0环行 Allylic Halogenation 摆院 allylic positions allylic hydrogens HH H Br Br2 hv HBr cyclohexene HH 3-bromocyclohexene (80%) Copyright 2010 Pearson Prentice Hall,Inc. Allylic radical is resonance stabilized. Bromination occurs with good yield at the allylic position (sp3 C next to C=C). Allylic Halogenation Allylic radical is resonance stabilized. Bromination occurs with good yield at the allylic position (sp3 C next to C=C)