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10 For the preparation of 1b and 1c, see ref. 9.
Representative Procedure for the Preparation of 1a: A solution of 2-bromo-1,1-diphenylpropene9 (25.0 g, 91.5 mmol) and magnesium turnings (2.35 g, 96.1 mmol) in THF (100 mL) was stirred at r.t. under a nitrogen atmosphere. After addition of a piece of iodine, the solution was refluxed for 2 h. Then chlorodiisopropylphosphine (16.8 g, 109.8 mmol) was added dropwise at the same temperature and the mixed solution was refluxed for 18 h. After cooling to r.t., H2O was added to the solution and the organic phase was extracted with toluene. The extract was dried over anhyd MgSO4 and concentrated under reduced pressure. The concentrate was purified by recrystallization from MeOH (100 mL) to give the title compound (18.8 g, 66%) as a white solid. 1H NMR (300 MHz, CDCl3): δ = 1.07 (dd, J = 2.0, 7.1 Hz, 6 H), 1.12 (dd, J = 5.7, 6.3 Hz, 6 H), 1.80-2.04 (m, 2 H), 1.86 (d, J = 2.1 Hz, 3 H), 7.08-7.33 (m, 10 H). 13C NMR (75 MHz, CDCl3): δ = 17.2 (d, J = 4.6 Hz), 20.8 (d, J = 1.1 Hz), 21.0 (d, J = 8.0 Hz), 24.4 (d, J = 14.3 Hz), 126.4, 126.5, 127.5, 128.1, 128.6, 130.2 (d, J = 3.5 Hz), 133.4 (d, J = 21.8 Hz), 143.5 (d, J = 8.6 Hz), 143.9 (d, J = 10.3 Hz), 155.3 (d, J = 32.0 Hz). 31P NMR (121 MHz, CDCl3): δ = 5.44. HRMS (ESI): m/z [M + H]+ calcd for C21H27P: 311.1929; found: 311.1916.
11 Ligands 1a-c are solids stable enough to moisture and oxidation by molecular oxygen that they could be to be handled under air.
12
Typical Procedure for the Coupling Reaction: Aryl halide (1.0 equiv) and arylboronic acid (1.2 equiv) were added to a solution of KF (2.0 equiv), Pd(OAc)2 (1.0 mol%) and ligand (2.0 mol%) in toluene (0.5 M) at r.t. under a nitrogen atmosphere. The solution was stirred at 80 °C for 1-3 h. After cooling to r.t., the solution was diluted with toluene, washed with H2O and brine, dried over anhyd MgSO4 and concentrated under reduced pressure. The concentrate was purified by silica gel column chromatography to give the coupling products. 4-Methoxybiphenyl (Table 1, entry 1): 1H NMR (200 MHz, CDCl3): δ = 3.85 (s, 3 H), 7.04-6.93 (m, 2 H), 7.60-7.23 (m, 7 H). 13C NMR (50 MHz, CDCl3): δ = 55.3, 114.2, 126.6, 126.7, 128.1, 128.7, 133.8, 140.8, 159.1.