Water → 4-Benzyloxy-phenylboronic acid

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Reaction Steps

143 ml of a solution of n-Butyllithium (nBuLi) is added dropwise, under inert gas and at -78° C., to 47.08 g of the product obtained in Stage A in 375 ml of tetrahydrofuran (THF), agitation is carried out for 1 hour, then 36.5 ml of triethylborate is added. Agitation is carried out for 14 hours, while leaving the temperature to rise to 20° C., and the reaction medium is hydrolyzed using a solution of ice-cooled water containing 45 ml of concentrated sulphuric acid, for 1 hour at 20° C. The aqueous phase is extracted with ethyl acetate, the organic phases are washed with 2N soda and the aqueous phase is acidified to pH=1 using a 1N solution of hydrochloric acid in order to precipitate the boronic acid. After filtration and drying the precipitate 28.54 g of expected product is obtained. Rf: 0.16 cyclohexane/ethyl acetate 7/3) I.R. spectrum: (Nujol)

Provenance & Evidence