Reactions of trico-ordinate phosphorus compounds with phosphorus pseudohalogens. Part 2. Pentaco-ordinate intermediates in the reaction of o-phenylene neopentyl phosphite with diethoxyoxophosphoranesulfenyl chloride

Abstract

Reaction between oxophosphoranesulfenyl chloride 1(R = R′= EtO) and o-phenylene neopentyl phosphite 4 takes predominantly the deoxygenation course, yielding the phosphorochloridothioate 7 and the phosphate 8. Formation of minor products 5 and 6 corresponding to the desulfurization pathway, and low-temperature ³¹P NMR observations, are rationalized by proposing phosphoranephosphonium equilibria which are shifted towards phosphorane structures 9, 13, 11. These results supplement our earlier studies on desulfurization and deoxygenation of compound 1 with tricoordinate phosphorus compounds and add new evidence for phosphonium–phosphorane equilibria.