Biphenyl is two benzene rings joined by a single bond. The site of substitution for a biphenyl is determined by (1) which phenyl ring is more activated (or less deactivated), and (2) which position on that ring is most reactive, using the fact that a phenyl substituent is activating and ortho, para-directing.
(a) Use resonance forms of a sigma complex to show why a phenyl substituent should be
ortho, para-directing.
(b) Predict the mononitration products of the following compounds.
(i)

(ii)

(iii)

(iv)

(v)

(vi)

Transcribed Image Text:

biphenyl OH -C-CH, NO2