Tris(1,1-dimethylethyl)phosphine → N-(1,1'-Biphenyl)-2-yl-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi(9H-fluoren)-2-amine

Participants

Reaction Steps

Tri-tert-butylphosphine (4.4 ml of a 1.0 M solution in toluene, 4.4 mmol), palladium acetate (248 mg, 1.1 mmol) and sodium tert-butoxide (16.0 g, 166 mmol) are added to a solution of biphenyl-2-yl-(9,9-dimethyl-9H-fluoren-2-yl)amine (40.0 g, 111 mmol) and 2-bromo-9,9′-spirobifluorene (56.9 g, 144 mmol) in degassed toluene (500 ml), and the mixture is heated under reflux for 2 h. The reaction mixture is cooled to room temperature, diluted with toluene and filtered through Celite. The filtrate is evaporated in vacuo, and the residue is crystallised from ethyl acetate/heptane. The crude product is extracted in a Soxhlet extractor (toluene) and purified by zone sublimation in vacuo twice (p=3×104 mbar, T=298° C.). Biphenyl-2-yl-(9,9-dimethyl-9H-fluoren-2-yl)-(9,9′-spirobifluoren-2-yl)amine is isolated in the form of a pale-yellow solid (20.4 g, 27% of theory, purity >99.99% according to HPLC).

Provenance & Evidence