chem3b-fall02-mt1-unknown-soln

chem3b-fall02-mt1-unknown-soln - Chemistry 3B, Midterm 1...

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Unformatted text preview: Chemistry 3B, Midterm 1 Tuesday, October 8, 2002 Studentname: W Student signature: Write TA’s name or Lecture Only: 1. Please make sure that the exam has 9 pages includingithis one. 2. Please write your answers in the spaces provided. 3. Write clearly; illegible or ambiguous answers will be considered incorrect. 4. Only writing implements are allowed (No Calculators). GOOD LUCK! 1. 8 points 2. 30 points 3. 50 points 4. 37 points 5. 35 points 6. 20 points Total 180 points MINI-PERIODIC TABLE 1. Provide structures for the following chemical names (8 points) «do» m-chlorobenzoic acid QM benzyl chloride CH3 (\ [MD H r it 2-chloro-3-flourotoluene 3’4'dimEthOXYbenza'dEhl/de 2. Answer the following questions. Every wrong answer cancels a correct answer (30 points). (a). Rank the compounds according to those that would react most rapidly with Brz, FeBr3 to those that would react the least rapidly [l = most rapid, 5 = least rapid] (6 points). C “$355 512%; (b). Circle the compounds that are aromatic (6 points). .ma (c). Circle the compounds that are anti-aromatic (6 points). HEN: E @ (d). Rank the dienes according to those that would undergo a Diels Alder from most to least rapidly [l = most rapid, 5 = least rapid] (6 points). :QCCEQ \ 251L+3 (e). Upon treatment with methanol. each of the following compounds produces methyl ether products with the rate-determining step being formation of a carbocation intermediate. Rank the compounds from 1 to 5 for rate of reaction [1 = fastest rate, 5 = slowest rate] (6 points). '+52 3‘11 3. For each of the following reactions supply the missing reagents or major organic product in the space provided. If no reaction is expected indicate by NR. (50 points total). OH - (a) U A v H3PO4 1. NBS, hv, 0014 MC (b) 2. MeOH, A (d) (h) CH3 No2 H20 —> (under kinetic control, i.e., low temp) H20 (under thermodynamic control, i.e., high temp) 1. Clz, FeCI3 2. Fe, HCI "3 N02 (‘1'. 35 points total. (a) Show an energy level diagram for the molecular orbitals of the tropylium anion drawn below (10 points). 0.9 (b) Place the electrons in the appropriate molecular orbitals. Does the electron placement establish the molecule as aromatic or antiaromatic? Briefly explain (one sentence is all that is necessary) (5 points). hnlirovm’lic. Two WM «9 an firm? (c) Show an energy level diagram for the molecular orbitals of the cyclopentadienyl anion drawn below QED (10 points). (d) Place the electrons in the appropriate molecular orbitals. Does the electron placement establish the molecule as aromatic or antiaromatic? Briefly explain (one sentence is all that is necessary) (5 points). AWVYld’ltc. No unfaird 2Q (e) The compound below has a rather large dipole moment. Indicate what you think that that dipole moment might be (with an arrow, NOT a number) and give a brief explanation. Hint: draw resonance structures (7 points). 9 4.7 .. <4 4e C343 . . . . \flmr B in lwm ammo awl W: andl‘lmtmqlwm fl filial)on \ (aiim 0K wiring/Wm mile» N4 )’ (Kmymvde/l thWVi qR fitmm {mm Hg Emle 9......9—9 \2 g. (3) Provide detailed mechanisms for the following transformations (35 points). AICI3 20 points CI . DCl (b) 15pomts M MD + OMB <3 {'9' q MD’Q‘fi/Efik/Daw $ : MD “‘9 (MD .9 ' \z :( 9 'a 6. Provide the most efficient synthesis. You may employ any reagents of your choice (20 points). Br m Q Rdro {35 Br 9 fix fies/GEL :> Chemistry SB, Practice Midterm 1 Tuesday, October 1, 2002 Student name: 3W{ Student signature: Write TA’s name or Lecture Only: 1. Please write your answers in the spaces provided. 3. Write clearly; illegible or ambiguous answers will be considered incorrect. 4‘ Only writing implements are allowed (No Calculators). GOOD LUCK! 1. 10 points 2. 30 points 3. 55 points 4. 30 points 5. 35 points 6. 20 points Total 180 points MINI-PERIODIC TABLE 1. Provide structures for the following chemical names (10 points) '— NHL Nfi 0 o z n Cl 2,3-dichloroaniline o-aminobenzoic acid 0H 2-phenylethanol 2,5-difluorophenol Br 0 N-bromosuccinimide (NBS) 2. Answer the following questions. Every wrong answer cancels a correct answer (30 points total). ( . Circle the TC systems that have five molecular orbitals (6 points). (a .. \ .. @@ M a) (b). Circle the compounds that are aromatic (6 points). 0.6 oooo planar planar Planar (c). Circle the compounds that are anti-aromatic (6 points). (d). Rank the compounds according to those that would react most rapidly with Brz, FeBr3 to those that would react the least rapidly [l I most rapid, 5 : least rapid] (6 points). 5 N02 2: Haoaa ammo-o (e). Rank the following cations from most stable to least stable [I 2 most stable, 5 : least stable] (6 points). 5 3 _ 2 2@ /\® Meg W69 \A-beg 2. For each of the following reactions supply the missing reagents or major organic product in the space provided. If no reaction is expected indicate by NR. (50 points total). Oink A MC (8) ____. Me 1. HCI O 2. H20, A N02 o + N02 Br Br C§ CH30H20H Br (6) \0/ (under kinetic control, i.e., low temp) CH CH OH Br 3 2 0v (d) (under thermodynamic, control, i.e., high temp) m :1 I —-——> 'H H / CHO / CHO A (h) + J _______. f \ ’1]; Me 0M9 1. CI2, FeCi3 Q (i) 2. H30+, A SO3H © 1' A ,H3PO4 2. HNOg1 H2304 A (k) __‘—’ 3. 30 points total. (a) Show an energy level diagram for the molecular orbitals of the cyclopropenyl anion drawn below (10 points). (b) Place the electrons in the appropriate molecular orbitals. Does the electron placement establish that the molecule as aromatic or antiaromatic. Briefly explain your answer (5 points). MAW}. We (my/l lMs Unfaitch clcdrbns in amlbowfll'mj orbitals. (c) Show the energy level diagram for the molecular orbitals for allyl anion (10 points). ((1) Place the electrons in the appropriate molecular orbitals. Is allyl anion more stable or less stable than cyclopropenyl anion? Briefly explain your answer (5 points). M012 stable. AM who his \np WM ‘29 with in: Cyclorwlxnyl 4:30)!) MUM. Union has 2&9 Iv) nonhMlm] mural) JM )1 No New WWW 099ml. 4. Provide a detailed mechanism for the following transformations (35 points). (a) Provide all of the monobromination products for this transformation. Note: Because NBS is solely used to generate low concentrations of Bl‘z you may simply use Brz in your reaction mechanism (20 points). 6 NBS, hv, CCI4 Bil/gr ~923r' at“; 'N rim 6r #6 r.) rel “ B 13" 5/ P H (4N (b) (15 points). 5. Provide the most efficient synthesis. You may employ any reagents of your choice (20 points). R HG .gr HZN N113: fl 0 IEI'uEeI'ni313:5,f EB, Extra Practice thlems 2. For each nfthe tulle-wing mtlnns supply lhe missing reagents cur main-1' organs: pmducn in the Space pmvidud- ll'ncl median is flffltfli indium: 333' HR- Moire.” iii EEGH . ' ’— 3. HEHHJHHJ Lm aims HD 1. ulna; H {b} m 2. I'u'leLi [:5]: DH 3. Eq. markup 1- :33 _ 0 2.1.1, AcflH EMU“ {=1 H] {a} {fi 2 [HI The nmlmulm drawn belnw are: key building blacks in 1h: :i}'1'ltl'll."2-iiH urn-lam}r Wychnmi'm drugs. CimM ll'lr: campaund that wnuld haw, Illa: large-fl K.“ flit-1‘ I'Iyiralt film-Julian. Pruride a brief uplantinl inf :r'nur answer. Cl (5 L I Ph _ I RESBWWC SJHHJMW 0f Tim {[[r‘wl 51mg jut: L5 mmnhr‘rrzd Jde’Ta 1151C IMMUNE. E‘HHT WHT fESUhfl 4mm Fahmw‘y [MQA hfirfijf‘fl. {bj Circle mmpuund belnw that wnuld 111m: [11: Iflrflflfil‘ Keg f'ar hydrate fgm'latinu. Pmlde a brkf uphiatinl for your insurer. fgffi fly” w (L mm: ‘m Wm}? SUEWHH bmtn'flab’k hw rm! . mm: hm: Lawnafmmuq “up fine: l'fflfid‘r’i'ifi STWIES‘MMJH {WM WW“ r ’r‘m: mflei WWPGWJ '5 mwmmri’fJ Ada “re: 1]? {‘3 wmi‘nalnww} mqu 5:“ H". I Th1 Maj]?- .'!|-. Thu: finllmln'ng reactim is 3 km}: step in a mnuncrcial mutt: tu prustaglandiu derivatives. Prm'ide a muchanlsm. H D 1 H I H H Hang?” 20 + c=<_>=r:r Kg. Iii}! _ [51 L E'fi '3? m {1“ "it In H hi H H? H 5‘ 1.“ '1 D“ m g “a at; f1; W J”? M [LE g3] 123 \P A H e— fig? “3" [:1 NEPD‘ ahfln’j {T ...
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This note was uploaded on 07/05/2010 for the course CHEM N/A taught by Professor Head-gordon during the Fall '09 term at University of California, Berkeley.

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chem3b-fall02-mt1-unknown-soln - Chemistry 3B, Midterm 1...

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