Cyclometallated gold(III) aryl-pyridine complexes as efficient catalysts for three-component synthesis of substituted oxazoles

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 44; no. 12; pp. 5347 - 5353
• Main Authors: von Wachenfeldt, Henrik, Polukeev, Alexey V, Loganathan, Nagarajan, Paulsen, Filip, Röse, Philipp, Garreau, Marion, Wendt, Ola F, Strand, Daniel
• Format: Journal Article
• Language: English
• Published: England 01.01.2015
• Subjects: Alkynes; Catalysis; Catalysts; Chemical Sciences; Chlorides; Diffraction; Imines; Kemi; Natural Sciences; Naturvetenskap; Oxazole; X-rays
• ISSN: 1477-9226; 1477-9234; 1477-9234
• DOI: 10.1039/c4dt03806a

Cyclometallated aryl-pyridine gold(iii) complexes are shown to be efficient catalysts for the multicomponent reaction between N-benzyl imines, alkynes, and acyl chlorides to form trisubstituted oxazoles. The reaction typically proceeds in good yields (up to over 80%) and short reaction times (∼15 minutes). The high stability of the investigated cyclometallated catalysts enables a retained efficiency for this reaction in terms of rate and yield using as little as 0.5 mol% catalyst, a reduction by an order of magnitude compared to previously used Au(iii)-salen complexes. An attractive feature of the present catalytic system is that active catalysts can be formed from simple pre-catalysts under the reaction conditions. Both cyclometallated and non-cyclometallated complexes were characterized in the solid state by single crystal X-ray diffraction.