Hydrochloric Acid → 4-(tert-Butyldimethylsilyloxy)phenylboronic Acid (contains varying amounts of Anhydride)

Magnesium turnings (0.53 g, 22 mmol) and 20 mL of THF were placed into a two-necked flask. Next, tert-butyldimethylsilyloxyphenyl bromide (5.64 g, 19.6 mmol) was added and the mixture was heated under reflux for 2 h before it was cooled to room temperature. The brown mixture was added to a solution of trimethyl borate (2.43 g, 24 mmol) in 5 mL of THF through a dropping funnel at −78° C. and allowed to warm to room temperature overnight. After hydrolysis with 90 mL of ca. 0.1 M hydrochloric acid followed by standard work-up with methyl tert-butyl ether, the brown residue was washed with 20 mL of cold hexane, and the resulting white product (3.86 g, 78%) was dried in vacuo. Mp: 175° C. (1H NMR (300 MHZ, CDCl3): δ0.25 (s, 6H); 1.01 (s, 9H); 6.95 (d, J=8.5 Hz, 2H); 8.11 (d, J 8.5 Hz, 2H). 13C NMR (75 MHZ, CDCl3): δ−4.3; 18.1; 25.7; 119.8; 137.5; 159.8. Reference: Bolm, C.; Derrien, N.; Seger, A. Synlett 1996, 387.

1. temperaturethe mixture was heated
2. temperatureunder reflux for 2 h before it
3. temperatureto warm to room temperature overnight
4. washthe brown residue was washed with 20 mL of cold hexane
5. dry with materialthe resulting white product (3.86 g, 78%) was dried in vacuo

ORD record

ord-3fda65830b73464d8c7af15cf220e52b

Source dataset

uspto-grants-2002_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06403522B1