The de-symmetrized intermediate 4 (24 g, 0.093 mol) was dissolved in acetonitrile (MeCN, 300 mL) and H2O (100 mL). The reaction was heated to 60 o C and a solution of KCN (9 g) in water (20 mL) was added slowly. The reaction was stirred at 60 o C for 3 hours and monitored by TLC every 30 minutes until all starting material was consumed. More KCN solution was added as needed. The solvent was removed in vacuo and brine (200 mL) was added to the reaction flask.