Fragmentation and Insertion Reactions With 2,3-Oxaphosphabicyclo[2.2.2]oct-5-ene Derivatives; Synthesis of a 1,3,2,6-Oxathiadiphosphorinane

Abstract

Derivatives of the 2,3-oxaphosphabicyclo[2.2.2]oct-5-ene ring system with P in the thiophosphonate state, as in A, have been synthesized. The bridging P-O fragement can be eliminated on either thermal (110°) or photochemical (254 nm) treatment, and appears as the P=O group of the previously unknown and highly reactive species . In an attempt to replace O by S in B with the thionating reagent (4-MeOC₆H₄PS₂)₂, a product C was obtained which was proved by X-ray analysis to have resulted from cleavage of the O-C bond and insertion of the fragment 4-MeOC₆H₄PS₂ into the molecule. This is the first known example of the 1,3,2,6-oxathiadiphosphorinane ring system.