CHEM 210 Lecture Notes - Lecture 29: Benzene, Lone Pair, Substituent
Document Summary
Once a benzene ring has a substituent, different regions are defined (i. e. regiochemistry!) Meta- two identical positions adjacent to the ortho positions. Para - a unique position, next to the meta positions and across from the carbon with the s. S = some group that has already been placed on the ring. Ortho - two identical positions adjacent to the carbon with s. S ortho para positions meta positions, and the carbon with the s. D = atom with lone pair or r, a typical (non inductive) alkyl group. Generally these are considered activating on the ring, tending to increase the ring"s reactivity (exception is halogens, which slightly deactivate). A a donating group - donating electron density into the ring. The next e+ will be attracted to these negative sites.
