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Practice Exam 3

1. (19 pts)

(a) Circle the group with the higher Cahn Ingold Prelog priority in each of the following pairs (6 pts.).

CH2

and CHC

and

CH2 and

NCH2 CH3

CH3

1)

2)

3)

Br

OH

H3C

NHCH3

(b) The sex attractant of the codline moth is the 2Z, 6E stereoisomer of the molecule below. Write thestructure of this substance in a way that clearly shows its stereochemistry. (4 pts).

CH3CH2CH2C=CHCH2CH2C=CHCH2OH

CH3 CH2CH3

(c) Provide the IUPAC names for the following compounds. Be sure to designate E or Zstereochemistry for part (i) (6 pts).

(i) (ii)

Cl

OH

(d) Draw a structure for the following molecule (3 pts):

4-methyl-4-penten-2-ol

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2. (38 pts) Draw the principal organic product expected from each of the following reactions. If more than oneproduct is expected, be sure to indicate which is the major product. Pay particular attention toSTEREOCHEMISTRY AND REGIOCHEMISTRY where appropriate.

(a)

CH3

Br

CH3

HK+ -OC(CH3)3

HOC(CH3)3

(b)H2SO4

HOC(CH2CO2H)2

CO2H

citric acid

(c)

CH3CH2O-Na+

CH3CH2OH

CH3Br

(d)

KHSO4

heat

HO CN

H3CO

(e)

2-methyl-2-buteneperoxides

HBr

(f)

H2

Pt

CH3

CH3

Which reaction part above involves a non-Zaitsev elimination?_________ (2 pts)

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(g)

H2O

Br2CH3

(h)O

OO

H

Cl

(i)

HCl

(j)

H2SO4

(catalyticamount)

CH3

H2O

(k)CH3

CH3

B2H6 H2O2

NaOH

(l)

1. O3

2. (CH3)2S

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3. (13 pts ) Complete the following questions:(a)The carbocation below has the potential to rearrange to a more stable carbocation. Write the structure of therearranged carbocation (3 points).

(CH3)2CH CH CH3

(b) Draw out the alkenes you would expect to get from the E2 elimination of 2-bromo-2-methylpentane (4pts).

(c) The reaction of 1-butene with bromine, Br2, in aqueous solution gives primarily 1-bromo-2-butanol.Identify the nucleophilic species in the reaction (3 pts). A. Br2B. Br C. H2OD. HOBr

(d) Which of the following alkenes is expected to have the highest heat of hydrogenation (circle the correctanswer (3 pts)?

A. 1-penteneB.trans-2-penteneC.cis-2-penteneD.2-methyl-2-butene

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4. (16 pts)

(a) (9 pts) Compounds A is an alcohol of molecular formula C6H14O. On being heated with sulfuric acid, a majoralkene B and a minor alkene C are formed. Ozonolysis, followed by treatment of the ozonide with dimethylsulfide,of major alkene B gives acetone (structure shown). What are the structures of compounds A and B and C. Brieflyexplainhow you arrived at your answer (you can answer this by showing reactions).

H3C CH3

O

acetone

Is acetone and aldehyde or ketone? ________________ (1 point)

(b) (6 pts) Outline a sequence of reactions that would be suitable for the preparation of the following compound fromindicated starting material and any needed reagents. The synthesis will require more than one step.

1-bromo-2-propanol from 2-propanol

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5. Mechanisms(14 pts)(a) Provide a stepwise mechanism, using arrows to show electron movement, to account for the formation of the

product in the following reaction. (6 pts)

IBr

Br

I

(b) Provide a stepwise mechanism, using arrows to show electron movement, to account for the formation of theproducts in the following reaction. (8 pts)

+H3O

+OH

+

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