Hydrogens on these molecular features can be targeted by nitroalkanes via the vicarious release of a besyl (“beh-sill”) group. Arrows drawn across these features indicate valid sites for “migration” using a rule developed by Erich Clar. Alkyl groups on these features can be rearranged by heating over a zeolite to adjust the ratio of BTX compounds. Amines on these features are replaced by in situ transformation into a salt with nitrous acid, followed by cleavage in the presence of copper. Nucleophiles perform a frontside attack at the ipso position of these structures, forming an intermediate whose charge is delocalized over five carbons. Adding a directing group to these structures can constrain later substitutions to the o- and p- positions. For 10 points, what structures are targeted for electrophilic substitution in a Friedel–Crafts reaction? ■END■
ANSWER: arenes [or aromatic rings; accept benzene rings, benzenoids, aryl groups, or phenyl groups; accept polycyclic aromatic hydrocarbons; prompt on rings, cycles, cyclic compounds, or conjugated compounds]
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= Average correct buzz position