At −78° C., t-BuLi in THF (1.7 M, 0.34 mL, 0.58 mmol) was added to a solution of trityl protected compound (d) (116 mg, 0.289 mmol) in THF. Then 3,4,5-trimethoxybenzoyl chloride (66.5 mg, 0.289 mmol) was added and stirred overnight. The reaction mixture was quenched with saturated NH4Cl, and dried with MgSO4. Filtration and evaporation of the solvent followed by chromatography afforded compound (e) (75 mg, 43.7%). 1H NMR (500 MHz, CDCl3) δ 7.55-7.41 (m, 5H), 7.32 (s, 1H), 7.28-7.18 (m, 15H), 6.94 (s, 2H), 3.78 (s, 6H), 3.70 (s, 3H). MS: 594.2 (M−H)−; 596.3 (M+H)+.
