Pinacol → 2-(Chloromethyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

To the mixture of triisopropyl borate (15 ml, 65 mmol), chloroiodomethane (13 g, 72 mmol), and tetrahydrofuran (78 ml), n-butyllithium (a 1.6 M n-hexane solution, 41 ml, 65 mmol) was added dropwise at −78° C. (an outer temperature) over 20 minutes, and then the obtained mixture was stirred at room temperature for 2.5 hours. The reaction mixture was cooled to 0° C. (an outer temperature), and a 4 N hydrochloric acid-ethyl acetate solution was added dropwise thereto at the same temperature until the reaction mixture became neutral. At the same temperature, pinacol (7.7 g, 65 mmol) was added to the reaction mixture, and then the reaction mixture was stirred at room temperature for 40 minutes. The solvents were evaporated under reduced pressure, and then the obtained residue was distilled under reduced pressure (63-70° C., 11 mmHg), thereby obtaining the entitled compound (9.2 g, 52 mmol, 81%).

1. additionwas added dropwise at −78° C. (an outer temperature) over 20 minutes
2. additionwas added dropwise
3. stirringthe reaction mixture was stirred at room temperature for 40 minutes
4. customThe solvents were evaporated under reduced pressure
5. distillationthe obtained residue was distilled under reduced pressure (63-70° C., 11 mmHg)

ORD record

ord-61095631ca8f4d5986f391df5efc7432

Source dataset

uspto-grants-2012_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08273885B2