Triisopropyl borate → 2-((4-(2-Methoxyethoxy)phenoxy)methyl)-4-chlorophenylboronic acid

Participants

Reaction Conditions

Reaction Steps

In a flask, 1.8 g (4.8 mmol) of the compound obtained in Step 2 was dissolved in 10 ml of anhydrous THF, and 1.34 ml (5.8 mmol) of triisopropyl borate was added thereto. The flask was cooled to −78° C. over a dry ice-acetone bath, 2.3 ml (5.8 mmol) of 2.5 M n-BuLi (in hexane) was added dropwise to the mixture over 15 min. After the reaction mixture was kept for 1 hour, the dry ice-acetone bath was removed, and 5 ml of 2 N HCl was added to the mixture. After stirring the mixture for 1 hour, the water layer was separated and extracted twice with 10 ml portions of ethyl acetate. The organic layers were combined, washed with a brine solution, dried over anhydrous MgSO4, and filtered under a reduced pressure to remove the solvent. The residue was recrystallized from ethyl acetate/hexane to obtain 1.12 g (yield 69%) of 2-((4-(2-methoxyethoxy)phenoxy)methyl)-4-chlorophenylboronic acid.

Provenance & Evidence