Chemistry 3A - Spring 2000 - Frechet - Midterm 3

Chemistry 3A - Spring 2000 - Frechet - Midterm 3 -...

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Unformatted text preview: Chemistry sit - spring sees Mldtarrn 3 Professor Jean Freshet Vour full signature; April 11". Elli": Print your l'ull name_ that me. First nun. week] Your SID Please sheet: the seeiien number and name er your GSLI'TA. _1E1 VerdugoJJawn _361 Hamanfiristina __'i F1 Hopp.Jphn ' . _3?1 Heohtfitetan _1Ei1 Borthsflhristdpher _3‘11 $axon.Eliana _1Ei:l Fujdalaflyrle _321 Cooltfirian __111 Watltinsfiregonr _Jltlt PurdtrJulatthew ___121 Btaokwellflelhanyr _ T1 E'rarisuohn _131 Foxfianiel _Il11 HellendAHdFew _1-i1-1 Werker'naEuan _F_1121 Duncanfind'rew _se1 Peterltaflaroy _=ist Trh‘bleflexander ____2T1 Lee.Charles _511 Marsaurelle,L'rss _211 Tripp..lenniier £521 .len.li'li'iend1ir ___221 Fadillaflrnatrra _531 Ling.Fran+I: if you are rnaldng up an I-grade. indicate the semester you tool: 3A and the Professor Do- Hetwrite in this sea. This exam has to pages; make sure that you have them all. We will and.r grade answers that are it the designated spades. Please do your ssratel-i well: on the basics ofthe exam pages. Write only 5mg answer to H {14} 1- a. r {14] 3. a {11} 4- sash problem: mulliple answers wlll remiss flared“, -' 1'- {12} Evan if one of them is eerreot. gifig} E. I fl H m This examination runs for a total at so minutes. T 3 :1 a: No questions will be answered by preottss after the ' _' exam begins. Please write legible; ambiguous or E'—[123 messyr answers will reeeiee m Totalfllil so} A partial periodic table and data needed for calculations oan be found on page 1E ofthe exam. Ifi'Elfllilil J.M..l. Fl'lrcl'l-Il. Berkeley. GA Chem. 3A Midterm Exam #3 Page 2 of 10 1. (14 points) (a) Draw the 1H-NMR spectrum of CH3CHZCHZCI. In your drawing, show the appropriate location of the peaks (chemical shifts) as well as the splitting (assume that "ideal" spilling occurs). Each peak, or set of peaks, should be labeled to indicate which part of the molecule it corresponds to. Also show the peak integration as a "step" drawing. ‘ WNWMWJ; My J ‘ w A mw_mwe ‘ m “Wm-MNNM‘...W« + 6 Nam s 4 3 2 a, 5' 20 (b) How many signals would be present in the "normal" (proton decoupled) 13C NMR spectrum of CH3CH2CH(CH2CH3)2 ‘ l l H, 7 1w? Answer: K , i (M CHZf—H - ant/CH3 ' (C) Give the major product(s) of each of the following reactions. (\BM I 05 H2 DH Z M Hy ——-—> M p 0 ,/ t 0 H h Br Chem. 3A 2. (14 points) (a) Reaction of 2-bromo-2,3-dimethylbutane with strong base leads to elimination to form two isomeric alkenes A and B. Show the structure of each of these two alkenes and indicate how many peaks will be found in the 1BC NMR spectra of each. (b) Which reagent (used in class) would be best to produce the highest yield of the alkene with the greatest number of peaks in its 13C NMR spectrum (be specific). Midterm Exam #3 Page 3 of 10 H3C Br 932m"??? base J Hscflcm —-—-> A+B ' 3 (0) Name the following according to IUPAC nomenclature. Specify absolute stereochem where appropriate. istry his??? Z'brorwo’ l” c) o HOCHZCH(CHZCH2(3H3)2 c, airbag-fir um? , l Ur O C C: 1% ‘ l C ELL“? (“3' E C lorfl Oklmfkv Chem. 3A Midterm Exam #3 Page 4 of 10 3. (11 points) (a) The chemical shifts for the "normal" (proton-decoupled) NMR spectrum of 3-bromo-1-chloro- 2,2-dimethyl butane are given below. Sketch the DEPT-135 spectrum for this molecule. (b (CL‘ .r" ) (a) 50 ppm CH3 B (b) 15 ppm ‘x‘ l / ' Ae, (c) 45 ppm Cl—CHz-C—CH\* "’7‘ (d) 40 ppm ,1 I \ CH3 (9) 25 ppm I,” CH3 \\ X ’4 \\ (a) (d) Label each peak (a), (b), etc... on the spectrum to identify them 0)) (b) Write a clear structure (Fischer projection) for mesa-1,2,3,4-butanetetraol 0% ch .« a i .1 ,c z C} r"? C? I i ‘ -: C ti 6 ll Cu 2 aw _______________________ WW Chem. 3A Midterm Exam #3 Page 5 of 10 4. (12 points). (a) write a clear structure (Fischer projection) for (R)-2—pentano| 0H. t, c Li 3c M c M H2 1) Mg, ether CHaCHZCHzCl “a c I: W: d O 3) H+ / HzO 1) Cro3 sto4 H20 CHscHzCHz-CIZH —"_——> OH 2) LiAID4 in ether 3) H+ / H20 t (J! §:I(L§S_zfi~ “a b O 1) (CH3)ZCHMgCI in ether —-————-———————> 2) H+ / H20 Chem. 3A Midterm Exam #3 Page 6 of 10 5. (13 points) (a) Show a step-by-step mechanism (with all curved arrows) for the reaction below: HCI Oil. *" QC *4 +L ,7 .. r a, Qfiflw > 4.9 FT/g/ t Hfo’ 2% ._ § '6 ' “Law! ‘C\ '“3 Gay" (SN i) Lh/ (b) Complete the reactions below showing all the missing reagents (and key solvents if appropriate). In all cases the choice of reagent must be such that the product shown is the major product of the reaction. CH3 H (, Hz 3: 01f 1- Citgctbopk ‘ Chem. 3A Midterm Exam #3 Page 7 of 10 6. (14 points) (a) show a step by step synthesis ofO—D from < ' All reagents and also solvents, if appropriate, must be shown. Q- 324:“ Q. at Q» \ '\ “M l . Dz ’ t \_ OH (b) propose a synthesis of (CH3)2CH+CHZCH3 from CH3CHZCH3 and CH30H3 CH3 you must show all steps and include an reagents and solvents as appropriate. ..\\\ Chem. 3A Midterm Exam #3 Page 8 of 10 O A/ T from 1-bromopropane and 2-bromopropane 7- (10 POiNts) (a) propose a synthesis of Show all steps, reagents, and solvents used. CrO3 CH3CH2CH2CH20H T» H /H20 036mm H2O2 (excess) CH3CHZSCHZCH3 ————> W catalyst f/V MWK‘ ‘ CH3CH2CH2l —-—-—-———-————> / /’ // CH3CH2éCHZCH3 Chem. 3A Midterm Exam #3 Page 9 of 10 8. (12 points) Chem. 3A Midterm Exam #3 Page 10 of 10 Note: There are no questions to be answered on this page, it only contains data that may be of use in solving the questions contained in this exam. Not all of the data given is needed. Value of gas constant: R = 2.0 cal deg'1 mol'1 Value of 6 (base for natural logarithms) e = 2.718 Value of absolute zero (kelvin) = -273°C Partial eriodic table of the elements 0 1A 2 1.00794 IIA 1O 3- 4 LI Be 6.941 9.01218 11 12 Na M9 22.9898 24.3050 19 20 K Ca 39.0983 40.078‘ 7 38 Rb Sr 85 678 87.62 5 6 3 .4 5 5 Cs Ba 132.905 137.327 S 30 9738 3 . 6 6i; 2% (3% die As e Br Rr 63.546 65.39 69.723 72.61 74.9216 78.96 79.904 83.80 , 47 48 53 49 $50 , $2, , I, , In 11 e 19%; $132,011 114.82 110.710 121.75 127.60 125.904 79 80 8 85 86 Au H Tl 133: $31 133 At Rn 196.967 200.59 204.383 207.2 208.980 (209) (210) (222) ! ...
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This note was uploaded on 03/12/2009 for the course CHEM 3A taught by Professor Fretchet during the Spring '08 term at University of California, Berkeley.

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Chemistry 3A - Spring 2000 - Frechet - Midterm 3 -...

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