The carbonyl compound (42449-03-6, 0.40 mmol), p-toluenesulfonylhydrazine (TsNHNH2, 0.42 mmol, 1.05 eq.) and 1,2-dimethoxyethane (DME, 1.0 mL) were added sequentially to a flame-dried Schlenk flask under argon protection. The reaction mixture was heated and stirred at 60 °C for 30 min. After the solution was cooled to room temperature, diethyl phosphite (H-phosphonate 1b, 0.40 mmol, 1.0 eq.), cesium carbonate (Cs2CO3, 0.60 mmol, 1.5 eq.) and cuprous iodide (CuI, 0.04 mmol, 10 mol%) were sequentially added. The mixture was heated to 85 °C with continuous stirring. The progress of the reaction was monitored by thin layer chromatography (TLC), and when the reaction was complete, the reaction mixture was cooled to room temperature and filtered through a short silica gel column (washed with ethyl acetate). Subsequently, the solvent was removed under reduced pressure to give the crude product, which was finally purified by silica gel column chromatography to give the target product diphenylmethyl diethyl phosphite.
