5,5'-Bis(trifluoromethyl)-2,2'-bipyridyl

Representative procedure for the hydration: A 4 mL vial is charged sequentially with 5,5’-bis(trifluoromethyl)- 2,2’-bipyridine (1, 2.9 mg, 10 µmol, 0.020 eq.), tris(acetonitrile)cyclopentadienylruthenium(II) hexafluorophosphate (2, 4.4 mg, 10 µmol, 0.020 eq.), a mixture of water/1-methyl-2-pyrrolidinone (1:4 v/v, 2.5 mL, deoxygenated by sparging with nitrogen), and (2-fluorophenyl)acetylene (60.0 mg, 500 µmol, 1 eq.). The vial is sealed with a Teflon-lined cap. The mixture is stirred for 8 h at 25 °C. The product mixture is transferred to a separatory funnel and diluted with ethyl acetate (20 mL). The organic layer is washed with brine (3 x 20 mL). The ethyl acetate layer is concentrated. The residue obtained is purified by flash-column chromatography (eluting with 1 % ethyl acetate–hexanes - 2 % ethyl acetate-hexanes) to provide (2-fluorophenyl)acetaldehyde as a clear, colorless oil (56.6 mg, 82%).