Palladium-Catalysed Direct Arylation of Heteroaromatics Bearing Unprotected Hydroxyalkyl Functions using Aryl Bromides

International audienceHeteroaromatics bearing unprotected hydroxyalkyl functions can be arylated using aryl or heteroaryl bromides, via palladium-catalysed carbon-hydrogen bond activation/arylation. Good yields were generally obtained using 0.01-0.5 mol% of the air-stable palladium acetate complex as the catalyst. The nature of the base was found to be crucial for the selectivity of this reaction. Potassium acetate led to the direct arylation products whereas caesium carbonate led to the formation of the ether. This procedure is certainly more atom-economic than other methods for the preparation of such compounds, as no protection/deprotection sequence of the hydroxyalkyl function and no preparation of an organometallic derivative is required

Preparation of hexacoordinating benzimidazole containing ligand and hexakis(benzimidazole-ruthenium(II)) complex. Molecular structure of C6{CH2-(N-benzimidazole-RuCl2(p-cymene))}6.

International audienceA hexabenzimidazole ligand was synthesised and used to prepare a hexakis{benzimidazole-ruthenium(II)} complex containing six RuCl(2)(arene) units of which the X-ray structure analysis shows a helical arrangement with alternating up and down benzymidazole-ruthenium(II) branches attached to a central benzene ring. The reactivity of the prepared complex with phosphite and carbonate was investigated and revealed the weakness of (benzimidazole)N-Ru bonds and the release of the polydentate ligand

ISHC XVI

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