CHEM 2211 - Midterm #2

Sample Questions (from fall 2002 midterm) - NOTE: I have only included those questions on topics we have covered to this point

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Part A: Multiple Choice (15 questions, worth 1 each)

 
1.
(i) What is the IUPAC name for this compound?

CH3OCH2CH=CH2

 (a) 3-methoxypropene
(b) 1-methoxy-2-propene
(c) allyl methyl ether
(d) methyl vinel ether
(e) dihydropyran
 
(ii) What is the IUPAC name for this compound?

(a) (E)-(2R)-penten-2-ol
(b) (Z)-(2R)-penten-2-ol
(c) (E)-(2S)-penten-2-ol
(d) (Z)-(2S)-penten-2-ol
(e) none of the above
 
(iii)What is the IUPAC name for this compound?
(a) (2S, 3R)-2-chloro-3-pentanol
(b) (2R, 3R)-2-chloro-3-pentanol
(c) (2S, 3S)-2-chloro-3-pentanol
(d) (2R, 3S)-2-chloro-3-pentanol
(e) none of the above
 
(iv)What is the IUPAC name for this compound?

(a) 1-bromo-2-hexyn-5-ol
(b) 6-bromo-2-hydroxy-4-hexyne
(c) 1-bromo-5-hydroxy-2-hexyne
(d) 5-bromo-1-methyl-3-pentyn-1-ol
(e) 6-bromo-4-hexyn-2-ol
 
3.  Which statement is true about all S isomers?
(a) they are levorotatory
(b) They are mirror images of R enantiomers
(c) they consist of equal parts of (+) and (-)
(d) they are dextrorotatoty
(e) the are racemic mictures
 
5. Zaitsev's Rule states:
(a) In an electrophilic addition of an unsymmetric reagent to an unsymmetric alkene, the more positive portion of the reagent will become attached to the carbon of the double bond bearing the greater number of hydrogen atoms.
(b) An equatorial substituent in cyclohexane results in a more stable configuration than if that substituent were axial.
(c) E2 reactions occur only if the b-hydrogen and the leaving group can assume an anti-periplanar arrangement.
(d) When a reaction forms an alkene, and several possibilities exist, the most stable isomer is the one that predominates.
(e) The order of reactivity of alcohols in dehydration reactions is 3o>2o>1o
 
6. Which compound is optically active?
(a)  3-chloropentane
(b)  3,3-dichloropentane
(c)  1-chloro-2-methylpentane
(d)  2-chloro-2-methylpentane
(e)  1,5-dichloropentane
 
8. Predict the major product(s) for the following reactions:
 
(a)
 
NOTE: there were 3 more questions here, on topics we have not covered this year.
 
9. Determine the number of chirality centres and the maximum number of possible stereoisomers of 3,4-dichlorocyclohexene.  Draw all the stereoisomers.  If, while drawing these, the maximum number cannot be reached, explain why.
 
10. The two reactions, at first glance, might both be used to prepare MTBE (methyl tert-butyl ether), a gasoline additive, via and SN2 reaction.  Only one of these reactions actually produces the desired MTBE.  Explain which one and why.
(CH3)3C-O- K+   +   CH3-Br   --->   (CH3)3C-O-CH3   +   KBr

(CH3)3C-Br   +   CH3-O- K+   --->   (CH3)3C-O-CH3   +   KBr
 
12. Draw the transition state for an E2 elimination reaction.  Use 2-bromo-2-methylpropane and sodium ethoxide (CH3CH2O-Na+) as the reagents involved in the reaction.
 
13. Devise a method for accomplishing the following transformation.  You will need at least 3 steps.  You do not have to show a mechanism.
 
14. Complete the following reactions, including a detailed, step-by-step mechanism for each.
 
(a)
 
(b) one more on material we didn't cover this year


 

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