Hydroxymethyl as Directing Group for the Regioselective Palladium-Catalyzed C–H Bond C2-Arylation of a C3-Substituted Furan

Abstract The reaction outcome of the palladium-catalyzed C–H arylation of 3-(hydroxymethyl)furan was investigated. The hydroxymethyl group at the C3 position of the furan proved to be a powerful directing group for controlling regioselective direct arylation at the C2 position, while the C5-position and the hydroxymethyl function of the furan ring remained unaffected. The reaction tolerates a very wide variety of electron-poor or rich aryl bromides, bearing substituents at the para- or meta-positions, as well as heteroaryl bromides. It should be noted that, for this coupling reaction, an air-stable palladium catalyst and an inexpensive base were used. Using an excess of specific aryl bromides, 3-(hydroxymethyl)furan can also be diarylated at positions 2 and 5.