Boron tribromide → (S)-5-amino-2'-bromo-4'-fluoro-2,6-dihydrospiro[[1,4]oxazine-3,9'-xanthen]-7'-ol

Participants

Reaction Conditions

Reaction Steps

In a 500-mL flask, the (S)-2′-bromo-4′-fluoro-7′-methoxy-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-5-amine (0.676 g, 1.719 mmol) was suspended in dcm (50 mL). The suspension was cooled to 0° C., and a DCM solution of tribromoborane (1.0 M, 5.16 mL, 5.16 mmol) was added. After 1.5 h, the reaction was quenched with 9:1 aqueous NH4Cl/NH4OH (20 mL). The aqueous phase was extracted with 5% MeOH/DCM (3×50 mL). The organics were combined, washed with brine (15 mL), dried over sodium sulfate and concentrated to afford crude (S)-5-amino-2′-bromo-4′-fluoro-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-7′-ol (604 mg, 1.593 mmol) which was used directly in the next step.

Provenance & Evidence