Divalent Heteroleptic Ytterbium Complexes – Effective Catalysts for Intermolecular Styrene Hydrophosphination and Hydroamination
datasetposted on 03.02.2014, 00:00 by Ivan V. Basalov, Sorin Claudiu Roşca, Dmitry M. Lyubov, Alexander N. Selikhov, Georgy K. Fukin, Yann Sarazin, Jean-François Carpentier, Alexander A. Trifonov
New heteroleptic Yb(II)–amide species supported by amidinate and 1,3,6,8-tetra-tert-butylcarbazol-9-yl ligands [2-MeOC6H4NC(tBu)N(C6H3-iPr2-2,6)]YbN(SiMe3)2(THF) (6) and [1,3,6,8-tBu4C12H4N]Yb[N(SiMe3)2](THF)n (n = 1 (7), 2 (8)) were synthesized using the amine elimination approach. Complex 6 features an unusual κ1-N,κ2-O,η6-arene coordination mode of the amidinate ligand onto Yb(II). Complexes 7 and 8 represent the first examples of lanthanide complexes with π-coordination of carbazol-9-yl ligands. Complexes 6 and 7, as well as the amidinate–Yb(II)–amide [tBuC(NC6H3-iPr2-2,6)2]YbN(SiMe3)2(THF) (5), are efficient precatalysts for the intermolecular hydrophosphination and hydroamination of styrene with diphenylphosphine, phenylphosphine, and pyrrolidine to give exclusively the anti-Markovnikov monoaddition product. For both types of reaction, the best performances were observed with carbazol-9-yl complex 7 (TONs up to 92 and 48 mol/mol at 60 °C, respectively).