3-Fluoro-2-hydroxybenzaldehyde (CAS number 394-50-3), also known as 3-Fluorosalicylaldehyde, is a benzaldehyde derivative with a fluorine at 3-position and a hydroxy at 2-position. 3-Fluoro-2-hydroxybenzaldehyde is commonly used to synthesize salen (salicylaldehyde and ethylenediamine) ligands as tetradentate C2-symmertic ligands. Cobalt-salen complexes based on 3-fluoro-2-hydroxybenzaldehyde show reversible oxygen chemisorption as well as anticancer activity with IC50 (half maximal inhibitory concentration) of 50 µM.
By having three chemically reactive sites, 3-fluoro-2-hydroxybenzaldehyde is used to synthesize fluorinated bicyclic heterocycles such as isoflavanone (chromanone) through gold(I) catalyzed annulation reaction. Semiconducting acenes can also be prepared from 3-fluoro-2-hydroxybenzaldehyde.