The general procedure for the synthesis of iodomethylboronic acid pinacol ester from bromomethylboronic acid pinacol ester is as follows:[Example 22] Synthesis of 2-(iodomethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane. 2-(Bromomethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.0 g, 8.3 mmol) was mixed with acetone (17 ml), sodium iodide (1.9 g, 13 mmol) was added, and the reaction mixture was stirred for 2 hours at room temperature. After completion of the reaction, the insoluble impurities were removed by filtration and the filtrate was concentrated under reduced pressure to remove the solvent. Hexane was added to the residue and filtered to remove insoluble matter. Finally, the solvent was evaporated under reduced pressure to afford the target product pinacol ester of iodomethylboronic acid (2.2 g, 97% yield). The product was characterized by 1H-NMR (CDCl3): δ 1.29 (12H, s), 2.59 (2H, s).
