Evaluation of catalytic properties of aminocarbene species derived from the integration between 3-iminoisoindolin-1-ones and palladium-bound isonitriles in Suzuki–Miyaura cross-coupling

A series of palladium aminocarbene complexes [PdCl{C(NC(C6R2R3R4R5CON))N(H)R1}(CNR1)] (9–23, 80–85% isolated yield) were obtained via the metal-mediated integration of one isonitrile in cis-[PdCl2(CNR1)2] [R1 = Cy 1, t-Bu 2, Xyl 3, 2-Cl,6-Me-C6H3 4] and various 3-iminoisoindolin-1-ones [R2–R5 = H 5; R2, R4, R5 = H, R3 = Me/R2, R3, R5 = H, R4 = Me 6 (isomeric mixture); R2, R5 = H, R3, R4 = Cl 7; R2–R5 = F 8]. New compounds 18–23 were completely characterized using (C, H, N), ESI+–MS, IR, 1D (1H, 13C{1H}) and 2D (1H,1H COSY, 1H,13C HMQC/1H,13C HSQC, 1H,13C HMBC) NMR spectroscopies. ficiency of all prepared aminocarbene species 9–23 in Suzuki–Miyaura cross-coupling reaction of aryl-bromides and iodides was evaluated, showing that complexes 9, 14 and 21 manifest the highest activity furnishing the coupling product in 81–99% yield, and giving maximum turnover numbers (TONs) up to 7.6 × 104. Catalytic system employs non-dried EtOH as an environmentally benign solvent, K2CO3 as a base, and runs under air.