1,8-Diazabicyclo(5.4.0)undec-7-ene → 5-fluoro-8-methoxy-2H-chromene

Participants

Reaction Steps

6-Fluoro-2-hydroxy-3-methoxy-benzaldehyde (3.32 g, 19 mmol) was dissolved in acetonitrile (20 ml) and DBU (2.97 ml, 19 mmol) was-added followed by vinyltriphenylphosphine bromide (7.2 g, 19 mmol). The reaction mixture was heated under reflux for 48 h, diluted with water and extracted with ether (3×50 ml). The organic phase was washed with water, 10% sodium hydroxide, water and brine and evaporated in vacuo. The residue was submitted to column chromatography (silica gel, EA:Hex, 1:20) yielding 1.2 g of 5-fluoro-8-methoxy-2H-chromene (34%).

Provenance & Evidence