(2S)-2-{[(R)-(4-bromophenyl)(phenyl)methyl]oxy}-N-(cyanomethyl)-4-methylpentanamide (1 g, 2.41 mmol) 1-[4-(dihydroxyboryl)phenyl]piperazin-4-ium chloride (642 mg, 2.65 mmol), PdCl2(dppf) (88 mg, 0.120 mmol) and 2M Na2CO3 (4.8 ml, 9.63 mmol) were dissolved in 25 ml DMF, the solution was degassed 3 times and heated for 10 h @ 85° C. The solution was cooled, poured into 125 ml NaHCO3 (sat.) and the product extracted with 3×25 ml ethyl acetate. The combined organic layers were then washed with 4× water, then dried with Na2SO4. The product was then purified on silica gel (5% MeOH/5% NH4OH/90% DCM).
