Last NAME:______________________________________________ First
Cornell University Chemistry 357 Fall 2004 Examination II October 19, 2004 Instructions: Read all questions completely before answering.. You may find it helpful to first answer those questions that you find easier and then return to those you find more difficult. The proctors are not permitted to answer any questions about the exam. Please follow the directions for each question as answers that are not written where or how it is specified in the question will lose all credit. Good Luck!!!
Problem 1 2 3 4 5 6 7 8 9 10 11 TOTAL
Score
Possible 10 9 10 10 10 5 11 16 4 10 5 100
Signature:________________________________________________
Page 1 of 8 1) (10) Provide IUPAC names for each of the following structures and write your answer on the line to the right of the structure. Be sure to include any appropriate stereochemical designations.
a)
Br
H
H
b)
H3C
H
H3CH2C CH3
CH3
c)
Br F I
Cl
d)
e)
Page 2 of 8 2) (9) For each of the compounds shown below, write its relationship (i.e. enantiomer, diastereomer, same, different, structural isomer, etc) to (2S, 3R) 2-chloro-3methylpentane. Write your answer on the line below each compound.
CH2CH3 Cl H3C CH3 H H
CH2CH3 H Cl CH3 CH3 H H H
CH2CH3 CH3 Cl CH3
Cl H CH3 H H3C H3C H CH2CH3 Cl
CH3 H H H Cl CH3 H H3C H
CH3 Cl H H H3C H3C H CH3 Cl H
-O
NH2 N O P O OH H O H H H N O
H
H
OH
Page 3 of 8 3) (10) Propose a reasonable mechanism to account for the formation of the following product(s).
Br2
H Br Br H
4) (10) Propose a reasonable mechanism to account for the formation of the following product(s).
H3C H H OH H H
1) BH3 2) H2O2 , NaOH H2O
H3C H3C
H3C
H
Page 4 of 8 5) (10) Propose a reasonable mechanism to account for the formation of the following product(s).
CH3
HCl
CH3 Cl
6) (5) Rank the following alkenes in terms of their overall stability, with 1=most stable and 5=least stable. Write answer your on the line below each alkene.
Page 5 of 8 7) (11) There is a cyclooctene with two substituents on the ring, call it Compound Y. Compound Y has the molecular formula C12H22. It undergoes the following reactions to produce the number of unique carbon-containing products indicated by the number of boxes for each reaction. The products (indicated by the boxes) are described as either chiral or achiral and their relationship to each other is indicated. Draw the starting material in all of the Compound Y boxes and then draw the products from each reaction in the product boxes so that all of the stereochemical descriptions are accurate.
H2SO4 H2O
+
Compound Y
achiral diastereomers
achiral
1)BH3 2) H2O2, NaOH, H2O
+
Compound Y
chiral diastereomers
chiral
1) O3 + 2) CH3SCH3 H3C
O S CH3
Compound Y
Chiral
Page 6 of 8 8) (16) In the diagram below, draw the structure(s) of the product(s) from each reaction where you are given the reagents that are added to the starting material. When the product is shown instead, write (draw) the structure of the reagent(s) necessary to produce the indicated product in the box over the arrow.
H
CH3
NaOH
H
CH3
1) Zn CH (C 2 I u) 2
HBr Heat
O O
Br 2
KMnO4
H2SO4 H2O
,H
2O
H 3 aO BH ,N 1) O2 H 2 2O H
2)
H3 C H3C
O
H H
Page 7 of 8 9) (4) Rank the following carbocations in terms of their stability (1= most stable, 4=least stable). Write your answer on the line below each carbocation.
H C+ H H C+ H3C
CH3 C+ CH3 H C+ H H
10) (10) Propose a reasonable mechanism to account for the formation of the following product(s). Br H H3CH2CH2C H3CH2CH2C H HBr
H3CH2C H HOOH ! H3CH2C H H
Page 8 of 8 11) (5) Draw an alkene, that when subjected to the following series of reactions, produces only the carbon containing products that are shown below. Draw your structural answer for the starting material in the box.
1) O3 2) CH3SCH3 H
O
O
O + H H3C
O S CH3