General procedure for the synthesis of 4,4,5,5-tetramethyl-2-(2-(naphthalen-2-yl)phenyl)-1,3,2-dioxaborolane (E5) from 2-(2-bromophenyl)naphthalene (E3) and pinacolborane (E4): To a 200 mL three-necked flask were added 2.60 g (9.18 mmol) of 2-(2-bromophenyl)naphthalene (E3), 3.53 g ( 27.5 mmol) of pinacolborane (E4), 2.79 mg (27.5 mmol) of triethylamine and 498 mg of Ni(dppp)Cl2 catalyst, followed by the addition of 30 mL of toluene as a solvent. The reaction mixture was heated to 95 °C and stirred for 5 h under nitrogen protection. Upon completion of the reaction, water and toluene were added to the reaction mixture for extraction, and the organic layer was separated and dried over anhydrous sodium sulfate. The organic solvent was removed by distillation under reduced pressure and the resulting crude product was purified by silica gel column chromatography (eluent: toluene/heptane=1:1, v/v) to afford 1.70 g (yield: 56%) of the target product 4,4,5,5-tetramethyl-2-(2-(naphthalen-2-yl)phenyl)-1,3,2-dioxaborolane (E5) as a white solid.
