Acetic Anhydride → (E)-(2S)-6-phenylhex-5-en-3-yn-2-yl acetate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a solution of alcohol 7 (400 mg, 2.32 mmol) in pyridine (pyridine was distilled over CaH2 and stored over KOH; 4.6 mL) at 23° C. was added acetic anhydride (1.10 mL, 11.6 mmol). The resulting mixture was stirred for 2 h at 23° C. The reaction was quenched by 1 N aqueous HCl (10 mL) at 0° C. and diluted with EtOAc (5 mL). The mixture was poured into a separatory funnel. The layers were separated and the aqueous layer was extracted with EtOAc (3×3 mL). The combined organic layers were washed with brine (5 mL), dried over Na2SO4, filtered, and concentrated in vacuo. Purification of the residue via flash chromatography (silica gel 40 mL; 5→30% EtOAc in hexanes) afforded acetate 8 (486 mg, 98%, 95% ee; the ee value was determined by HPLC ((S,S) Whelk; 25 cm, 1.0 mL/min, hexanes/iPrOH=95/5).) as a colorless oil.

Herkunft & Nachweise