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Organic Chem. I. Summer 2011, Midterm-2, Prof. Moon Name: P-ID: _____________ Last Name, First Name Signature_______________________________________ Clearly indicate your answers in the spaces provided; if we have to guess as to what or where your answer is, it's wrong. Make sure your name is on each page of the examination; the management is not responsible for lost pages. Your signature above is your assurance that you have worked independently. You are strongly advised to read the exam through completely before you begin. Total # of Questions: 22 x 3.5 pts = 77 pts Short answer questions: 26 pts

1. What is the major product of the reaction,

Br

(CH3)3COK

(CH3)3COHheat

?

A) (CH3)2C=C(CH3)2 D) (CH3)2C=CHCH2CH3 B) (CH3)3C–CH=CH2 E) None of these C) (CH3)2C=CHCH3

2. By analyzing the starting material and the product(s), the following reaction is possibly an example of what type of mechanism?

Br N3

+N3

A) SN1 B) SN2 C) E1 D) E2 E) More than one of the above

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3. I and II are:

I II

H

OHH3CH2C

ClBr

CH2CH2CH3 CH2CH3

HO H

Cl Br

CH2CH2CH3

A) constitutional isomers. D) diastereomers. B) enantiomers. E) not isomeric. C) identical.

4. What is the major product for the following reaction?

a. BH3:THF

b. H2O2, NaOHA)

+ enantiomerOH

D) + HCHO

O

H

B)

E)

OH C)

OH

5. Which of the following carbocations would NOT be likely to undergo rearrangement? A) CH3CHCHCH3

CH3

D) CH3CHCH2

CH3

B) CH3CHCCH3

CH3

CH3

E) CH3CCHCH2CH3

CH3

CH3

C)

CH3CCH2CH3

CH3

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6. What would be the major product(s) of the following reaction?

CH3H3C

H Br

CH3H3C

H OCH3

OCH3H3C

H CH3

I II

H3C CH3 H3C

III IV

CH3O− / CH3OH

55oC

A) I B) II C) III and IV D) I and II E) All of the above

7. What is the major product for the following reaction?

a. Hg(O2CCF3)2, CH3OH

b. NaBH4, NaOHA)

+ enantiomerO

D) O

B) + enantiomer

O

E) None of the above

C) OH

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8. The compounds whose molecules are shown below would have: CH3

F

FH

CH3H

F

FH3C

CH3

H

H

A) the same melting point. D) More than one of the above B) different melting points. E) None of the above C) equal but opposite optical rotations.

9. Which of the following reactions would yield 2-pentyne? A) I

(1 mol)

NaNH2

B) NaNH2 Br(1 mol)

C) Br

Br

CH3OH

D)

OH

HAheat

E) BrNaOC2H5C2H5OH

10. What is the major product for the following reaction sequence? 1a. NaNH2, NH3 (liq.)1b. CH3CH2CH2Br

2a. Li, CH3CH2NH22b. NH4Cl

A) D)

B) CH3CH2CH2Br E) None of the above

C)

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11. What will be the major product of the following reaction?

OH

85% H3PO4

heat?

A)

D) O

B)

E)

C)

12. Consider the SN2 reaction of 1-chloro-5-methylhexane with CN– ion.

Cl NaCN CN NaCl Assuming no other changes, what effect on the rate would result from simultaneously doubling the concentrations of both 1-chloro-5-methylhexane and CN– ion? A) No effect. D) It would increase the rate four times. B) It would double the rate. E) It would increase the rate six times. C) It would triple the rate.

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13. What is the major product for the following reaction?

a. BH3:THF

b. H2O2, NaOHA)

+ enantiomerOH

OH

D)

OH

B)

H

O

O

E)

+ enantiomer

OHC)

+ enantiomer

OH

14. The major product of the following reaction would be: C H 2 C l

H O C H 3

C H 3

O H −

C H 2 O H

H 3 C O H

C H 3

C H 2 C l

H O H

C H 3

I

I I I IV

C H 2 C l

H O H

C H 3

I I

C H 2 O H

H O C H 3

C H 3

S N 2?

A) I B) II C) III D) IV E) An equimolar mixture of I and II.

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15. What is the major product for the following reaction?

HBr

A)

Br

+ enantiomer

B)

Br

+ enantiomer

C) Br+ enantiomer

D)

Br+ enantiomer

E) More than one of the above

16. What is the major product of the following reaction sequence? 1. HI

2. t-BuOK, t-BuOHA)

D)

B)

E) More than one of the above

C)

17. Which is the strongest nucleophile?

A) OH- B) CH3CH2O- C) D) CH3CH2OH E) H2O

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18. Predict the product(s) for the following reaction sequence. 1. NaI, acetone

2. CH3CO2Na, CH3CO2HClA)

D)

B)

O O

E) A mixture of A) and D)

C)

O O

19. Which statement is not true for a meso compound? A) The specific rotation is 0º. B) There are one or more planes of symmetry. C) A single molecule is identical to its mirror image. D) More than one stereogenic center must be present. E) The stereochemical labels, (R) and (S), must be identical for each stereogenic

center.

20. The molecules below are:

Br

FCl

CH3

I

CH3

FBr

Cl

IIA) constitutional isomers. D) identical. B) enantiomers. E) None of these C) diastereomers.

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21. The correct IUPAC name for the following compound is:

Br

Cl

A) (E)-2-Bromo-3-chloro-5-methyl-2-hexene B) (E)-2-Bromo-3-chloro-5-methyl-3-hexene C) (Z)-2-Bromo-3-chloro-5-methyl-3-hexene D) (Z)-2-Bromo-3-chloro-5-methyl-2-hexene E) (E)-2-Methyl-5-bromo-4-chloro-4-hexene

22. What can be said with certainty if a compound has [α] 25D

= -9.25 ? A) The compound has the (S) configuration. B) The compound has the (R) configuration. C) The compound is not a meso form. D) The compound possesses only one stereogenic center. E) The compound has an optical purity of less than 100%.

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Answer Key

1. B 2. A 3. D 4. E 5. C 6. C 7. D 8. B 9. B

10. C 11. A 12. D 13. E 14. B 15. C 16. B 17. B 18. C 19. E 20. D 21. A 22. C