Examination%20_1%20Spr%202008

Formation of this intermediate is disfavored the

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Unformatted text preview: N MINOR δ+ δ+ δ+ C N Cl H N Cl ortho-substitution intermediate is destabilized due to the proximity of partial carbocation charge to the electron withdrawing group. A resonance contributor with a repulsive interaction between adjacent carbon atoms exists. Formation of this intermediate is disfavored. The intermediate for para-substitution is similarly destabilized. MINOR δ+ δ+ C Cl H MAJOR Cl H Cl3Fe Cl δ+ δ+ δ+ N C δ+ The intermediate for meta-substitution is not destabilized in this manner, and is therefore the most readily formed. The m-isomer is the dominant product Cl CN + HCl + FeCl3 Question 6 (12 points). Predict, with reference to the relevant reaction mechanism, the outcome of the following reaction (including stereo‐ and regiochemical outcomes). You must include the detailed reaction mechanism in your answer, and may include other structures or diagrams to explain your answer. OCH3 HNO3/H2SO4 ∆ H HNO3 + H2SO4 O ON H O + HSO4 δ+ δ+ O -OCH3 is resonance electron donating. It is a ring activating group that directs ortho- and para-. ONO + H2 O OCH3 MAJOR δ+ CH3 Positive charge may be delocalized onto O, due to resonance electron donationg character of -OCH3 group. The additional delocalization leads to stabilization of the ortho-intermediate; the orthoproductis favored. OCH3 NO2 OCH3 +H O2N δ+ NO2 H ONO MAJOR δ+ δ+ +H O δ+ CH3 H O2 N MINOR δ+ The para-intermediate is stabilized in a similar manner by the -OCH3 group, and so...
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