Directing groups

What are directing groups? Substitution of a 2nd group on a benzene ring The 1st group directs the position of the 2nd substituted group Two types 2‐ and 4‐directing groups activate the ring: reactivity increases 3‐directing groups deactivate the ring: reactivity decreases

2- and 4- directing groups 1 2 3 4 6 5 2- and 4- directing groups: –OH, NH2 Group donates electrons onto ring Reactivity increases 2nd substitution at 2- or 4- positions 1 2 3 4 6 5 4 +

3- directing groups 1 2 3 4 6 5 3- directing groups: –NO2 Group withdraws electrons from ring Reactivity decreases 2nd substitution at 3- position 1 2 3 4 6 5