Formaldehyde → 5-(1-Hexenyl)-2-hydroxybenzaldehyde

Participants

Reaction Steps

NMR (200 MHz, DMSO-d6) (mixture of cis and trans isomers): δ9.33 (s, 1H), 7.14 (m, 2H), 6.70 (m, 2H), 6.26 (m, 1H), 6.1-5.35 (multiplets, together 1H), 2.35-2.08 (m, 2H), 1.36 (m, 4H), 0.89 (m, 3H). 4-(1-Hexenyl)phenol in toluene (8 ml) was added to Mg(OMe)2 (7.3 ml, 8% wt/wt solution in methanol, 5.5 mMol) and the resultant red solution heated at reflux for 1 hour. The mixture was then distilled until the reaction temperature rose to 95° C. A suspension of paraformaldehyde (0.78 g, 26 mmol) in toluene (5 ml) was then added and the reaction heated at reflux for three hours. The reaction was allowed to cool to ambient temperature and to stir overnight. The reaction mixture was then diluted with toluene and washed with 2M aqueous H2SO4 (10 ml). The organic layer was washed with water (3×), dried (MgSO4) and evaporated. The residue was purified by chromatography (eluant: ethyl ether/hexane) to give 5-(1-hexenyl)-2-hydroxybenzaldehyde as a yellow/green oil (0.65 g, 38%).

Provenance & Evidence