Bis(trimethylsilyl)carbodiimide → N-(5-(3-cyanophenyl)-2',3',5',6'-tetrahydrospiro[indene-1,4'-pyran]-3(2H)-ylidene)cyanamide

To a solution of 3-(3-oxo-2,2′,3,3′,5′,6′-hexahydrospiro[indene-1,4′-pyran]-5-yl)benzonitrile (42 mg, 0.139 mmol) in anhydrous DCM (10 mL) under N2 atmosphere was added 1 M TiCl4 (in DCM, 0.28 mL, 0.28 mmol) dropwise within 15 min at room temperature. It was stirred another 1 h after the addition. To this mixture was added Bis-trimethylsilylcarbodiimide (0.1 mL, 0.427 mmol) dropwise. The resulting mixture was stirred overnight. The reaction mixture was quenched with ice-water (15 g), and stirred for 30 min, then it was transferred to a separating funnel, the separated aqueous phase was extracted 2 times with DCM. The combined organic phases were dried over anhydrous Na2SO4, and filtered, and concentrated to give the desired product as white solid, which was used for next step without further purification. MS ESI+ve m/z 328 (M+H)30.