p-Toluenesulfonic acid → 2-Methyl-2-phenylpent-4-enal

Participants

Reaction Steps

A solution of 2-phenylpropionaldehyde (9.90 mL, 74.5 mmol), allyl alcohol (20.4 mL, 300 mmol) and p-toluene sulfonic acid (0.8560 g, 4.5 mmol) in benzene (37 mL) was heated to reflux for 19 hours and a Dean-Stark trap was used to collect the water formed. The mixture was cooled to room temperature and saturated aqueous NaHCO3 (5 mL) and H2O (5 mL) were added. The phases were separated and the organic layer was washed a second time with saturated aqueous NaHCO3 (5 mL) and H2O (5 mL). The organic layer was dried (MgSO4) and concentrated under reduced pressure. A solution of the resultant yellow residue in p-xylene (150 mL) was heated to reflux for 24 hours. The solution was cooled to room temperature and concentrated under reduced pressure. The resultant aldehyde (13.0 g) was used in the next reaction without further purification.

Provenance & Evidence