Acetylation of cis-Allylic Alcohols – DMAP as Catalyst

P.A. Grieco, P.A. Tuthill, and H.L. Sham, J. Org. Chem., 46, 5005 (1981)

1. A solution of the alcohol (1) (220 mg, 0.473 mmol), acetic anhydride (1.0 mL), and pyridine (0.5 mL) in dry dichloromethane (5.0 mL) is prepared.
2. DMAP (catalytic amount) is added and the reaction mixture stirred at ambient temperature for 24 h.
3. The reaction mixture is diluted with ether (50 mL) and then is washed successively with copper sulfate solution, water, sodium bicarbonate solution, and brine.  The organic phase is dried (anhydrous magnesium sulfate), filtered, and evaporated to afford a residue (210 mg).  The residue is purified on silica gel (40 g) eluting with hexane:ethyl acetate (15:1) to give, after solvent evaporation, the pure acetate (2) (196 mg, 82%) as a colorless oil.