Trifluoroacetic acid → (2S)-2-[2-borono-4-(trifluoromethyl)phenoxy]-propanoic acid

Participants

Reaction Steps

TFA (10 ml) was added to a solution of the product from step (iii) (4.0 g) in DCM (100 ml) and stirred for 30 min. The TPA was evaporated and the residue dissolved in a mixture of 1M hydrochloric acid (30 ml) and acetonitrile (30 ml) After 1 h the mixture was evaporated to dryness, dissolved in 1M sodium hydroxide, washed with ether and adjusted to pH 2 with concentrated hydrochloric acid. The aqueous was then extracted with ether, washed with brine, dried (MgSO4) and evaporated. Yield 2.0 g. The crude material was carried forward to step (v).

Provenance & Evidence