A solution of 1.55 g (3.93 mmol) of the product from Step A in toluene (20 mL) was treated with ethyl glycolate (0.41 mL; 4.33 mmol) and cesium carbonate (2.54 g; 7.8 mmol). The reaction mixture was heated in a sealed pressure tube at 80° C. and stirred for 6 h. The reaction mixture was cooled to room temperature and partitioned between ethyl acetate and saturated NaHCO3 solution. The organic layer was washed twice with saturated NaHCO3 solution, brine, dried (Na2SO4), filtered, and concentrated in vacuo. Purification by MPLC (silica gel; 0% to 20% ethyl acetate:hexane gradient) gave the title compound. HPLC/MS: 460.9 (M+1), 462.9 (M+3); Rt=4.50 min.
