CHE3703 - Organic Chemistry III

CHE3703
Organic
Chemistry III

, CHE3703/201/2/2019




Tutorial Letter 201/2/2019

Organic Chemistry (III)
CHE3703

Semesters 2


Department of Chemistry


This tutorial letter contains assignment 02 keys.

, CHE3703/201/2/2019


QUESTION 1
1.1


H O Nu
H O H O H O
Nu



N O N O N O
O N O O O
O


The nitro group is strongly electron withdrawing by both inductive effect and resonance effect,
and it pulls electrons away from the ring making it electron poor and therefore electron
withdrawing. The ring, in turn, withdraws electrons from the carbonyl group making the
carbonyl carbon electron poor and therefore strongly electrophilic for attack by a nucleophile.



H O H O H O Nu
O
H
Nu


OCH3 OCH3 OCH3 OCH3




The methoxy group is moderately electron donating by inductive effect and strongly donating
by resonance effect. The methoxy group pushes the electron density towards the ring by
inductive effect operating through the sigma bond making it electron rich. Oxygen of the
methoxy group donates a pair of electrons towards the ring by resonance effect operating
through pi bonds and become positively charged. The ring becomes electron rich with one of
the resonance hybrids having adjacent opposite charges. This resonance hybrid is neutral and
therefore poorly electrophilic.
(8)




2