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Zn(Hg)

Problem. Review from Monday. C. H. 3. C. H. C. H. 3. 3. C. H. C. l. C. H. 3. 3. A. l. C. l. 3. O. C. H. 3. Multiple Additions may be a problem You may get lots of ortho to throw away. C. l. A. l. C. l. 3. Problem. C. H. 3.

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Zn(Hg)

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  1. Problem Review from Monday C H 3 C H C H 3 3 C H C l C H 3 3 A l C l 3 O C H 3 Multiple Additions may be a problem You may get lots of ortho to throw away C l A l C l 3 Problem C H 3 C H C H O 3 3 H H Zn(Hg) + H H Would it help to change the order? HCl O

  2. O O O O C H C H C l 3 C l 3 + A l C l 3 A l C l 3 C H 3 Deactivating group. No Friedel Crafts Z n ( H g ) H C l C H C l 3 A l C l 3 O Z n ( H g ) C H H C l 3 C H 3 C H 3

  3. O O H C l O O A l C l 3 Predict the main product O O O O O O A B C D E F O O O O O O

  4. O O H C l O O A l C l 3 O H O O O

  5. O O H C l O O A l C l 3 Predict the main product O O O O O O A B C D E F O O O O O O

  6. H + H - F F Draw a mechanism and predict the product F F A B C D E F G F F

  7. Review from Monday Electrophilic Aromatic Substitution Reactions C H C H C H C H 3 3 B r 3 3 B r B r - B r B r H B r / F e B r 2 3 + + + B r - F e B r 3 B r B r F e B r 3 60% 39% <1%

  8. Review from Monday C H C H C H 3 3 3 B r B r B r H H H C H C H C H C H 3 3 3 3 B r B r / F e B r Methyl does not help meta 2 3 + + Methyl helps stabilize ortho H B r C H 2 B r B r H (and para) para 60% 39% <1%

  9. Electron Donating Groups d- d- Most basic sites d- C H 3 Electron Withdrawing Groups d+ d+ Most basic sites d+

  10. para ortho d- d- O C H d+ 3 d+ O C H C Bad 3 C B r / F e B r 2 3 slower B r m a i n p r o d u c t Avoids putting d+ near d- d+ Meta wins

  11. Electrophilic Aromatic Substitution Reactions B r B r B r - B r / H + B r - F e B r 3 Two more C l - C l / A l C l 3 F e B r 3 C l N O S O H 2 3 O C H - C l / A l C l 3 3 C H C l 3 A l C l 3 C H 3 O Friedel Crafts Alkylation C C H 3 Friedel Crafts Acylation

  12. O O N O O / H S O H N O H N O 2 4 3 no reaction N - H O Electrophilic Aromatic Subsitution How can you make HNO3 a stronger acid? Add another acid. O H N O O O O O O N H H N S H S O O O O O O O O O N i t r o n i u m i o n H H

  13. O O S O H 3 O Fuming S H S O H 2 4 no reaction O S O O Electrophilic Aromatic Subsitution How can you make H2SO4 a stronger acid? Add another acid. O O O + - H O + H S O + H S S H S 3 4 O O O O O O O H O H

  14. Now that we have all our reactions, lets summarize activation and deactivation Electron Donating Groups activate the ring Best O H C C H 3 3 C H N H N H N 3 2 Which one is not a EDG? A B C D C H O 3 H H C O O 3 O O H C O 3 Direct substitution ortho/para E F G H

  15. Now that we have all our reactions, lets summarize activation and deactivation Electron Withdrawing Groups deactivate the ring Best H N O O O O N H N H 3 2 C S O H N 3 + H anilinium aniline C H C H 3 3 H O R O O O H N O • EDG or • EWG ? Direct substitution meta

  16. O O O H O O O O O H O p k = 9 . 9 9 a O H N N O O O O O O H C H C 3 3 p k = 7 . 1 5 p k = 1 0 . 2 1 a a Predict pKa N O O A. less than 10 B. greater than 10

  17. -X pKa -H -NO2 -OCH3 -CH3 -CN -COCH3 -CF3 -F -Cl 9.99 7.15 10.21 X X O H O 10.26 8.61 8.05 d- 8.68 inductive effect resonance effect 9.89 9.41

  18. C l What about a halide? Does a Cl activate or deactivate the ring? d- C l C l C l C l d+ inductive effect resonance effect Cl poor at p bonding Deactivates,but directs ortho-para

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