To a suspension of 2-3 (12.7 g, 63.2 mmol) was added a solution of 9-BBN in THF (132 mL of a 0.5 M solution, 65.8 mmol). After stirring for 15 hours, potassium carbonate powder (14.5 g, 105 mmol) and 2-3 (12.7 g, 52.7 mmol) was added. To this mixture was then added a premixed, degassed, aged (80° C. for 30 minutes with vigorous stirring) suspension of Pd(OAc)2 (1.78 g, 7.9 mmol) and DPPF (4.96 g, 8.9 mmol) in DMF (50 mL) via a cannula, and the resulting mixture degassed with argon bubbling for 30 minutes. The mixture was then heated at 70° C. for 3 hours. Following cooling, the mixture was reduced to a thick slurry, diluted with ether, washed with water and brine. The organics were dried over MgSO4 and concentrated to give a brown oil. This residue was chromatographed on silica gel (40–60% EtOAc/hexanes) to give 2-4 (9.6 g) as a yellow solid.
