Evaluation of P-bridged biaryl phosphine ligands in palladium-catalysed Suzuki–Miyaura cross-coupling reactions

Abstract

Efficient palladium catalyst systems consisting of bench-stable biaryl phosphacycles and Pd(OAc)2 are described for Suzuki–Miyaura cross-coupling reactions of a diverse array of aryl halides and arylboronic acids.

Application of P‐Bridged Biaryl Phosphines in Pd‐Catalyzed α‐Arylation Reactions

“…[37,38] Without further purification, phobane[4.2.1]chloride 11 was treated with 2-biphenylmagnesium bromide solution to afford biaryl phobane ligand 7 as a white solid in 59 % isolated yield using a protocol reported previously in our laboratory [34] and by other authors. [39,40] Encouraged by the success of the Cg-based ligand 1 in Pdcatalyzed Suzuki-Miyaura [34,36] and borylation [33] reactions reported previously by our group, catalysts derived from this ligand were used to develop suitable reaction conditions for αarylation of p-bromoanisole (12) and propiophenone (13) (Table 1). The aryl ketone 14 was afforded in 72 % GC yield in the presence of Pd 2 (dba) 3 (1.0 mol %), biaryl phosphatrioxaadamantane 1 (1.5 mol %), and NaO t Bu (3.0 eq) in toluene at 40 °C for 12 h (entry 6).…”

“…As part of our ongoing research into understanding ligand structure‐activity relationships in Pd‐catalyzed cross‐coupling reactions, [33–36] we herein report the unprecedented application of the recently developed P ‐bridged biaryl phosphine ligands 1 and 6 in α ‐arylation of ketones using electronically and structurally diverse aryl bromides and chlorides under mild reaction conditions. Furthermore, we also introduce a new phobane ligand class, ligand 7 , derived from the asymmetrical phobane[4.2.1] framework.…”

Design, Synthesis and Characterization of Aurone Based α,β‐unsaturated Carbonyl‐Amino Ligands and their Application in Microwave Assisted Suzuki, Heck and Buchwald Reactions

“…2‐phenylquinoline (5 p) : [49] White Solid; Yield 91%; m. p 85–86 °C; 1 H NMR (400 MHz, CDCl 3 ) δ 8.22 (d, J =8.92 Hz, 1H), 8.16 (t, J =8.04 Hz, 3H), 7.87 (d, J =8.9 Hz, 1H), 7.82 (d, J =8.5 Hz, 1H), 7.72 (t, J =8.08 Hz, 1H), 7.53 (t, J =7.9 Hz, 3H), 7.47 (d, J =7.6 Hz, 1H); 13 C NMR (100 MHz, CDCl 3 ) δ 157.50, 148.37, 139.78, 136.90, 129.81, 129.76, 129.39, 128.93, 127.67, 127.56, 127.27, 126.36, 119.14.…”

“…Chromen-2-one (5 n): [47] White solid; Yield 86%; m. p 99-100 °C; (5 o): [48] White Solid; Yield 79%; m. p 182-183 °C; 1 H NMR (400 MHz, CDCl 3 ) 8.10 (d, J = 6.64 Hz, 2H), 7.83 (d, J = 12.52 Hz, 1H), 7.73 (d, J = 6.6 Hz, 2H), 7.66 (d, J = 6.00 Hz, 2H), 7.58-7.53 (m, 3H), 7.48 (t, J = 5.92 Hz, 2H), 7.41 (t, J = 5.96 Hz, 1H), 7.25-7.23 (m, 2H), 2.40 (s, 3H); 13 [49] [50] [50] White Solid; Yield 84%; m. p 59-60 °C;…”

Nickel-Catalyzed Direct Cross-Coupling of Diaryl Sulfoxide with Aryl Bromide

“…2-Phenylpyridine (3p). 20 Yield = 47%, 36.3 mg. White solid. 1 H NMR (400 MHz, CDCl 3 ): δ 8.67 (ddd, J = 4.7, 1.7, 0.9 Hz, 1H), 8.21 (dt, J = 7.9, 1.0 Hz, 1H), 8.09−8.04 (m, 2H), 7.93 (td, J = 7.8, 1.7 Hz, 1H), 7.64−7.59 (m, 1H), 7.53 (tt, J = 6.5, 1.6 Hz, 2H), 7.46 (ddd, J = 7.7, 4.7, 1.2 Hz, 1H) ppm.…”