“…Representative procedure: Synthesis of 18: n-Butyllithium in hexane (2.2 mmol, 0.91 mL of a 2.42 m solution in hexane) was added dropwise under argon to a solution of 1,1-dibromocyclopropane (5) [15] (440 mg, 2.2 mmol) in anhydrous THF (20 mL) at À110 8C, and the mixture was stirred at À110 8C for 5 min. The mixture was then treated with trimethylene cyclopropaneboronate (14) (252 mg, 2.0 mmol), and the resulting mixture was gradually warmed to room temperature within approximately 12 h. After that, dibromide 5 (440 mg, 2.2 mmol) was added at 25 8C, and the mixture was cooled to À110 8C again.…”