A solution containing the product from Example 3G (2.4 g, 10.43 mmol) in dichloromethane (24 mL) was treated with the product from Example 15A (1.3 g, 10.74 mmol) and MgSO4 (4.6 g, 38.21 mmol), stirred at 25° C. for 2.5 hours, filtered and concentrated. A solution of the residue in methanol (24 mL) at 0° C. was treated with sodium borohydride (0.5 g, 13.2 mmol), and stirred at 25° C. for 3 hours. The solvent was concentrated and the reaction was partitioned between ethyl acetate and saturated NaHCO3, and the organic phase was washed with brine and dried over MgSO4, filtered and concentrated. A solution of the residue (3.4 g) in 1,2 dichloroethane (30 mL was treated with bis(4-nitrophenyl) carbonate (3.8 g, 12.5 mmol), heated at 60° C. for 16 hours, and partitioned between ethyl acetate and saturated NaHCO3. The organic phase was washed with brine, dried over MgSO4, filtered and concentrated. The residue was chromatographed on silica gel eluting with ethyl acetate to give the title compound (2.31 g, 60% yield).
