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004:121 Final Exam Spring, 2002 May 14, 2002 Name (please print): _____________________________ Signature: ___________________
Student ID #: ______________________
Please check to make sure there are eight pages (not including this cover page) in this exam booklet. Thereare a total of ten questions. Answer the questions in ink in the spaces provided. Use the backs of the pages for additional space or scratch paper if needed. Remember no re-grades for RED ink or pencil. Also NOCHEATING!
Good Luck!
And Have a GREAT Summer!
Total: _______________
- The following questions relate to the structures A-F below. Some questions may have more than one correct answer (if so, give all of them). If there is no correct answer among the choices write “none”.(22 points)
a. Which of the above contain(s) a ketone group? __________ b. Which of the above contain(s) an ester group? __________ c. Which compound(s) above would have a pKa = ~5? __________ d. Would compound C be a polar molecule? _________ e. Which would give a strong absorbance peak(s) near 1700 cm-1^ in an IR spectrum? ________ f. How many different signals would you expect in the^1 H NMR spectrum of structure F? _______ g. How many different signals would you expect in the^13 C NMR spectrum of structure A? _______ h. Which molecule(s) has/have chiral carbons? ______________ i. For compound B what would be a most likely fragment loss? ______________ j. Which of the above would give a mass spectrum containing an ion two mass units higher than M+, and approximately equal in intensity as M+? __________ k. Which of the above compounds would be the most likely to undergo an SN2 reaction? (most reactive) __________
CH 2 CH 3
CH 2 NHCH 3
Br
H 3 CH 2 C O
O
OH
H 3 C CH^3
O
OH
CH 2 Cl
A B
C
D
E
F
H
I
H
OH C H H 3 C OH CH 3
O
HO
c.
- meso, (^) orIndicate whether the following pairs of structures are identical. (Use the best term to describe the relationship of the pairs here.) (9 points) enantiomers , diastereomers , structural isomers ,
a.
b.
c.
C C (^) CH 3 H 3 C H
H
HO Cl C C (^) H HO Cl
H
H 3 C CH 3
HO CH 3
Cl CH^3
HO
Cl
CH 3
H 3 C
H 3 C
OH
CH 3
H
H (^) OH
H 3 C
H
HO OH
H
CH 3
- a. The compound below can be obtained as a product of a Diels-Alder reaction. Draw the diene and the dienophile that must be combined to yield this product. (8 points)
b. Which type of product is shown above: endo, exo, or neither? _________________
- Write the major organic product(s) for each of the following reactions in the box provided. Be sure to clearly indicate all stereochemistry where relevant. All reagents listed are present in excess unless otherwise noted. If you expect no reaction between the reactants given, write, "NR". (28 points) a.
b.
H 3 C H
O NaBH4, H2O
O
O
O
H
H
HBr Peroxides
- Write the missing reagent(s) or starting material(s) for each of the following reactions in the box provided. Be sure to clearly indicate all stereochemistry where relevant. If the conversion is not possible,write “NR”. If the reaction needs to take place in more thank one steps make sure you label them as such. (18 points)
a.
b.
c.
d.
e.
H
? H
? H
OH
H
OH
H OH Cl
H
OH
OH
+ Enantiomer
Br
CH 3
? CH^3
f.
- a. Draw the transition state for the rate-determining step of the E2 reaction of the compound below with NaOEt. Be sure to show all partial charges and bonds, and place all atoms in proper "3D" orientations. (21 points)
In parts b and c below, two species are poised to react with each other. Draw in the appropriate"mechanistic" arrows to show how they will react with each other, and then draw the key organic intermediate or product formed after the step shown. Arrows must be drawn precisely to obtain credit. b.
c.
H
H
O
OH
O
OH
H
H
CH 3
Br
H 3 C
CH 3 CH 2
HO Br
CH 2 CH 2
Br
H Br
- Provide a structure for the compound that gives the spectral data shown in the following problem. Partial credit is possible for correct partial structures or partial work only if your answers are placed in theappropriate labeled box below. The NMR shift tables from the text can be found on the last page of the exam. (10 points) Molecular Formula Degrees of Unsaturation
Fragments Structure
Proton NMR
4 H 2 H
3 H
1 H
2 H
C
C
CH
CH
CH 2
CH 2 CH 3
