To a mixture of 2-(4-(2-(allyloxy)ethyl)benzyl)-4-bromo-1-chlorobenzene (intermediate BI) (123 mg, 0.34 mmol) and (3R,4S,5R,6R)-3,4,5-tris(benzyloxy)-6-(benzyloxymethyl)tetrahydro-2H-pyran-2-one (362 mg, 0.67 mmol) in anhydrous THF (1.5 mL) under argon and kept at −78° C. was added dropwise a 1.6 M solution of n-butyl lithium in hexane (0.63 mL) over 15 min. The mixture was stirred at −78° C. for 1.5 h. A solution of methanesulfonic acid (0.1 mL) in methanol (1 mL) was added to the reaction mixture and allowed to warm to room temperature over time. The mixture was stirred at room temperature for 21 h. A saturated solution of sodium bicarbonate was slowly added to the reaction mixture to bring the pH to 8. Water (2 mL) was added and the product was extracted into ethyl acetate (3×2 mL), the combined ethyl acetate solution was washed with brine (1.5 mL), dried (Na2SO4), filtered and evaporated. Preparative thin layer chromatography (TLC) using 12:1 hexane:EtOAc gave intermediate BJ (80 mg, yield 28%). LC-ESI-MS (m/z): 807 (M−OMe).
