Bis (trimethylsilyl)[(4-fluorophenyl)(trimethylsiloxy) methyl] phosphonate (Ia). To a solution of 10.7 g of tris (trimethylsilyl) phosphite in 30 ml of methylene chloride, a solution of 3.7 g of 4- fluorobenzaldehyde in 10 ml of methylene chloride was added dropwise with stirring at 10oC. The reaction mixture was stirred for 0.5 h and heated to boil. The solvent was removed, and the residue was distilled in a vacuum to give 10.5 g of phosphonate Ia, yield ...