In a 3-neck round bottom flask, coupled with a reflux apparatus, 600 ml of dimethylsulfoxide were added under inert atmosphere along with a magnetic stirrer. The copper cyanide (265 mmol, 1.6 eq, 24.25 g) was then added, and the solution was warmed up to 50 °C for 30 mins to ensure the copper cyanide was dissolved. Then compound 2 (166 mmol, 1 eq, 38.94 g) was added dropwise while the mixture was still at 50 °C and then, the temperature was increased to 140 °C, allowing it to react overnight. Afterwards, the reaction was cooled down to room temperature and 200 ml of a 30% (w/w) of ammonia solution were slowly added. The mixture was diluted with distilled water to a final volume of 1200 ml and a distinctive a b c d e f dark blue color solution was obtained. This solution was washed several times with ethyl acetate (300 ml per washing), until the ethyl acetate washing was not getting colored (from dark yellow in the first washing to slightly colorless in the last). The organic layers were combined and dried over anhydrous MgSO4 and filtered, then the solvent was evaporated, and a dark brown oil remained. The purification was performed by column chromatography, using a mixture of cyclohexane: ethyl acetate (9:1) as the eluent. Compound 3 was obtained as a dark yellow oil. Yield: 16.25 g, 51%.