Figure 49.
(A) NBS-mediated selective bromination of HA of 313. (B) NBS-mediated bromination of HA and the alkene of 314. The incipient brominum intermediate undergoes EAS. (C) Substrate and reagent controlled bromination. While most brominating sources functionalize HA, treatment of 317 with BDSB results in bromination of HB. (D) Brominating agents.248 Abrev. NBS: N-bromosuccinimide; NBSac: N-bromosaccharin; TBCO: tetrabromocyclohexadienone; NBA: N-bromoacetamide; TCCA: trichlorocyanuric acid; BDSB: Bromodiethylsulphide bromopentachloroantimonate.