To a magnetically stirred solution of 0.119 mL (1.15 mmol) of triethylamine in 5 mL toluene was added 0.575 mL (1.15 mmol) of a 2.0 M solution of trimethylaluminum in toluene at 0° C. The reaction mixture was allowed to warm to room temperature and was stirred for 30 min. A solution of 0.300 g (0.57 mmol) of the product of Example 181 in 1 mL CH2Cl2 was added to the reaction mixture and when the addition was complete the reaction mixture was heated at 60° C. for 2 h. The reaction mixture was allowed to cool again to room temperature and was partitioned between EtOAc and 10% aq. NaHSO4. The organic extracts were combined, washed with water and brine, dried (Na2SO4), filtered and evaporated. The residue was purified on a silica gel flash chromatography column eluted with 0–30% EtOAc-hexane. Evaporation of the purified fractions and drying in vacuo afforded the titled compound. HPLC/MS: 550.0 (M+1), 551.8 (M+3); Rt=4.74 min.
