1CHE 230 Organic ChemistryExam 2, March 8, 2000Name Student ID No. Before you begin this exam : First: You are allowed to have a simple model set atyour seat. Please put away all other materials. Second: Place your studentidentification on your desk. A proctor will come around to check everyone’s ID.Third: Read through the entire exam. Your goal, as always, is to score as manypoints as possible. Do not waste time on problems that you can’t do if there areothers that look easy. Fourth: It is critically important that your answers be writtenin a clear, unambiguous manner. Answers in which your intentions are unclearwill not receive credit. Fifth: READ THE INSTRUCTIONS FOR EACH PROBLEM.If you wish to have your exam score posted beside your student ID number in theglass case (behind CP-139) with the exam key, place an ‘X’ in this space . If you do not mark this space, your exam score will not be posted.You have until 9:50 to complete this exam. There will be no extensions, so budgetyour time carefully.Problem Number Points possible Score1. 15 2. 14 3. 8 4. 5 5. 12 6. 22 7. 15 8. 92Total 100 1. (15 points) Classify the relationship between each pair of structures as eitherskeletal isomers, conformational isomers, enantiomers, or diastereomers.a)CH3ClClCH3 b)Cl Clc)Cl ClCl Cld)CHOOHHHOHCH2OHHOCH2CHOOHOHe)32. (14 points) Assign the R, S convention to the indicated stereogenic centersand assign the E, Z convention to the indicated C=C bonds.a) NCH3NHCH3ONLysergic Acid Diethylamide (LSD)b)4HOOHOCO2HProstaglandin E23. (8 points) Classify each of the following compounds as either chiral orachiral.a)NNNicotineb)OPSFCH3NVX, the most potent nerve gas in the US arsenalc)5CO2HOCH3Oo-Acetylsalicylic acid (aka Aspirin)d)NNNO2NNO2NO2HMX (“Her Majesty’s Explosive”)4. (5 points) Which one of the structures below is the meso isomer of 2,3-dihydroxybutane? (Circle it)OHOHOHOH5. (12 points) Draw a Newman projection of the most stable conformation ofeach of the following compounds:a) cis-1,3-dichlorocyclohexaneClCl6b) 2-methylbutane (sight down the C2-C3 bond)H3CCH3CH3c) trans-4-bromo-methylcyclohexaneBr76. Newman projections I - VI of (d,l)-3,4-dimethylhexane are shown below. Allof these are sighting down the C3-C4 bond.a) (5 points) Which one of the eclipsed conformations is of the highestenergy? (Circle it)HCH3CH2CH3CH2CH3HCH3HCH3CH2CH3HCH3H3CH2CHCH3CH2CH3CH3CH2CH3HIII IIIb) (5 points) Which one of the staggered conformations is of the lowestenergy? (Circle it)HCH3CH2CH3CH2CH3HCH3HCH3CH2CH3HCH3CH2CH3HCH3CH2CH3CH3CH3CH2HIV V VIc) (12 points) Draw a rotational energy diagram for 360 degree rotationaround the C3-C4 bond of (d,l)-3,4-dimethylhexane. Your energy diagramshould clearly indicate the relative energies of conformations I - VI. Astarting point (conformation IV) has been provided.EθθθθIV87. (15 points) Draw each of the following cyclohexane derivatives in their moststable chair conformation.a)b)c)HH98. (9 points) How many stereoisomers are there of each of the compoundsshown below? (NOTE: this question does not ask for the maximum numberpossible. You are to determine how many stereoisomers can be drawn foreach compound)a)CH3CH3b)c) (careful with this one....)CH3END OF
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