CHEM 346 PROBLEM SET 2 ANSWER KEY 1 Ch 16 13 Each system look at which ring is more activated O O Br2 FeBr3 Br O O O O moderately deactivated moderately activated O Br2 FeBr3 H3C one weakly activating group one moderately deactivating group OCH3 O two moderately deactivating groups Br2 FeBr3 O weakly activated strongly activated NO2 Br2 FeBr3 H3CO one strongly activating group one weakly activating group aromatic ring one strongly deactivating group one weakly activating group aromatic ring H3CO Br Br O Br Br O Br NO2 H3C Br O OCH3 O O Br Br O Br O Br Br Br a b c d Ch 16 17 a O Cl CH3 AlCl3 O Cl AlCl3 CH3 O HNO3 CH3 H2SO4 meta directing group O CH3 H2SO4 CH3 O O CH3 NO2 meta directing group SO3H CH3Cl AlCl3 CH3 KMnO4 O HNO3 OH H2SO4 meta directing group O OH NO2 Ch 16 20 a Cl2 FeCl3 HNO3 H2SO4 Cl AlCl3 CH3Cl AlCl3 CH3Cl AlCl3 O Cl AlCl3 Cl NO2 HNO3 H2SO4 Cl2 FeCl3 NBS ROOR Cl Cl Sn HCl NO2 NO2 NH2 NH2 Sn HCl Cl Cl Br KOtBu CH3 KMnO4 CO2H CH3 HNO3 H2SO4 CH3 NO2 O Br2 FeBr3 HNO3 H2SO4 KMnO4 O Br CO2H NO2 CO2H NO2 H2NNH2 HO Br b c b d e f g Ch 16 45 Ch 16 51 a h i b c d e f O Cl AlCl3 Cl AlCl3 O H2NNH2 HO 1 Hg OAc 2 H2O 2 NaBH4 OCH3 vs SCH3 Br2 FeBr3 OH Br Anisole is fast at nitration because OMe is a strongly activating group due to the lone pair on oxygen having the ability to donate into the ring Thioanisole has a sulfur atom instead The electrons of the lone pair that will donate into the ring are in the 3p orbital which has worse overlap than the oxygen lone pair in the 2p orbital O CH3 good overlap S CH3 worse overlap OCH3 Cl NO2 anisole ethylbenzene benzene chlorobenzene nitrobenzene OH CH3 NO2 Cl NO2 O2N NO2 O2N O2N 2 4 dinitrophenol 2 4 dinitrotoluene 1 chloro 2 4 dinitrobenzene CH3 H3C HO CH3 CH3 p cresol p xylene toluene benzene CO2H phenol propylbenzene benzene benzoic acid H3C p chlorotoluene O2N p nitrotoluene 2 chloro 4 nitrotoluene CH3 O2N CH3 Cl CH3 O2N NO2 2 4 dinitrotoluene I Cl Br fluorobenzene chlorobenzene bromobenzene iodobenzene OH Cl F Ch 16 60 CH3 vs CH3 m xylene both meta not reactive site CH3 H3C p xylene one ortho one para CH3 Methyl group is an ortho para director m xylene is more reactive because both activating groups will be acting in concert H3C both ortho one ortho matched one meta not matched all other sites the same CH3 Br Cl Br O Cl O NO2 O2N O Br CH3 Cl HNO3 H2SO4 CH3 O2N Cl very little due to steric crowding CH3 Cl NO2 OCH3 NO2 BF4 NO2 BF4 OCH3 NO2 NO2 NO2 BF4 O N O F F F B F NO2 very little due to steric crowding H NO2 Br2 AlBr3 NO2 Br NO2 OH NO2 OH one ortho one para CH3 O Cl AlCl3 HNO3 H2SO4 Br Cl O Br2 FeBr3 Cl AlCl3 2 A B C D E F G 3 HO H O H H Site 3 is the least likely to be brominated The other sites can all be brominated by being influenced by strongly activating groups Site 1 1 2 N 3a 4a OCH3 3 4 Site 2 Br Br 3 3a 4 4a Br Br Site 4 R H Br N R N R Br H R Br Br OCH3 OCH3 Br H 4 A B HO O Cl AlCl3 O Cl2 FeCl3 OH H2SO4 O H2SO4 Br O Cl2 FeCl3 SO3H O Cl Br H2O SO3H H2NNH2 HO Cl Br2 FeBr3 SO3H Br O Cl N R N R O Cl O