CHEM 2312 Midterm: CHEM 2312 GT Examp2ii

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turquoisegnu128

15 Feb 2019

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E2 practice ii: (32 points) circle the letter on the right which corresponds to the answer to each question. Cn i ii iii iv (iv) which of the following sets of substituents are all electron withdrawing substituents, thereby decreasing the rate of electrophilic aromatic substitution reactions: ch3, -cl, -och3 n. -no2, -cf3, -nhcoch3 o. Aa. departure of cl-, followed by nucleophilic addition. Bb. nucleophilic addition followed by leaving group departure (viii) which of the following is the active electrophile in friedel-crafts acylation of benzene in the presence of 2-methylpropanoyl chloride, (ch3)2chcocl, with alcl3? (ch3)2ch (ch3)2ch-c. Ff: (38 points) (a) provide the structure of the major organic products of the following reactions. Provide a sequence of reactions to perform each transformation, showing the reagents and structures of all isolated synthetic intermediates. The synthesis must use the given starting materials; you may also use any other starting materials with 3 or fewer carbon atoms.

Related Questions

1. Of Huckel's requirements for aromaticity, only this one is NOT required in the case of some compounds to be considered aromatic? 8. Which sequence of reagents would produce b) The system must be monocyclic. c) There must be (4n + 2) Ï electrons. d) The Huckel number of electrons must be completely 2. Zn(Hg), conc. HC delocalized. 2. 4-amino-2-chlorobenzaldehyde is NOz H2N NO2 3. Which of the following compounds are aromatic? Hint: 9. Refer to the following list of possible answers: So ) halogen h) RC-O D diazonium ion a. What group weakly activates benzene to b. What group slightly deactivates benzene to SeAr because a) I and II only c)I, II and â ¢ b) II and III only d) I and IlI only SAr by a +I e-donor inductive effect? of its-I withdrawal inductive effect, but is an ortho-/para- director because of its +R resonance e-donor 4. Which one of the following compounds is anti-aromatie? c. What group inhibits Friedel-Crafts alkylation and acylation d. What species is the electrophile e. What species is formed when but strongly activates a halo benzene to S&Ar because of its strong -R e-withdrawal resonance effect? In which case is the indicated unshared pair of electrons Nora contributor to the Ï aromatic system? 5. in Friedel-Crafts acylation? aniline reacts with NaNO HCVS? 10. Arrange these benzene compounds in order of decreasing (fastest to slowest) SeAr reactivity: . Cyclopentadiene is unusually acidic for a hydrocarbon a) The carbon atoms are all sp hybridized. b) Cyclopentadiene is aromatic. c) Removal of a proton from cyclopentadiene yields an a) III > IV > 11 > 1 c) IV I> III d) IV > â ¡ > I> aromatic anion. d) Removal of a hydride ion from cyclopentadiene What might be predicted to happen when the following substance undergoes Friedel-Crafts acylation? produces an aromatic cation. 11. Recalling that benzene has a resonance energy of 152 k mol and naphthalene has a resonance energy of 255 k mol', predict the two positions which would be occupied by bromine when phenanthrene (below) undergoes addition of Brã (circle two numbers). a) Substitution occurs in ring A, o- to the methylene gro b) Substitution occurs in ring A, o-to the nitro group. c) Substitution occurs in ring A, m- to the methylene g d) Substitution occurs in ring B, o-/p- to the methylene e) Substitution occurs in ring B, m. to the methylene 10 9

Question V,Vi

1. Which of the following reagent(s) can be used to prepare a mixture of o and p-nitro toluene from toluene

(A) HNO₂ (B) HNO₃ (C) HNO₃/Fe (D) HNO₃/H₂SO₄ (E) NaNO₂

(A) H₂SO₃ (B) SO₃/ Which of the following reagent(s) can be used to convert nitrobenzene to m-nitrobenzenesulfonic acid Fe (C) H₂SO₃/Fe (D) H₂SO₄/Al₂(SO₄)₃ (E) H₂SO₄.SO₃

3. Which of the following reagent(s) can be used to prepare bromobenzene from benzene

(A) NBS (B) Br₂/FeBr₃ (C) H₂SO₄/Br₂ (D) Br₂/AlBr₃ (E) Br₂/Pd

4. Which of the following functional groups are o,p-directing ?

(A) Br, CH₂CH₃, NH₂ (B) Cl, NH₂, COOH (C) I, SO₃H, OH (D) OCH₃, Cl, COCH₃ (E) NO₂, CH₃, OH

5. Which of the following reagent(s) gives the reaction below

(A) CH₃Cl (B) Cl₂/ Fe (C) Cl₂/ AlCl₃ (D) Cl₂/ FeCl₃ (E) Cl₂/ HCl

6. Friedal-Craft acylation reagent(s)

(A) CH₃Cl/AlCl₃ (B) Cl₂/CH₃COCl (C) CH₃COCl/AlCl₃ (D) CH₃COCl/FeCl₃ (E) CH₃Cl/FeCl₃

7. Which of the following functional groups are m-directing ?

(A) NO₂, CH₃, OH (B) Br, NH₂, COOH (C) I, SO₃H, OH (D) OCH₃, Cl, COCH₃ (E) COCH_3, SO₃H, CHO

8. Which of the following compound can be used in the Diels-Alder reaction

(A) 2-methyl, 2,4-hexadiene (B) 2,5-hexadiene (C) 1-methyl,cyclohexa-1,4-diene (D) cyclohexa-1,4-diene

(E) 2-methyl, 1,5-hexadiene

9. Which statement about benzene is incorrect?

(A) The Cï¿½C p - bonding is delocalized (B) The C₆ ring is planar (C) The average C - C bond distance is the same as C-C double bonds (D) Each C atom is sp² hybridized ( E ) There are 12 s (sigma) bonds in benzene

10. Which of the following is NOT aromatic

(A) Cyclopropenyl cation (C₃H₃⁺) (B) Benzene (C₆H₆) (C) [16]-Annulene (C₁₆H₁₆)

(D) Cycloheptatrienyl cation (C₇H₇⁺) (E) [18]-Annulene (C₁₈H₁₈)

11. Conjugate addition of one equivalent of deuterium bromide (DBr) to 1,3-butadiene gives

(A) 3-bromo, 4-deutero, 1-butene (B) 3-bromo, 4-deutero, 2-butene (C) 4-bromo, 3-deutero, 1-butene (D) 1-bromo, 4-deutero, 2-butene (E) 1-bromo, 4-deutero, 1-butene

12. Which of the following is a conjugated diene

(A) cyclopentadiene (B) 2-methylcyclohexanone (C) 1-methyl,cyclohexa-1,4-diene (D) cyclohexa-1,4-diene

(E) cycloocta-1,5-diene

13. The aromatic compound is

14. Which of the following reaction involves a benzyne mechanism ?

(A) Ph-CH₃ ? Ph-COOH (B) Ph-CH₃ ? Ph-CHO (C) Ph-OH ? Ph-Cl (D) Ph-Cl ? Ph-OH

(E) none of these

15. Which of the following reagent(s) can be used to prepare a mixture of o and p-nitro toluene from

toluene

(A) HNO₂ (B) HNO₃ (C) HNO₃/Fe (D) HNO₃/H₂SO₄ (E) NaNO₂

16. Friedal-Craft alkyation reagent(s)

(A) C₂H₅Cl/AlCl₃ (B) Cl₂/CH₃COCl (C) CH₃COCl/AlCl₃ (D) CH₃COCl/FeCl₃ (E) CH₃Cl/FeCl₃

17. Which of the following functional groups are o,p-directing ?

(A) NO₂, SO₃H, CHO (B) Br, NH₂, COOH (C) I, OH, CH₃ (D) OCH₃, Cl, COCH₃ (E) COCH_3, SO₃H, Br

18. Major product in the reaction of benzene with 1-bromopropane, in the presence of AlBr₃ catalyst

(A) bromobenzene (B) n-propylbenzene (C) iso-propylbenzene (D) o-bromo-n-propylbenzene

(E) p-bromo-n-propylbenzene

19. Which of the following is the electrophile in the nitration reaction

(A) ⁺HNO₂ (B) NO₂⁺ (C) N₂+ (D) HNO₃/H₂SO₄ (E) NO₃⁺

20. Which of the following is the electrophile in the sulfonation reaction

(A) ⁺HSO₂ (B) SO₂⁺ (C) SO₃⁺ (D) SO₃/H₂SO₄ (E) HSO₃⁺

21. Which of the following is the electrophile in the Friedel-Craft acylation reaction

(A) RCO₂⁺ (B) RCO⁺ (C) CO₂⁺ (D) RX/H₂SO₄ (E) RCO₃⁺

22. The benzyne intermediate has ï¿½ï¿½ p bonds

(A) 1 (B) 2 (C) 3 (D) 4 (E) 5

23. The reagent used for Allylic/benzylic bromination is:

(A) NBS (B) Br₂/ Fe (C) Br₂/ AlBr₃ (D) Br₂/ FeBr₃ (E) Br₂/ HBr

24. Which of the following is an oxidation reagent

(A) H₂SO₄ (B) KMnO₄ (C) KMnO₂ (D) NaBH₄ (E) AlCl₃

25. The formula of fuming sulfuric acid

(A) H₂SO_4.SO₃ (B) H₂SO_4.SO₂ (C) H₂SO_4.HSO₂ (D) H₂SO_4.HSO₃ (E) H₂SO_4.SO

26. How do you prepare the following compounds, starting from benzene ?

(a). aniline (b). Iodo benzene (c). benzoic acid (d). benzylbromide (e). m-methyl benzoic acid

(f). p-nitrobenzoic acid (g) m-nitrobenzoic acid (h). p-chlorobenzenesulfonic acid (i). m-chlorobenzenesulfonic

acid (j) 3-isopropyl benzoic acid (k). 4-isopropyl toluene

27. Draw the product(s) from the following reactions showing the mechanisms

(a) 1,3-butadiene with acrylonitrile

(b) 1,3-butadiene with one eqv. HBr

(d) 1,3-cyclohexadiene with one eqv. HBr

(e) 1,3-cyclohexadiene with two eqv. HBr

(f) cyclopentadiene with two eqv. HBr

28. How do you prepare the following compounds, starting from toluene ?

(a). benzoic acid (b). benzyl alcohol (c). m-bromobenzoic acid (d). m-methylbenzoic acid (e). m-nitro

benzoic acid (f). p-nitrobenzoic acid

29. What is/are the product(s) expected when ethylbenzene is reacted with

(a). NBS

(b). Br₂/FeBr₃

(c). KMnO₄, then H⁺

(d). fuming H₂SO₄

(e). NBS, then aq. NaOH

(f) iso-butylbromide/AlBr₃

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CHEM 2312 Midterm: CHEM 2312 GT Examp2ii

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