N-Chloro and N-bromosaccharins: valuable reagents for halogenation of electron rich aromatics and cohalogenation of alkenes

N-Chloro- and N-bromosaccharins react with electron rich aromatic compounds (anisole, acetanilide, N,N-dimethylaniline) producing halogenated compounds. The reaction with N-bromosaccharin gives para- substituted compounds only, whereas N-chlorosaccharin produces orto and para mixtures (para isomer predominantly, ca. 4-5 : 1). The reactions of the N-halosaccharins with alkenes (cyclohexene, styrene, a-methylstyrene, and 1-hexene) give the corresponding halohydrins