ИСТИНА

The cage-like structures based on metallsesquioxanes are attracted the attention of many research groups because they demonstrate intriguing catalytic properties [1]. In recent years the Chan-Evans-Lam (CEL) coupling reaction, copper-catalyzed interaction of H-nucleophiles (amines, amides, carbamates, phenols etc.) and boronic acids, became popular instrument of fine organic synthesis [2]. Here we show that several copper-based cage-like silsesquioxanes catalyze coupling of boronic acids and carboxylic acids under microwave (MW) conditions. In comparison to published results [3a-e], Cu4Na4 complex (Fig. 1) exhibit high catalytic activity on conditions of low loading of copper source and added base [4]. To the best of our knowledge, this is a first example of CEL reaction by making C-O bond in MW. Work was supported by RFBR (project 19-03-00488) References [1] (a) Coord. Chem. Rev., 2016, 306, 235-269; (b) Catalysts, 2019, 9, 154; (с) Inorg. Chem., 2018, 57, 11524-11529; (d) J. Mol. Catal. A : Chem., 2017, 426 (Part B), 297–304; (d) Angew. Chem. Int. Ed., 2016, 55, 15360-15363 [2] (a) J. Am. Chem. Soc., 2018, 140, 5579−5587; (b) J. Am. Chem. Soc., 2017, 139, 4769−4779; (c) ACS Catal., 2018, 8, 9560–9566; (d) Adv. Synth. Catal., 2018, 360, 1510-1516; (e) Adv. Synth. Catal., 2018, 360, 4241-4245 [3] (a) J. Org. Chem., 2015, 80, 7305-7310; (b) J. Org. Chem, 2010, 75, 7472-7474; (c) Chem. Comm., 2011, 47, 677-679; (d) Org. Chem. Front., 2018, 5, 2322-2331; (e) Tetrahedron Lett., 2014, 55, 2345-2347 [4] G. S. Astakhov, A.N. Bilyachenko, F. Lamaty et al. (in preparation).