CHEM3331: Fundamentals of Organic Chemistry I Final Exam Prof ...

CHEM3331: Fundamentals of Organic Chemistry IFinal ExamProf. Ognjen Š. Miljanić December 11, 2012Name:LastFirstStudent ID Number:Read all directions very carefully, think about your answer, and then write it legibly in the designated spaces.Total number of points is 390.1. For each of the following reactions or series of reactions, draw the structure of the major product(s) in thebox. Be sure to clearly indicate stereochemistry where this is pertinent. If you think that no reaction occurs, write"No Reaction".15 × 8 = 120 pointsF I N A L S C O R E1D O N O TW R I T EI N T H I SS P A C E

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2. Give detailed mechanisms for the two reactions presented below. Show all charges and intermediates, and usecurved arrows to indicate the flow of electrons. Do not draw transition states.40 + 20 = 60 points4D O N O TW R I T EI N T H I SS P A C E

3. Name the following compound according to IUPAC's systematic nomenclature. Indicate the stereochemistryof chiral centers and/or C=C double bonds where needed.5 × 8 = 40 points5D O N O TW R I T EI N T H I SS P A C E

4. For each of the following two conversions, give a step-by-step outline of a synthetic sequence which wouldefficiently accomplish the required transformation. You may use any organic compound with two or lesscarbons, and any inorganic reagent. Do not give mechanisms.2 × 30 = 60 points6D O N O TW R I T EI N T H I SS P A C E

5. Draw both chair conformations for the molecule shown below (D stands for deuterium, the heavier isotope ofhydrogen). Circle the more stable conformation. Then, predict the product of E2 elimination of this precursor.Explain your reasoning in one brief sentence.30 pointsHINT: does H or D get eliminated?7D O N O TW R I T EI N T H I SS P A C E

6. This question has several parts. In each segment, circle only one answer. 5 × 4 = 20 pointsCircle the strongest base among the following anions:OO S NHOCircle the most electronegative element:Na B N Li Pb Hg CCircle the most stable radical:Circle the only enyne among the following four compounds:Which compounds produce tertiary alcohols when reacted with Grignard reagents?alkanes aldehydes ketones alcohols ethers8D O N O TW R I T EI N T H I SS P A C E

7. Molecule A has molecular formula C 8H 10. Its 1 H NMR spectrum shows a doublet at 1.28 ppm (integrates for6H), a quartet at 2.70 ppm (integrating for 2H), and a singlet integrating for 2H at 2.83 ppm. Its 13 C NMRspectrum contains four peaks, and its characteristic IR bands are found at 2215 (weak), 2950, and 3300 cm −1 .Oxymercuration of compound A produces compound B, which has molecular formula C 8H 14O 2. Compound Balso has four peaks in its 13 C NMR spectrum, and its IR spectrum is characterized by strong bands at 1725 and2950 cm −1 . 1 H NMR spectrum of compound B shows a doublet at 1.11 ppm (integrating for 6H), a singlet at1.98 ppm (integrating for 6H), and a quartet at 2.74 ppm which integrates form 2H.. Based on this information,draw the structures of compounds A and B in the provided boxes, and show your reasoning.40 points9D O N O TW R I T EI N T H I SS P A C E

8. Order the three compounds A–C listed below by increasing acidity, and rationalize your answer usingresonance structures.30 points10D O N O TW R I T EI N T H I SS P A C E

APPENDICES1H NMR-OH-NH12 1110 9 8 7 6 5 4 3 2 1ppm0ROCOHOCR HH-C-XAr-H C=C-H H-C-OH-C-ArH-C-NH-C-SHCH 3CH 2CHX = an electronegative atomH-C-C=OH-C-C=C1H NMR CHARACTERISTIC CHEMICAL SHIFTS / ppmmethyl methylene methyneCH 3- -CH 2- CHotherRC0.9 1.4 1.5-OH1-5RC COCR1.6 2.3 2.62.1 2.4 2.5CC-NHCHHCAr-H1-32.55.57.3R NR-ArR BrR Cl2.2 2.5 2.92.3 2.7 3.02.7 3.3 4.13.1 3.4 4.1ROCROCHOH109-12RO3.3 3.4 3.7

APPENDICESINFRA-RED GROUP ABSORPTION FREQUENCIESTYPE OF VIBRATION FREQUENCY (cm -1 ) WAVELENGTH (µ) INTENSITY (1)C−H Alkanes (stretch) 3000-2850 3.33-3.51 s−CH 3 (bend) 1450 and 1375 6.90 and 7.27 m−CH 2 − (bend) 1465 6.83 mAlkenes (stretch) 3100-3000 3.23-3.33 m(bend) 1700-1000 5.88-10.0 sAromatics (stretch) 3150-3050 3.17-3.28 s(out-of-plane bend) 1000-700 10.0-14.3 sAlkyne (stretch) ca. 3300 ca.3.03 sAldehyde 2900-2800 3.45-3.57 w2800-2700 3.57-3.70 wC−C Alkane not usually usefulC=C Alkene 1680-1600 5.95-6.25 m-wAromatic 1600-1400 6.25-7.14 m-wC≡C Alkyne 2250-2100 4.44-4.76 m-wC=O Aldehyde 1740-1720 5.75-5.81 sKetone 1725-1705 5.80-5.87 sCarboxylic acid 1725-1700 5.80-5.88 sEster 1750-1730 5.71-5.78 sAmide 1700-1640 5.88-6.10 sAnhydride ca. 1810 ca. 5.52 sca. 1760 ca. 5.68 sAcyl chloride 1800 5.55 sC−O Alcohols, Ethers, Esters,Carboxylic acids 1300-1000 7.69-10.0 sO−H Alcohols, PhenolsFree 3650-3600 2.74-2.78 mH-Bonded 3400-3200 2.94-3.12 mCarboxylic acids (2) 3300-2500 3.03-4.00 mN−H Primary and secondary amines ca. 3500 ca. 2.86 mC≡N Nitriles 2260-2240 4.42-4.46 mN=O Nitro (R−NO 2 ) 1600-1500 6.25-6.67 s1400-1300 7.14-7.69 sC−X Fluoride 1400-1000 7.14-10.0 sChloride 800-600 12.5-16.7 sBromide, Iodide 16.7 s___________________________________________________________________________________(1) s = strong, m = medium and w = weak(2) note that the -OH absorption of solid carboxylic acids which run as a nujol mull can be difficult to see as they maybe very broad

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