Chem 342 Organic Chemistry II Final Exam 13 May 2009

Transcription

1 hem 342 rganic hemistry II Final Exam 13 May 2009 KEY Please read through each question carefully and answer in the spaces provided. A good strategy is to go through the test and answer all the questions you can do easily. Then go back and tackle the more difficult problems. Please make sure your structures are drawn clearly and indicate any stereochemistry with bold or dashed bonds. opyright ScienceartoonsPlus.com. Reprinted with permission. Finally, think about what you know. Reason and common sense can often help you out. Problem 1 Problem 2 Problem 3 Problem 4 Problem Problem 6 Problem 7 Problem 8 8 pts 8 pts 8 pts 10 pts 10 pts 10 pts 18 pts 18 pts Problem pts Problem pts Problem pts Problem pts Problem pts Problem 1 13 pts BUS 10 pts Problem 9 10 pts TTAL 200 pts hem 342 Final Exam page 1 Spring 2009

2 1. ircle all of the compounds below that are T aromatic. (8 pts) 2. ircle all of the following compounds that will give a tertiary alcohol product upon reaction with excess phenyl magnesium bromide (a Grignard reagent). (8 pts) 3. ircle all of the following compounds that will undergo electrophilic aromatic substitution faster than benzene. (8 pts) 3 4. Rank the following compounds in order of decreasing acidity with 1 being the most acidic and being the least acidic. (10 pts) 2 4 l 3 l 2. Rank the following compounds in order of decreasing basicity with 1 being the most basic and being the least basic. (10 pts) 1 2 Li Li ircle all of the following compounds that can undergo a self aldol condensation reactions. (10 pts) hem 342 Final Exam page 2 Spring 2009

3 7. For each of the reactions below choose the best set of reagents from the list below to carry out the reaction. (Place the letter of the reagents A, B, etc. in the box. ote that there are more reagents in the list than you need for the problem.) (18 pts) D l l F L 3 G possible reagents A. DIBAL- then 3 + B. KMn 4. 2, Fe 3 D. a, heat E. ( 3 ) 2 uli F. a, heat G. P., heat I. 2 2 J. mpba K. 2, Pd/ L. 3 Mg then Provide the major organic product for each of the following reactions. Indicate proper stereochemistry where appropriate. (18 pts) BS peroxides 3 l All 3 3 heat Snl l K( 3 ) 3 1,4 product hem 342 Final Exam page 3 Spring 2009

4 9. ircle the compound which best matches the following proton and carbon MR data. (10 pts) 10. For each of the following molecules, indicate the number of different proton and carbon resonances you would observe in the MR spectrum. (12 pts) # of 1 signals # of 13 signals # of 1 signals # of 13 signals hem 342 Final Exam page 4 Spring 2009

5 11. Provide the major organic product for each of the following reactions. Indicate proper stereochemistry where appropriate. (18 pts) mpba 1) Tos-l, pyr 2) Sa S r P 3 I I 3 Mg then Provide the major organic product for each of the following reactions. (18 pts) 2 2 LiAl 4 then P 3 2 then 3 + l a 2 ab 3 Sl 2 l hem 342 Final Exam page Spring 2009

6 13. Provide the missing structures in the following synthetic sequence. Do not worry about showing stereochemistry. (21 pts) Et Et aet Et Et aet Et Et 3 + eat uli then pyridine ab 4 then 3 + P Provide the major organic product for each of the following reactions. (18 pts) 2 A cat. B 3 then excess 3 3 1) LDA 2) 3 2 A cat. 1) 2) LiAl 4 3) 3 + then 3 + hem 342 Final Exam page 6 Spring 2009

7 1. Friedel-rafts alkylation reactions are directed by substituents on the aromatic ring. Shown below is the electrophilic aromatic substitution of anisole with t-butyl chloride. ircle the major product of this reaction. The mechanism involves a cationic intermediate. omplete the structures in the box for the intermediate in the reaction for the attack of the electrophile in the meta position. Show the location of the t-butyl group as well as all double bonds and charges for the resulting three resonance structures. (13 pts) 3 l All ircle the major product anisole Draw addition of the electrophile to the meta position BUS QUESTIS: What is the name of the following essential amino acid? ( pts) 2 phenylalanine iefly explain the following terms that we use describe protein structure: ( pts) Primary Structure: amino acid sequence Secondary Structure: Tertiary Structure: structural domains within the protein such as loops, beta sheets and alpha helices overall 3-dimensional shape of the protein - e.g. globular proteins Quaternary Structure: structure of multiple protein complexes hem 342 Final Exam page 7 Spring 2009

8 Typical MR hemical Shifts Functional Group Type 1 hemical Shift (ppm) 13 hemical Shift (ppm) Alkane Allylic or next to carbonyl X next to halogen or alcohol next to oxygen of an ester vinylic aromatic X aldehyde alcohol carbonyl of ester, amide, or carboxylic acid (X =, ) varies widely will exchange with D 2 /A /A carbonyl of ketone or aldehyde /A hem 342 Final Exam page 8 Spring 2009