Organohalide

An organic compound with a carbon–halogen bond. Alkyl, allylic and vinylic attachment differ in geometry and substitution reactivity.

An organohalide with the halogen attached directly to an aromatic ring carbon. Its substitution chemistry differs from an alkyl halide because the C–halogen bond is attached to an sp2 carbon.

${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{Br}$, an aryl bromide that can be converted to an aryl grignard reagent. Bromine directs electrophilic aromatic substitution preferentially to the ortho and para positions while deactivating the ring overall.

${\mathrm{C}}_6{\mathrm{H}}_{11}\mathrm{Br}$. magnesium insertion provides a cyclohexyl organometallic reagent, while base-induced elimination provides cyclohexene.