trimethylsilyl)amino acid and phenol (pathway A) or catechol, phenol and an N,O-bis(trimethylsilyl)amino acid (pathway B); this method has advantages of high yields, rapid reaction times and easy operation, which might provide a new route for the synthesis of other pentacoordinate phosphoranes.