Synthesis of Terphenyl Derivatives by Pd‐Catalyzed Suzuki‐Miyaura Reaction of Dibromobenzene Using 2N2O‐Salen as a Ligand in Aqueous Solution

Abstract

A simple and efficient catalytic system for Na2PdCl4 catalyzing the Suzuki‐Miyaura reaction of dibromobenzene and arylboronic acid has been developed by using 2N2O‐salen as a ligand in H2O/EtOH (V:V=4:1) at 100°C. Using this method, the reactions of substrates containing sterically demanding ortho substituents (e.g. dibromobenzene and/or arylboronic acids) proceeded efficiently, with the corresponding terphenyl derivatives being produced in moderate to excellent yields. Furthermore, this method offers interesting features for the multi‐gram scale synthesis of terphenyl compound.

Synthesis of N‐Heterocyclic Carbene–PdII–2‐Methyl‐4,5‐dihydrooxazole Complexes and Their Application Toward Highly Chemoselective Mono‐Suzuki–Miyaura Coupling of Dichlorobenzenes

“…Compound 7 b : Colorless liquid; 1 H NMR (CDCl 3 , 500 MHz): δ =7.45–7.42 (m, 1 H), 7.30–7.23 (m, 11 H), 2.31 ppm (s, 6 H); 13 C NMR (CDCl 3 , 125 MHz): δ =141.8, 141.7, 135.3, 130.3, 130.1, 129.8, 127.8, 127.6, 127.3, 125.8, 20.5 ppm.…”

“…Compound 7 c : Colorless liquid; 1 H NMR (CDCl 3 , 500 MHz): δ =7.78 (s, 1 H), 7.54 (d, J= 8.0 Hz, 2 H), 7.48–7.43 (m, 5 H), 7.33 (t, J= 7.5 Hz, 2 H), 7.17 (d, J= 7.5 Hz, 2 H), 2.42 ppm (s, 6 H); 13 C NMR (CDCl 3 , 125 MHz): δ =141.9, 141.3, 138.3, 129.0, 128.7, 128.1, 128.0, 126.2, 126.0, 124.4, 21.5 ppm.…”

“…Compound 7 m : White solid; 1 H NMR (CDCl 3 , 500 MHz): δ =7.79 (s, 1 H), 7.74–7.72 (m, 8 H), 7.63 (d, J= 7.5 Hz, 2 H), 7.60–7.57 ppm (m, 1 H); 13 C NMR (CDCl 3 , 125 MHz): δ =144.4, 140.7, 129.8 (q, J= 32.1 Hz), 1129.7, 127.5, 127.1, 126.3, 125.8 (q, J= 3.7 Hz), 124.3 ppm (q, J= 270.3 Hz).…”

“…Compound 7 p : White solid; 1 H NMR (CDCl 3 , 500 MHz): δ =7.68 (s, 4 H), 7.65 (d, J= 8.0 Hz, 4 H), 7.46 (t, J= 7.5 Hz, 4 H), 7.36 ppm (t, J= 7.5 Hz, 2 H); 13 C NMR (CDCl 3 , 125 MHz): δ =140.7, 140.1, 128.8, 127.5, 127.3, 127.0 ppm.…”

Metal‐Free Synthesis of Thermally Stable Fluorescent p‐Terphenyls by Ring Transformation of 2H‐Pyran‐2‐ones

“…[27][28][29][30][31] Furthermore, the water-soluble 2 N 2 O-salen was used as an efficient ligand to construct pterphenyl scaffolds via Pd-catalyzed Suzuki-Miyaura coupling of dibromobenzene with different aryl boronic acids. [32] In 2013, Wang and others developed the synthesis of p-terphenyls by Pd-catalyzed Stille cross-coupling of boron and tin-cored substrates with aryl bromide followed by Pd-catalyzed Suzuki-Miyaura cross-coupling of earlier coupling product with aryl bromide. [33] In 2018, Takahashi and coworkers reported the synthesis naturally occurring p-terphenyl (polyozellin) in five chemical steps in including Pd-catalyzed Suzuki-Miyaura crosscoupling reaction.…”