Preparation and application of 2-(2-dicyclohexylphospha NYL-phenyl)-1-methyl-1H-indole_Industrial additives

Background and overview^[1]

2-(2-Dicyclohexylphospha NYL-phenyl)-1-methyl-1H-indole is an organophosphine ligand commonly used in Suzuki-Miyaura coupling reactions. 2-(2-Dicyclohexylphospha NYL-phenyl)-1-methyl-1H-indole can be prepared in one step from N-methyl-2-phenyl-3-bromoindole and chlorodicyclohexylphosphine .

Preparation^[1]

Dissolve N-methyl-2-phenyl-3-bromoindole (0.855 g, 3.0 mmol) in freshly distilled THF (20 mL) at room temperature under nitrogen atmosphere. Cool the solution to -78°C in a dry ice/acetone bath. Titrated n-butyllithium (3.3 mmol) was added dropwise via syringe. After the reaction mixture was stirred at -78 °C for 30 min, a solution of chlorodicyclohexylphosphine (0.66 mL, 3.3 mmol) in THF (5 mL) was added. The reaction was allowed to warm to room temperature and stirred overnight. Organobentonite rheology additive Remove the solvent under reduced pressure. After the solvent was removed in vacuo, the product was washed successively with a cold MeOH/EtOH mixture and then dried in vacuo. The product is 2-(2-dicyclohexylphospha NYL-phenyl)-1-methyl-1H-indole, a white solid (0.85 g, 71%). Melting point: 122.0-123.2°C. ¹H NMR ( MHz, C6D6) δ1.19-2.55 (m, 22H), 3.08 (s, 3H), 7.19-7.39 (m, 6H), 7.51 (d, J=7.3 Hz , 2H), 8.16-8.18 (m, 1H);¹³C NMR (100 MHz, CDCl₃) δ 26.8, 27.3, 27.5 (overlapped), 27.6, 30.7 133 .3 (overlapped), 138.8 ( overlapped), 149.8, 150.2(unresolved complex C-P splittings were observed); ³¹P NMR (162 MHz, C6D6) δ -18.36; IR(cm^-1) 3049.36, 2921.78, 2845.98, 1465.12, 1443.10, 1372.54, 1336.47, 1264.83, 1106.31,1021.29, 887.02, 849.63, 795.91, 737.94, 698.91, 61 9.86, 550.50; MS (EI): m/z (relative

intensity) 403(M+, 25), 348 (5), 321 (30), 238 (100), 222 (25), 207 (10); HRMS: calcd. forC27H34NPH⁺ : 404.2507, found 404.2511.

Apply^[1]

Chau Ming So et al. used the indolylphosphine ligand family such as 2-(2-dicyclohexylphospha NYL-phenyl)-1-methyl-1H-indole for aryl tosylate esters Suzuki-Miyaura cross-coupling. For the coupling of unactivated aryl tosylate, the catalyst loading can be reduced to 0.2 mol%.