Cu(II)-silsesquioxanes as efficient precatalysts for Chan-Evans-Lam coupling

G.S. Astakhov (1) , M.M. Levitsky (1) , Xavier Bantreil (2) , Frédéric Lamaty (2) , V.N. Khrustalev (3) , Y.V. Zubavichus (4) , P.V. Dorovatovskii (5) , E.S. Shubina (1) , A.N. Bilyachenko (3, 1)

1 INEOS - A. N. Nesmeyanov Institute of Organoelement Compounds
2 IBMM - Institut des Biomolécules Max Mousseron [Pôle Chimie Balard]
3 RUDN - Peoples Friendship University of Russia [RUDN University]
4 Boreskov Institute of Catalysis
5 NRC KI - National Research Center "Kurchatov Institute"

Two cage copper(II)silsesquioxanes, namely, tricopper complex (PhSiO 1.5) 8 (CuO) 3 (TMEDA) 2 *(MeCN) 3 Cu-1 and hexacopper complex (MeSiO 1,5) 12 (CuO) 6 (Py) 6 *TMEDA Cu-2 were synthesized (in 30% and 16% yield, respectively) via TMEDA-assisted reactions (TMEDA ¼ tetramethylethylenediamine). Structural features of both products were established by X-ray diffraction study. Complexes Cu-1 and Cu-2, along with some Cu(II)-silsesquioxanes reported earlier, were evaluated for the first time as precatalysts for the homogeneous Chan-Evans-Lam (CEL) O-arylation of benzoic acids (the highest yield of phenylbenzoic ester was 84%). Observed catalytic activity was superior to reference catalyst Cu(OAc) 2 *H 2 O. Finally, an application of coppersilsesquioxanes allowed to observe the first example of CO CEL coupling under microwave activation characterized by (i) reduced loading of copper, (ii) low amount of added base, (iii) minimization of the time of reaction.

Mots clés: Copper complexes; Chan-Evans-Lam coupling; Metallasilsesquioxanes; X-ray

Domaines: Chimie de coordination; Catalyse; Chimie organique

G.S. Astakhov, M.M. Levitsky, Xavier Bantreil, Frédéric Lamaty, V.N. Khrustalev, et al.. Cu(II)-silsesquioxanes as efficient precatalysts for Chan-Evans-Lam coupling. Journal of Organometallic Chemistry, 2020, 906, pp.121022. ⟨10.1016/j.jorganchem.2019.121022⟩. ⟨hal-02389969⟩