Natural products often incorporate chlorine or bromine, but less rarely are both halogens found in the same molecule. When they are, the problem becomes how to distinguish them. Typically, chlorinated carbon resonances are assumed to be shifted further downfield than brominated ones. This rule of thumb was of no help to one of our users who recently isolated a compound containing both chlorine and bromine because the two halogenated carbons had very similar chemical shifts. How then could we distinguish the two halogens?
