Hydrochloric Acid → (4-{[tert-Butyl(diphenyl)silyl]oxy}-3-methoxyphenyl)boronic acid

Participants

Reaction Steps

At −78° C., 140 ml n-BuLi (1.6 M in hexane, 223.8 mmol) in 600 ml THF are added to a solution of 89.92 g (203.4 mmol) (4-bromo-2-methoxy-phenoxy)-tert-butyl-diphenyl-silane over a period of 30 minutes. After further 30 minutes at −78° C., 140.9 ml (610.4 mmol) triisopropylborate are added over a period of 30 minutes. The mixture is allowed to warm up to room temperature and is then hydrolysed at 0° C. with a 10% HCl solution within 30 minutes. After separation of the water phase, the organic phase is dried over MgSO4, condensed and the residue is crystallized-from ethyl acetate and a mixture of ethyl acetate/heptane, yielding. 4-(tert-butyl-diphenyl-silanyloxy)-3-methoxy-phenyl-boronic acid is isolated as a light yellow solid (m.p. 193–196° C.).

Provenance & Evidence