what do activating groups do?
increase the reactivity of the benzene ring
what will happen to the reaction if the compound has an activating group?
reactions will be faster
need lower temps
need more mild conditions
what do deactivating groups do?
decrease the reactivity of the benzene ring
what will happen to the reaction if the compound has a deactivating group?
reactions will be slower
need higher temps
need harsher conditions
what are positions 2/6 known as?
ortho
what are positions 3/5 known as?
meta
what is position 4 known as?
para
what are ortho/para directing groups?
NH2 NHR
force an additional group to substitute onto the ortho or para position on the benzene ring
all activating groups
donate electrons onto the ring
reactivity increases
2nd substitution will be on ortho/ para position
name a meta directing group
NO2
what do meta directing groups?
they force an additional group to substitute onto the meta position on the benzene ring
groups withdraw electrons from ring
reactivity decreases
2nd substitution at meta position
what are electron-donating groups?
electrons in orbitals that overlap with the delocalised ring and increase its electron density
examples of electron-donating groups
OH and NH2
where do electron-donating groups direct substitutions to?
2,4 and 6
what are electron withdrawing groups?
doesn’t have any orbitals that overlap with the delocalised ring and it’s electronegative so it withdraws electron density from the ring
examples of electron withdrawing groups
NO2
where do electron withdrawing groups direct substitutions to?
3 and 5