Hydrochloric Acid → 2-Benzyloxy-5-chlorobenzeneboronic acid

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Reaction Steps

A solution of butyl lithium (1.6M in hexane) (50 ml) was added dropwise to a stirred solution of the product from step (i) (23 g) in diethylether (300 ml) at −70° C. After 1 h a further 18 ml of butyl lithium was added, left for 0.75 h, then trimethylborate (10 ml) added and the mixture warmed to RT and left for 16 h. 2M Hydrochloric acid (100 ml) was added, stirred for 1 h then the organic layer separated and extracted with aqueous sodium hydroxide solution. The basic layer was acidified with 2M hydrochloric acid solution, extracted with diethylether which was dried and evaporated under reduced pressure. The residue was triturated with iso-hexane and filtered. Yield 10.8 g

Provenance & Evidence