2,3‐Bis[( <i>R</i> )‐(1,1‐dimethylethyl)methylphosphino]‐Quinoxaline

Abstract image [ 866081‐62‐1 ] C 18 H 28 N 2 P 2 (MW 334.38) InChI = 1S/C18H28N2P2/c1‐17(2,3)21(7)15‐16(22(8)18(4,5)6)20‐14‐12‐10‐9‐11‐13(14)19‐15/h9‐12H,1‐8H3/t21‐,22‐/m0/s1 InChIKey = DRZBLHZZDMCPGX‐VXKWHMMOSA‐N (reagent may be used as a chiral ligand for rhodium, palladium, copper, and silver complexes to perform enantioselective reductions, conjugate additions, and allylic alkylations) Alternate Name: QuinoxP*. Physical Data: mp 102–103°C; [α] D −54.3° ( c 1.00, CHCl 3 ); 1 H NMR (395.75 MHz, CDCl 3 ) δ 1.00–1.03 (m, 18 H ), 1.42–1.44 (m, 6 H ), 7.70–7.74 (m, 2 H ), 8.08–8.12 (m, 2 H ); 13 C NMR (99.45 MHz, CDCl 3 ) δ 4.77 (t, J = 4.1 Hz), 27.59 (t, J = 7.4 Hz), 31.90 (t, J = 7.4 Hz), 129.50, 129.60, 141.63, 165.12 (dd, J = 5.7, 2.4 Hz); 31 P NMR (202.35 MHz, CDCl 3 ) δ−17.7 (s); IR (KBr) 2950, 1470, 780 cm −1 ; HRMS (FAB) calcd. for C 18 H 29 N 2 P 2 (M + + H); 335.1809; found: 335.1826. Anal. calcd. for C 18 H 28 N 2 P 2 : C, 64.66; H, 8.44. Found: C, 64.57; H, 8.29. 1 Solubility: sol toluene, ether, THF, dichloromethane, hexane. Form Supplied in: orange solid; commercially available. Preparative Methods: a solution of n ‐BuLi (1.25 mL of 1.60 M hexane solution, 2.0 mmol) was added dropwise to a stirred solution of t ‐butylmethylphosphine–borane (236 mg, 2.0 mmol) in THF (4 mL) at −78 °C under nitrogen. After 15 min, a solution of 2,3‐dichloroquinoxaline (133 mg, 0.67 mmol) in THF (4 mL) was added in one portion with vigorous stirring and the mixture was warmed to rt during 1 h. After stirring for additional 3 h, tetramethylethylenediamine (1 mL) was added and stirring was continued for 2 h. The reaction was quenched with 1 M HCl and the mixture was extracted with hexane. The combined extracts were washed with 1 M HCl and brine, and dried over Na 2 SO 4 . The solvent was removed in vacuum and the residue was purified by chromatography on silica gel (hexane/EtOAc = 30/1) to give the desired product (179 mg, 8%) as an orange solid, which was further purified by recrystallization from hot MeOH (1.7 mL) to give orange cubes. 1 Handling, Storage, and Precautions : stable to air and moisture for more than 8 months.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.