36520-39-5

109-77-3

78797-58-7

Under nitrogen protection, 1,1-dicyanoethylene (500 mg, 4.2 mmol, 1.0 eq.) was dissolved in 5.0 mL of toluene in a 50 mL round bottom flask. Polymethylhydrosiloxane (PMHS, 1.0 mL, 16.8 mmol, 4.0 eq.) and tetraisopropyl titanate (Ti(Oi-Pr)4, 1.3 mL, 4.3 mmol, 1.0 eq.) were added sequentially. The reaction mixture was heated at 100 °C for 24 h. The reaction solution was observed to change from colorless to dark purple. After completion of the reaction, it was cooled to room temperature, the dark purple solution was diluted with 30 mL of toluene and hydrolyzed by adding 1 M aqueous hydrochloric acid (15 mL, 3.6 eq.) for 4 hours until the color of the solution changed from dark purple to yellow. The crude product was concentrated under reduced pressure and the resulting solid was collected by filtration and washed with 60 mL of pentane. Subsequently, the solid was dissolved in chloroform and filtered through a Celite pad. Finally, the filtrate was concentrated under reduced pressure to give the hydrochloride form of the target compound 3p.