1CHE 230 Organic ChemistryExam 2, October 20, 1999Name Student ID No. Before you begin this exam: First: You are allowed to have a simple model set at your seat.Please put away all other materials. Second: Place your student identification on your desk. Aproctor will come around to check everyone’s ID. Third: Read through the entire exam. Yourgoal, as always, is to score as many points as possible. Do not waste time on problems that youcan’t do if there are others that look easy. Fourth: It is critically important that your answers bewritten in a clear, unambiguous manner. Answers in which your intentions are unclear will notreceive credit. Fifth: READ THE INSTRUCTIONS FOR EACH PROBLEM.If you wish to have your exam score posted beside your student ID number in the glass case (1stfloor, CP Building, behind CP-139) with the exam key, place an ‘X’ in this space . Ifyou do not mark this space, your exam score will not be posted.You have until 8:50 to complete this exam. There will be no extensions, so budget your timecarefully.Problem Number Points possible Score1. 15 2. 10 3. 20 4. 8 5. 10 6. 9 7. 20 8. 8 Total 10021. (15 points) Assign the configuration at all stereogenic centers in the following compoundsusing the R,S convention.a)CH3BrHCH3CH2b)H2NNHOCO2HOOCH3 (Aspartame, a sweetener)c)OHHH3CO OHd)CH3HHOO H2. (10 points) Assign the E,Z configuration at all of the alkenes below.a)CH3H CH3CH2CH3b)F3c) (Do all 3 C=C double bonds in this example)CCCOCCSCCNHCNHCCNCCCH HHHHH HHHHH H H HH HHHHH NOO(Zantac, anti-stomach acid medication)3. (20 points) Consider the conformations of 2-methylbutane. Construct a qualitative potentialenergy diagram for 360 degree rotation about the C2-C3 bond in this compound. Youranswer must show the Newman projections for the conformations that correspond to the 6energy minima and maxima.23Energyθ44. (8 points) Which of the following compounds are chiral? (Circle the chiral ones)OHOHOHCH3OHOH OHC C CCH3HHBrC C CCH3HHHOHOHOHOH5. (10 points) There are three stereoisomers of tartaric acid; two that are enantiomers and adiastereomer that is meso. Draw the meso diastereomer (wedge-and-dash or sawhorsedrawing) and show the plane of symmetry with a dashed line. Be sure that you draw anappropriate conformation that allows you to clearly show the plane of symmetry. A wedge-and-dash or a sawhorse drawing would be appropriate.CCHCHCOHOOOHOHOHTartaric Acid6. (9 points) Draw the structures that correspond to the following names.a) 1-(1-chloroethyl)-cyclopentene5b) (R) 2-chlorobutanec) Z 1,fluoro-1-propene7. (20 points) Draw the following compounds in their most stable chair conformation. Besure that your drawing clearly shows which groups are axial (if any) and which areequatorial (if any).a)O OHOHHOOHHOCH2(β-D-glucose)b)c)68. ( 8 points) In two words or less, state the relationship between the pairs of compoundsbelow. (For example, if one pair of compounds are enantiomers, write ‘enantiomers.’ Ifthey are identical, write ‘identical’, or ‘the same.’)OOThese compounds are OCH2OHHOHOHOOHOCH2OHHOHOOHOHThese compounds are C C CCH3HBrHCCCCH3HBrHThese compounds are These compounds are END OF
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