Bromination of benzo[e]-1,2-oxaphosphorinine derivatives

Using NMR spectroscopy, we found that the reactions of 6-chloro-2-hydroxy-2-oxo-4-phenyl- and 2,6-dichloro-2-oxo-4-phenylbenzo[e]-1,2-oxaphosphorinines with molecular bromine result in 3-bromo-6-chloro-2-hydroxy-2-oxo-4-phenyl- and 3-bromo-2,6-dichloro-2-oxo-4-phenylbenzo[e]-1,2-oxaphosphorinines in high yields.