in dichloromethane inert atmosphere, condensation of ClPF2 to soln. (-20°C) of phosphito compound at -196°C, warming to room temp. (1 h), stirring (3h), organic byproduct: 2-chloro-2,3-dihydro-1,3-dimethyl-1,3,2λ( 3)-benzodiazaphosphorin-4(1H)-one; removement of volatiles (25°C, 0.05 Torr);