Chem 317 S04 Page 1 of 7 Kantorowski Exam I 19 April 2004 Name: This exam contains 6 pages of questions confirm this once you begin The last page is a spectral data table that can be removed You will have 50 minutes No calculators or models are permitted Read all questions carefully answer the question that is asked! Illegible or indecipherable answers may not receive potential partial credit Good luck! 1. (9 pts) Name or draw the following compounds adhering to the rules of IUPAC nomenclature. a. 2-methyl-3-heptyne b. 1,5-cyclooctadiene c. (a) 2,2-dimethyl-3-hexyn-2-ol (b) 2-methyl-3-heptyn-2-ol (c) 2,2-dimethyl -3-heptyn-2-ol (d) 1,1-dimethyl-2-hexyn-1-ol 2. (7 pts) The typical chemical shift range for an alkenyl proton is 5 6 ppm. owever, the chemical shift values for the alkenyl protons in cyclopent-2-ene-1-one are 6.21 and 7.75 ppm. Clearly explain why both are farther downfield than the typical values and specifically why b is farther downfield from a. 6.21 ppm a 7.75 ppm b
Chem 317 S04 Page 2 Initials 3. (21 pts) Provide the structure of the major organic product or products expected from each of the following reactions. Write "NR" if no reaction. Indicate stereochemistry where applicable. Cl (excess) C 3 D - 65 C 1) NaN 2 2) 2, Pd/BaS 4 quinoline, Et K 200 C 1) Sia 2 B, TF 2) 2 2, Na, 2
Chem 317 S04 Page 3 Initials 4. (6 pts) Identify the major Diels-Alder product expected from the following components. Be sure to clearly indicate stereochemistry where appropriate. D C 6 6 5. (6 pts) n the lines provided, indicate which proton is associated with the given spin-spin coupling data. Proton J (z) 8.6, 3.3 a 17.4, 3.3 17.4, 8.6 c b 6. (9 pts) Provide the reagents that will accomplish the following chemical transformations. Two or more steps are required for all of these syntheses. Be sure to number steps (1, 2, etc.). 1. 2, hn
Chem 317 S04 Page 4 Initials 7. (18 pts) Clearly circle the correct answer for the following questions. There is only one correct answer for each; no credit will be given if more than one answer is circled for each question. a) Identify the most acidic compound from the following: N 3 b) Which of the following dienes will react fastest with nitroethene (C 2 =CN 2 )? C 3 c) What is the most commonly used NMR reference compound? CCl 3 (C 3 ) 4 Si (C 3 ) 2 S d) Which of the following compounds is the weakest acid? Cl e) Identify all diastereotopic hydrogens in (S)-2-bromopentane. a, b, and c b and c a d and e b, c, d, and e only a f) Which of the following represents an allene? e c d b 2 C C C 2 2 C C C C 2 2 C C C C g) Circle the most electron poor dienophile. I C 3 CN h) Which of the following compounds will have the highest boiling point? i) Which of the following dienes will produce the least amount of heat when subjected to catalytic hydrogenation?
Chem 317 S04 Page 5 Initials 8. (12 pts) Provide a structure in the box provided for the compound with a molecular formula of C 5 10 2 whose 1 NMR spectrum and 13 C NMR and IR data are given below. To receive partial credit you may draw reasonable, identified fragments of the compound in the smaller boxes. More advanced fragments will be given more credit than simpler fragments. Partially Assembled Fragments (note: there may be more boxes than actual fragments): Final Structure: 3, s 6, d 13 C NMR data: 175, 63, 34, 21 ppm The IR spectrum displays strong peaks at 1740, 1153 cm -1 1, m
Chem 317 S04 Page 6 Initials 9. (6 pts) Provide the diene and dienophile that were used to produce the following cycloadduct. + D Diene Dienophile 10. (6 pts) Provide a complete and detailed mechanism that accounts for the formation of 1-chloro-2- butene from 1,3-butadiene. Be sure to include all arrows, formal charges, and lone pairs to ensure full credit. Cl Cl Page Score Possible 1 16 2 21 3 21 4 18 5 12 6 12 Total 100 I II III IV V VI VII VIII Li Be B C N F e Ne Na K Mg Ca Al Si P S Se Cl Ar Kr I Xe
Chem 317 S04 Page 7 Initials C 2 11-13 ppm C C C X C X =, hal C C alkyl R- 1-5 ppm 11 10 9 8 7 6 5 4 3 2 1 0 ppm ketone aldehyde carboxy acid ester amide aromatic C=C C C C-Cl, C- C= C= C=C C- alkane 200 180 160 140 120 100 80 60 40 20 0 ppm Characteristic IR Absorption Values Functional Group Bond Stretching, cm Intensity Zone 1: 3700 3200 cm alcohol - 3650 3200 variable; usually broad alkyne C- ~3300 strong amine, amide N- 3500 3300 medium, often broad Zone 2: 3200 2700 cm alkane sp3 C- 2960 2850 variable aryl, vinyl sp2 C- 3100 3000 variable aldehyde sp2 C- ~2900, ~2700 medium, 2 bands carboxylic acid - 3000 2500 strong, broad Zone 3: 2300 2100 cm alkyne C C 2260 2100 variable nitrile C N 2260 2220 variable Zone 4: 1950-1650 cm aldehyde C= 1740 1720 strong amide C= 1690 1650 strong aryl ketone C= 1700 1680 strong carboxylic acid C= 1725 1700 strong ester C= 1750 1735 strong ketone C= 1750 1705 strong enone (C=C-C=) C= 1685 1665 strong aromatic overtones 1950 1750 3 or 4 small peaks Zone 5: 1680 1450 cm alkene C=C 1680 1620 variable aromatic C=C ~1600, 1500-1450 variable; 1600 often 2 bands Fingerprint region: < 1450 cm