To a solution of Example 1B (200 g, 0.614 mol) in anhydrous toluene/THF (1.2 L, 2:1 (v/v)) was added n-BuLi (2.5 M in hexane, 295 mL) dropwise at −65° C. The reaction was stirred at −65° C. for 30 min. Then the mixture was transferred by a cannula to a solution of (3R,4S,5R,6R)-3,4,5-tris(trimethylsilyloxy)-6-((trimethylsilyloxy)methyl)tetrahydro-2H-pyran-2-one) (373 g, 0.798 mol) in toluene (1.2 L) at −65° C. The mixture was stirred at −65° C. until starting material was consumed (2 h). The reaction was quenched with hydrochloric acid (36˜38%, 113 mL, 1.35 mol) in methanol (800 mL), and stirred at room temperature overnight. The reaction was neutralized with saturated sodium bicarbonate to pH 7.5 and the organic phase was separated and the aqueous phase was extracted with ethyl acetate (2×3.0 L). The combined organic layers were washed with brine (2×2.0 L), dried over sodium sulfate and concentrated. The residue was dissolved in hot toluene (600 mL) and poured into n-hexane (2.0 L) with vigorous stirring. After stirring for 1 h, the mixture was filtered and the filter cake was dried under vacuum to give the desired product as a white solid. This solid was used without further purification in the next step. MS ESI (m/z) 439 [M+1]+.
