4-Toluenesulfonyl chloride → (R)-(-)-2,2-Dimethyl-1,3-dioxolan-4-ylmethyl p-Toluenesulfonate

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Reaction Steps

p-Toluenesulfonyl chloride (6.5 g, 34.1 mmol) was added portionwise over a period of 10 min to a solution of (S)-(+)-1,2-isopropylideneglycerol (3.0 g, 22.7 mmol) and DMAP (30 mg, 0.25 mmol) in anhydrous pyridine (30 mL) in a water bath. The resulting solution was stirred overnight. The pyridine was removed under reduced pressure, and the residue was diluted with ethyl acetate (50 mL), washed subsequently with water (2×40 mL), cold aqueous 1 M HCl (40 mL), saturated NaHCO3 (40 mL) and water (40 mL). The organic layer was dried over Mg2SO4, filtered and concentrated to give a light yellow oil. The crude product was purified by column chromatography (eluent: 10% ethyl acetate in hexane to 30% ethyl acetate in hexane) to afford (R)-2,2-Dimethyl-1,3-dioxolane-4-methanol p-toluenesulfonate i (5.91 g, 90.9% yield) as a colorless viscous oil.

Provenance & Evidence