Br[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1.II.[Mg].Cl[P:18]([C:23]([CH3:26])([CH3:25])[CH3:24])[C:19]([CH3:22])([CH3:21])[CH3:20]>C1COCC1>[C:19]([P:18]([C:23]([CH3:26])([CH3:25])[CH3:24])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)([CH3:22])([CH3:21])[CH3:20]A solution of 2-bromobiphenyl (5.38 g, 23.1 mmol) and a few iodine crystals in 40 mL of THF with magnesium turnings (617 mg, 25.4 mmol) was heated to a reflux for 2 h. Heat was temporarily removed for the addition of cuprous chloride (2.40 g, 24.2 mmol) followed by chlorodi-tert-butylphosphine. Heating was resumed for 8 h. The reaction mixture was then removed from heat and allowed to cool to rt. The reaction mixture was poured onto 200 mL of 1:1 hexane/ether. The suspension was filtered and the filtercake was washed with 60 mL of hexane. The solid was partitioned between 150 mL of 1:1 hexane/ethyl acetate and 60 mL of concentrated ammonium hydroxide with 100 mL of water. The organic layer was washed with 100 mL of brine, dried over anhydrous sodium sulfate, and concentrated in vacuo. The white solid was recrystallized from 30 mL of MeOH to give white crystals of 2-(di-tert-butylphosphino)biphenyl (4.01 g, 58%). A second crop (464 mg, 67%) was obtained by recrystallization from 50 mL of MeOH and 25 mL of water.
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