Synthesis and characterization of Six-membered spirobicyclic organophosphoranes and metallophosphoranes

Abstract

Phosphoraiaylation of O-aminobenzamide and O-mercaptobenzoic acid with pentachlorophosphorane at elevated temperature results in the isolation of some novel six-membered spirobicyclic phosphoranes 1 and _2. These hypervalent moieties, besides containing both sulphur and nitrogen being bonded to pentacoordinate phosphorus, have an open centre of reactivity in the form of a cleavable P-CI bond. This centre of reactivity has been used to synthesize potential anticancer spirobicyclic organophosphoranes containing a peptide linkage. A symbiosis of transition metal and hypervalent chemistry has also been achieved by carrying out nucleophilic substitution reactions of ! and _2 with some transition metal carbonylates. The resulting transition metal substituted spirobicycliephosphoranes are highly reactive and undergo carbonyl substitution reactions at the transition metal centre. All the species have been characterized by 1H, 31 p N MR as well as by other physico-chemical methods.