Sulfuric Acid → HCID 22796788, compound

Participants

Reaction Steps

To a solution of 5.0 g. (13.32 mmol) of 2(S)-[2(R)-hydroxy-3-pentynyl]-2,5,7,8-tetramethyl-6-benzyloxy-chroman in 50 ml. of dry ether was carefully added 4.06 ml. of sodium bis(2-methoxyethoxy)-aluminum hydride (29 mg. - atm. of hydrogen) in 10 ml. of dry ether. The resulting solution was refluxed under argon for 17 hours. The solution was cooled in an ice bath and 10% by volumn aqueous H2SO4 solution (100 ml.) was carefully added. It was filtered, washed with ether and water. The aqueous phase was again extracted with ether (3 × 100 ml.). The combined ether phase was washed with saturated aqueous NaHCO3 solution (3 × 50 ml.) and water (3 × 50 ml.) and dried over MgSO4. Evaporation of ether to dryness at reduced pressure yielded 5.206 g. of crude product which was crystallized from petroleum ether (b.p. 30°-60° C.) to give 4.23 g. of 2(S)-[2(R)-hydroxy-3(E)-pentynyl]-2,5,7,8-tetramethyl-6-benzyloxychroman as white needles, m.p. 68°-70° C. [α]D25 -24.02° (CHCl3).

Provenance & Evidence