Reactions of Aromatic Compounds Answer Key

Practice Problems for Chapter 17: Reactions of Aromatic Compounds 1) Provide the major resonance structures of the intermediate sigma complex in the reaction of benzene with the generic electrophile E+. 3) Under what reaction conditions does the electrophilic chlorination of aromatic compounds usually occur? A) Cl2, AlCl3 B) Cl2, H2O C) Cl2, CCl4 D) NaCl, H2O E) NaCl, CH3OH 4) In the bromination of benzene using Br2 and FeBr3, is the intermediate carbocation aromatic? Explain. 5) In electrophilic aromatic substitution reactions a bromine substituent: A) is a deactivator and a m-director. B) is a deactivator and an o,p-director. C) is an activator and a m-director. D) is an activator and an o,p-director. E) none of the above 6) Which of the following is the best choice of reagents to effect the electrophilic iodination of an aromatic ring? A) KI, acetone B) I2, CH3CN C) KI, HNO3 D) I2, HNO3 E) none of the above 1 9) Provide a detailed, stepwise mechanism for the reaction of benzene with Br2 and FeBr3. Make sure to include the activating reaction between Br2 and FeBr3 in your mechanism. 10) Which of the following species is attacked by benzene in the electrophilic nitration reaction? A) HNO3 B) NO2+ C) NO2 D) NO+ E) N312) Provide the necessary reagents to accomplish the following transformation. 13) Which of the following is the strongest activating group in electrophilic aromatic substitution reactions? A) -CH2CH3 B) -OCH3 C) -CO2CH3 D) -NO2 E) -N(CH3)2 2 14) Provide the structure of the major organic product(s) in the following reaction. 16) In electrophilic aromatic substitution reactions, a -NHCOCH3 substituent on the aromatic ring is: A) a deactivator and a m-director. B) a deactivator and an o,p-director. C) an activator and a m-director. D) an activator and an o,p-director. E) none of the above. 17) Which of the following compounds will undergo Friedel-Crafts alkylation with (CH3)3CCl, AlCl3 most rapidly? A) toluene B) iodobenzene C) acetophenone D) benzenesulfonic acid E) cyanobenzene 18) Which of the following compounds will react most rapidly when treated with CH3CH2Cl and AlCl3? A) benzene B) chlorobenzene C) nitrobenzene D) anisole E) toluene 19) Which sequence correctly ranks the following aromatic rings in order of increasing rate of reactivity with chlorine and aluminum chloride? A) 1 < 2 < 3 B) 2 < 3 < 1 C) 3 < 2 < 1 D) 2 < 1 < 3 E) 1 < 3 < 2 3 23) Which of the following is an intermediate in the bromination of toluene? A) B) C) D) 26) Draw the four major resonance structures of the sigma complex intermediate in the reaction of anisole with HNO3/H2SO4 to yield p-nitroanisole. 27) Provide the structure of the major organic product(s) in the following reaction. 34) Which of the following compounds will react least rapidly when treated with CH3CH2Cl and AlCl3? A) o-xylene B) acetanilide C) toluene D) benzene E) bromobenzene 4 36) Provide the major organic product of the following reaction. 37) Provide the major organic product of the following reaction. 38) Provide the structure of the major mononitration product of the compound below. 41) Provide the structure of the major organic product(s) in the following reaction. 42) Which of the following compounds undergoes reaction with HNO3/H2SO4 at the fastest rate? A) ethylbenzene B) benzenesulfonic acid C) nitrobenzene D) chlorobenzene E) acetophenone 5 44) Provide the major organic product(s) of the reaction shown below. 46) Provide the major organic product(s) of the reaction shown below. 49) Rank the following sigma complexes in order of increasing stability. 50) Provide the major organic product(s) of the reaction shown below. 6 52) Provide the major organic product of the following reaction. 54) Provide the major organic product of the following reaction. 57) Provide the major organic product of the following reaction. 7 63) Provide the major organic product(s) of the reaction shown below. 66) Provide the structure of the major mononitration product of the compound below. 71) Provide a series of synthetic steps by which the compound below can be prepared from benzene. 74) Provide the structure of the major organic product of the following reaction. 77) Provide a detailed, stepwise mechanism for the following reactions. 8 78) Predict the two major products from the following reaction. (Mark all correct responses.) A) B) C) D) E) 79) Which of the following reactions will actually yield the indicated product? A) B) C) D) 9 E) 83) Show what reagents are needed to complete the transformation below. 86) Provide the structure of the major organic product of the following reaction. 87) Provide the major organic product of the following reaction. 89) Provide the major organic product of the following reaction sequence. Answer: 10 91) Complete the following reaction by filling in the necessary reagents. 93) Show how the following product can be made from benzene. 97) Provide the structures of the major organic products of the following reaction. 98) Provide the major organic product(s) of the reaction shown below. 11 100) Provide the structures of the major organic products of the following reaction. 104) Which of the following is an intermediate when 1,2-dibromo-4-nitrobenzene is heated with NaOH in a nucleophilic aromatic substitution reaction? A) B) C) D) 105) Provide a detailed, stepwise mechanism for the following reaction. 12 107) Provide a series of synthetic steps by which p-nitrophenol can be prepared from benzene. 110) Provide the structures of the major organic products in the following reaction. 112) Draw a correct structure for the reaction below. 113) Provide the structure of the major organic product in the following reaction. 114) Provide the structure of the major organic product in the following reaction. 13 115) Provide the structure of the major organic product in the following reaction sequence. 117) Provide the structure of the major organic product in the following reaction. 119) Predict the major product from the following reaction: A) B) C) D) E) 14 127) Provide the structure of the major organic product in the following reaction. 128) Complete the following reaction by filling in the necessary reagents. 129) Provide the structure of the major organic product in the following reaction. 15