Environmentally-Safe Conditions for a Palladium-Catalyzed Direct C3-Arylation with High Turn Over Frequency of Imidazo[1,2-b]pyridazines Using Aryl Bromides and Chlorides

Sabah Chikhi (1, 2) , Safia Djebbar (2, 1) , Jean-François Soulé (2) , Henri Doucet (2)

1 LHCIM - Laboratoire d'hydrométallurgie et chimie inorganique moléculaire
2 ISCR - Institut des Sciences Chimiques de Rennes

Pd(OAc)2 was found to catalyze very efficiently the direct arylation of imidazo[1,2-b]pyridazine at C3-position under a very low catalyst loading and phosphine-free conditions. The reaction can be performed in very high TOFs and TONs employing as little as 0.1–0.05 mol % catalyst using a wide range of aryl bromides. In addition, some electron-deficient aryl chlorides were also found to be suitable substrates. Moreover, 31 examples of the cross couplings were reported using green, safe, and renewable solvents, such as pentan-1-ol, diethylcarbonate or cyclopentyl methyl ether, without loss of efficiency.

Mots clés: Aromatic compounds; Chemical reactions; Catalysts; Chlorine compounds; Palladium; Phosphorus compounds; Aryl halides; Cyclopentyl methyl ethers; Environmentally safe; Green solvents; Heterocycles; Loss of efficiencies; Palladium-catalyzed; Phosphine-free; Metal halides

Domaines: Chimie

Sabah Chikhi, Safia Djebbar, Jean-François Soulé, Henri Doucet. Environmentally-Safe Conditions for a Palladium-Catalyzed Direct C3-Arylation with High Turn Over Frequency of Imidazo[1,2-b]pyridazines Using Aryl Bromides and Chlorides. Chemistry , 2016, 11 (17), pp.2443--2452. ⟨10.1002/asia.201600827⟩. ⟨hal-01367228⟩