Synthesis of thiaphosphetane, thiadiphosphetane and thiazadiphosphetidine derivatives from the reaction of phosphacumulenes, phosphallene and phosphinimine with Lawesson's reagent

ABSTRACT

The active phosphacumulene ylides namely, N-phenylimino-[2], 2-oxo- [4] or 2-thioxo-vinylidenetriphenylphosphorane [6] are nucleophilic reagents which can be considered as versatile synthons for the synthesis of new heterocycles. They react with Lawesson's reagent [1] to give the corresponding thiaphosphetane derivatives 3, 5 and 7 respectively, which constitute an important class of heterocyclic compounds with medicinal and biological importance. On the other hand, Lawesson's reagent [1] can be converted by reaction with the active heteroallylic phosphonium ylide, hexaphenylcarbodiphosphorane [8], into the thiadiphosphetane 9. When the phosphinimine 10 reacts with Lawesson's reagent [1], the thiazadiphosphetidine 11 was obtained