Chemistry 230–002 Second ExaminationOctober 23, 2003Name (please PRINT LEGIBLY) (last) (first)Student ID # Problem Score1. (a-d) /202. (a-f) /303. (a-e) /254. (a–c) /155. (a-b) /10Total /100Please observe the following.1) Write LARGE and LEGIBLY.2) Read each question carefully before answering. Many points are never awarded on every exambecause students do not read the instructions.3) Explanations muct be clear, coherent, and unambiguous to receive credit.4) For questions with multiple parts, be consistent. Your answer to a later part will be graded based onthe earlier part being correct, whether or not it actually is. For example, suppose I asked the followingquestions:(a) What is the hybridization of methane? (5 pts)(b) What is the H–C–H bond angle? (5 pts)Three students gave the following answers:Student 1 Student 2Student 3(a) sp2sp2sp3(b) 120° 109° 109°Score: 0 pts + 5 pts 0 pts + 0 pts 5 pts + 5 ptsStudent 1 correctly answered (b) given her answer for (a). Student 2 incorrectly answered (b) given hisanswer for (a), even though (b) is formally correct. Student 3 correctly answered both (a) and (b) and gotfull credit for the question.page 11. (20 pts. total.) (a) (6 pts.) Assign the configurations of the two stereocenters in thecompound below.OOPhOHH2NNH(b) (4 pts.) Draw a configurational diastereomer of the compound above.(c) (6 pts.) Circle the chiral compounds in the list below.HOCl ClCl ClCl ClClClCl Cl Cl ClBr Cl Cl ClCl Cl Cl(d) (4 pts.) Circle the compound below whose name is (S,E)-4-chloro-3-hexen-2-ol.OH ClClOH OH ClClOHpage 22. (5 pts. each, 30 pts. total.) Describe the relationship of each pair of structures as specificallyas possible and in no more than two words.(a)t-Bu t-BuFF(b)ClNMe2ClNMe2(c)H3CCO2HOHNH2H3CCO2HOHNH2page 3(d)ClOH OH Cl(e)HNOOHOCH3NH2HOHNCH3ONH2HOOOH(f)PhPhPhPhpage 43. (25 pts. total.) I hope you practiced drawing your chairs!(a) (4 pts.) Draw trans-4-isopropylcyclohexanol in planar form (no chair). Be sure to indicatethe stereochemistry.(b) (6 pts.) Now draw trans-4-isopropylcyclohexanol in its lowest energy conformation.(c) (5 pts.) Now draw cis-4-isopropylcyclohexanol in its lowest energy conformation.page 5(d) (5 pts.) Based on your answers to (b) and (c), is trans-4-isopropylcyclohexanol higher inenergy, lower in energy, or about the same energy as the cis isomer, or is there no way totell? Explain your answer briefly (one sentence).(e) (5 pts.) Using the table below, compute the approximate difference in energy between thestructures you drew in (b) and (c).GroupCost of single 1,3-diaxialinteraction with HOH 0.45 kcal/molCH30.85 kcal/mol1° alkyl (e.g., Et) 0.90 kcal/mol2° alkyl (e.g., i-Pr) 1.1 kcal/mol3° alkyl (e.g., t-Bu) 2.7 kcal/molApproximate difference in energy:page 64. (5 pts. each, 15 pts. total.) Undergraduate researcher Sally Humdinger acquires a sample of(R)-2-chlorobutane of 50% ee. She measures its specific rotation, [α], to be –30°.(a) What would [α] be for an enantiomerically pure sample of (S)-2-chlorobutane? Indicatethe sign and the magnitude, and explain your reasoning.(b) If Sally converts her (R)-2-chlorobutane to (S)-2-aminobutane, would you predict that theproduct would be dextrorotatory, levorotatory, or optically inactive, or would there be noway to tell? Explain your answer.(c) Sally wants to make some enantiomerically pure (R)-2-chlorobutane, so she suggestscombining butane with Cl2 to give 2-chlorobutane. She asks you whether her scheme willwork. Explain to her whether her scheme will work, and why.page 75. (5 pts. each, 10 pts. total.) You travel in a spaceship to the distant planet Htrae, where allmolecules are mirror images of the ones here on Earth. NASA has forbidden smoking on itsspacecraft, and you’re addicted to nicotine, so when you arrive at Htrae you need a smoke,bad. A Htrae life form offers you a drag on the local version of the nicotine delivery device.(a) Will you feel much better after smoking the Htrae cigarette, much worse, just the same, oris there no way of predicting? Explain your answer briefly. The structure of Earth nicotine isshown below.(b) Will the smoke from the Htrae cigarette be more, less, or just as carcinogenic than thesmoke from an Earth cigarette, or is there no way of predicting? Explain your answer briefly.The structure of one of the major carcinogens found in Earth cigarette smoke is shown below.NNMeHNicotineBenzo[a]pyrene, a typical cigarette
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