Final Exam April 30, 2014

Transcription

1 Bennett Department of Chemistry Chemistry 234 Final Exam April 30, 2014 ame: This exam is a closed book, closed notes. Calculators and a molecular model set are allowed. You must show your work in order to receive partial credited. Question I (30 points): Question II (85 points): Question III (32 points): Question IV (12 points): Question V (28 points): Question VI (22 points): Total (out of 209) : 1

2 Question I. Multiple Choice (select the E most likely answer, 1.5 pt each) Please give the pka of the MST ACIDIC proton in each molecule. 1) 2 C 3 3 C C C 3 2 A) 12 B) 20 C) 35 D) 40 E) 45 2) 6) The ΔG for the given reaction. A) 5 B) 10 C) 12 D) 20 E) 45 3) A) 5 B) 10 C) 16 D) 25 E) 35 4) A) 10 B) 16 C) 20 D) 40 E) 45 5) A) 5 B) 10 C) 20 D) 40 E) 25 Ph K C + Bu 3 2 Li + ΔG: A) 20; B) 14; C) -6.8; D) -34; E) -26 Circle the right term to describe the following molecules. 7) 8) A) Aromatic; A) Aromatic; B) Anti-aromatic; B) Anti-aromatic; C) on-aromatic C) on-aromatic ow many different s will shown on MR for the following molecule 9) A) 4; B) 5; C) 6; D) 7; E) 8 What is the most likely chemical shift for the aldehyde C- in 1 MR. 10) A: 1.0; B: 1.5; C: 4.0; D: 5.5, E: 10 What is the most likely chemical shift for the C 3 C 3 in 1 MR. 11) A: 1.0; B: 1.5; C: 4.0; D: 5.5, E: 10 What is the most likely chemical shift for the C 3 C 3 in 1 MR. 12) A: 1.0; B: 1.5; C: 4.0; D: 5.5, E: 10 What is the most likely IR C- stretching for the C 3 C 3 (cm -1 ) 13) A: 3050; B: 2900; C: 2200; D: 1700, E:

3 14) Rank the stability of the most stable radicals formed from the following molecules Select the most stable compound/particle in the following group. A) 1>3>2>4>5 B) 2>1>3>5>4 C) 3>2>4>5>1 D) 4>3>2>1>5 E) 1>4>3>2>5 15) a) b) c) 16) a) b) c) d) 17) a) b) c) d) e) 18) Which one of the following statement was T true for normal Diel-Alder reaction? A) [4+2]; B) Stereo specific; C) Edo favored; D) endothermic 19) More substituted radicals are more stable than less substituted radical. A) Resonance effect; B) Inductive effect; C) S factor; D) yperconjugation; E) ctet Rule 20) Reactivity difference between nitro-benzene and benzene was mostly driven by A) Resonance effect; B) Inductive effect; C) S factor; D) yperconjugation; E) ctet Rule Question II. Reaction (3 pts each except A and B, 85 pts total) A) Provide the products in each block (2 points each, 18 points total) Br ac 1) LA; 2) 2 C 3 CCl, Pyridine 1) a, heat 2) 2 A 1) LA; 2) 2 A DCC SCl 2 KMn 4 KMn 4 (C 3 ) 2 CuLi KMn 4 3

4 B) Provide the products in each block (2 points each, 22 points total) Br 2, 3 + aac Cl, 2 ac 2 S 4, heat mcpba Pd/C 2 1) a, heat 2) 2 1) PhLi 2) 2 1) 2) Cl, 2 SCl 2 C) Provide the products or reaction conditions for each question (3 points each, 45 points total) 1) excess C 3 I; 2 2) Ag 2 ; 3) heat C 1) SCl 2 2) pyridine 2 2 1) PhLi (excess) 2) Cl - + 4

5 Me + AlCl 3 1) Me 2 CuLi 2) PhLi 3) PBr 3 3, 2 S 4 Me 1) MeLi (Excess) 2) 2 3) SCl 2 4) Mg 5) C 2 6) 2 S 2 Br 2 1) - ; 2) 2 C=; 3) Cl + C 3 C 3 1) C 3 MgBr (excess) 2) Cl, C 3 5

6 Δ + a Me Question III. Mechanism. (32 points total) + 2 Δ trace acid (4 pts) 6

7 Example of Wolff-Kishner reaction and detailed electron-pushing mechanism. (4 pts) + C 2 = Cl (4 pts) Me + Ph Cl heat (4 pts) 7

8 Example of Wittig reaction and detailed electron-pushing mechanism. (4 pts) Draw the products of the following reactions. ote, it is same starting material under different conditions. Explain why. (4 pts) 25 o C aet, Et -78 o C LDA, TF Br A B CMe Δ MeC CMe CMe label the stereochemistry of the product (4 pts) 8

9 Chemistry 234 3C Spring Ph DABC (4 pts) Question IV. MR and structure analysis (12 points total) A) MW= 110, (4 pts) 9

10 Chemistry 234 Spring 2014 B) MW= 104 (4 pts) C) MW = 135, (4 pts) 10

11 Chemistry 234 Spring 2014 Question V. Synthesis (28 points total) A) Synthesis of the following molecules from benzene and other necessary reagents (4 pts each, 12 pts total) Br 11

12 2 B) Synthesis of the following molecule from the given starting material and any necessary reagents (4 pts) Cl Cl C) Synthesis of the following molecule from starting materials with 5 carbons or less and any inorganic reagents (4 pts) C 3 12

13 D) (4 pts) 2 E) (4 pts) Question VI. Assay questions (22 points total) A) Draw the chemical structures of 20 amino acids (5 points total) 13

14 B) Draw the A-T and G-C base pairs (4 points total) C) Draw the chemical structures (6 points total) Aziridine PCC DCC Malonic acid porphyrine DIBAL D) Draw the corresponding orbitals of the following cation (3 pts) E) Explain CSY, ESY, MQC, MBC (1 pt each, 4 pts total) The end! 14