Second Exam, March 3, 1999
1. (8) Give correct IUPAC names for the following compounds. Include R or S designations for stereochemistry where necessary.
2. (8) Draw structures which correspond to the following IUPAC names. Where R or S designations are given, you may answer either in a perspective or a Fischer formula.
|a. 2-phenylbutanoyl chloride||b. (S)-2-pentanol|
3. (16) a. Circle the meso compound. Underline its diastereoisomer.
b. Circle the reducing disaccharide. Underline the non-reducing disaccharide.
c. Circle a pair of structures which are enantiomers. Underline a pair of structures which are diastereoisomers.
d. Circle the a (alpha) anomer. Underline the b (beta) anomer.
4 (24) Write structural formulas for the products of the following reactions.
5. (18) For each of the following reactions, place the structure of the needed reactant in the box.
6. (10) Show how you could carry out the following synthetic scheme by listing the necessary reagents in the proper sequence.
7. (8) Write out the steps in the mechanism for the formation of the tetrahedral intermediate in the acid catalyzed (Fischer esterification) reaction of propanoic acid with 1-butanol. The overall reaction is shown below. (You need not show the steps which lead from the tetrahedral intermediate to the final product.)
8. (8) Erythrose is a D-aldotetrose which is reduced to an optically inactive compound (called erythritol) by sodium borohydride. If the Kiliani-Fischer chain extension reaction is applied to erythrose, two stereoisomeric products are formed. One, A, is reduced to an optically inactive product by treatment with sodium borohydride. The other, B, is reduced to an optically active product by similar treatment. Give structures for erythrose and compounds A and B.
Kiliani-Fischer chain extension - an example.