Exam2 - kfiiPRINT NAME 1X. (10 points) The (1R)~enantiomer...

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Unformatted text preview: kfiiPRINT NAME 1X. (10 points) The (1R)~enantiomer of camphor (one of the isomers is shown below) has a rotation of +44°. A) Draw the (lR)- and (lS)—enantiomers using the structure fragments provided. b fi %/0 G g ‘0 or :3 A. ( l .S’)—camphor (lR)—camphor +2— +2, - B) ' You have a camphor sample with a specific rotation of —1 1°. 1) What is the optical purity of the sample? Please show calculation. n/p, x lOOZ The sample has an optical purity of g%. .4. 3 2) What is the composition of the sample? Please show calculation. 252, 5 + 7572,25 75/LZR The sample consists of 5 % R and . % s_ _ 4" 3 t——I WW») 307/315 EXAM II DRAFT FALL 2010 4 PRINT NAME IY. (10 points) The (lS)~enantiomer of camphor (one of the isomers is shown below) has a rotation of —44°. A) Draw the V(lR)— and (lS)—enantiomers using the structure fragments provided. (1R)—camphor (lS)—camphor ’1’? . p ’i" er- ‘L B) You have a camphor sample with a specific rotation of +33°. 1) What is the optical purity of the sample? Please show calculation. 53/trLr x (002, The sample has an optical purity of 7 S %.x ‘7“ 3 2) What is the composition of the sample? Please Show calculation. Zg/zzs +3 {a cm H») 307/315 EXAM II DRAFT FALL 2010 a 5 PRINT NAME (12 points) The solvolysis of (2R)—2—bromohexane in methanol results in a reaction mixture containing two products. 2X. a) Draw the starting material and the products (indicating the absolute configurations) : Br EV QCHZ, +13 w Product (2R) M 2"/ Product (23) Starting Material absolute configuration b) Write a complete mechanism for the conversion of the starting material to one of the products and indicate the rate determining step. Use curved arrows in the usual way, indicate with the appropriate symbols whether reactions are reversible, and show all lone pairs and . charges. Do 11;) Reaction Coordinate 307/315 EXAM II DRAFT FALL 2010 PRINT NAME 2Y. (12 points) The solvolysis of (2S)~2—chlorohexane in methanol results in a reaction mixture containing two products. a) Draw the starting material and the products (indicating the absolute configurations) 9} 9C”; OCH; /\/\/ /W ’t‘" a»! t~f Starting Material Product I Product absolute configuration . (25) (2 R) b) Write a complete mechanism for the conversion of the starting material to one of the products and indicate the rate determining step. Use curved arrows in the usual way, indicate with the appropriate symbols Whether reactions are reversible, and show all lone pairs and harges. Do not Show C—H bonds. ’ i M‘ Mg?” .7 a I ’a fig“ tarfleptt"‘f”jfif WM ‘ _ *6, i J A "Mr-"M " MW + :Cl; Mp; arm/\N -— H ‘ V 5.: + E ow HC c)3Draw a reaction coordinate diagram describing the conversion. Reaction Coordinate 1 307/315 EXAM IIDRAFI‘ 1 FALL 2010 7 l l PRINT-NAME 3X. (10 points) The free-radical chlorination of (R)—2—methylthiobutane gives rise to several monochlorination products. ‘ Using the templates and blanks below, draw the structures, using wedges and dashed lines as necessary, of all monochlorination products that are formed by chlorination at C—1 and C3. For each structure indicate the number (1, 2, or 3) of each chiral carbon and the the absolute configuration of this carbon. There may be more templates and more blanks than you need. SCH3 09b soH3 A/ Mfiok k/ Chiral carbons Chiral carbgrls - Chiral carbm Number Abs. Conf. Number: Abs. Conf. Number: Abs. Conf. 2.32? 2R 3, E: E? jig/ fl SCH3 Chiral carbons Chiral carbons Chiral carbons Number Abs. Conf. Number: Abs. Conf. Number: Abs. Conf. Indicate which, if any, products form in equal amounts. N O vi. I 307/315 EXAM IIDRAPT FALL 2010 8 PRlNT NAME (10 points) The free—radical chlorination of (S)~2—methylthiobutane gives rise to several monochlorination products. 3Y. Using the templates and blanks below, draw the structures, using wedges and dashed lines as necessary, of all monochlorination products that are formed by chlorination at C—1 and C3. For each structure indicate the number (1, 2, or 3) of each chiral carbon and the the absolute configuration of this carbon. There may be more templates and more blanks than you need. §CH3 §CH3 §CH3 Cl W Chiral carbons él Abs. Conf. ,' (Xi‘\ :- \ , Chiral 'carbons x“ Chiral carbons Number Abs. Conf. R ’L Number: Abs. Conf. _ii_w _§i __E:rg law» Numb er: 2 f [Wm/A 2. :3 §CH3 §CH3 Chiral carbons Chiral carbons Chiral carbons Number Abs. Conf. Number: Abs. Conf. Number: Abs. Conf. Indicate which, if any, products form in equal amounts. N 0 [t ‘ 307/315 EXAM II DRAFT - FALLZOIO 9 [id/xii {xfllafjgé ‘ PRINT NAME 4X. (14 points) Acetamide (shown below) is a Bronsted acid and a Bronsted base. In each of the parts below show all lone pairs and charges and do not show OH bonds. A) Draw the two most important contributing structures of its conjugate acid formed by protonation at the C=O group. ' CN C) Starting fiom a cycloalkane, propose a synthesis of . You may use any reagents and common solvents you wish. Use as many reaction steps as necessary. Put reagents above the arrow and any solvent below the arrow. Once you write the structure of a compound you can designate it with a roman numeral (1, II ...) and then use the numeral instead of writing the structure again. It saves you time and is easier for the grader (confused graders are less likely to give partial credit © ) is (7%“ a?” ' .... O“ m *3 ° CT I, fifng W say 307/315 EXAM 1] DRAFT FALL 2010 10 PRINT NAME 4Y. (14 points) CN v W A) Starting from a cycloalkane, propose a synthesis of . You may use any ‘ reagents and common solvents you wish. Use as many reaction steps as necessary. Put (f reagents above the arrow and any solvent below the arrow. Once you write the structure of a compound you can designate it with a roman numeral (I, ll ...) and then use the numeral instead of writing the structure again. It saves you time and is easier for the grader (confused graders are less likely to give partial credit @) or Cl; /hY‘ Brz/kv' Br 0"" C5 \« NJCN" ' I C 25ml 0 N W 0°?” B. Acetamide (shown below) is a Bronsted acid and a Bronsted base. In each of the parts below show all lone pairs and charges and do not show C—H bonds. Draw the two most important contributing structures of its conjugate base. C. Draw the two most important contributing structures of its conjugate acid formed by protonation at the C=O group. - 1: :~;v.».i~zcz::-.r.-;:~r 307/315 EXAM II DRAFT FALLZOlO ll PRINT NAME 5X. (15 points) A) Using as many of the templates as needed fill in the correct stereochemical representations of the major products of the following reactions (choose the most stable conformation). Write “no major produc ” if the reaction does not proceed. ~ other + Ot—Bu" WW” gig/Zn 'L...» {H W 307/315 EXAM II DRAFT FALLZOIO 12 PRINT NAME B) Consider possible E2 reactions of the molecule shown. Draw two Newman projections that illustrate the formation of alkenes (place the chlorine~bearing carbon up front). Place the resulting alkenes in the boxes on the right. Circle the major product. t-Bu Azk 'K OC(CH3)3 ‘ . ~——-—-———-——-———-—> H\ Irv ‘ H “a /H ‘ Cl, >K ‘ “\ /% H Cl Q wewmimosa;a,wfiamwwfimmns fi‘fiwkiflffie fi‘liffit’urfiFl-uj!Wwétlfirfi 7I‘IW Mwmwmarms«mmrm'w-a'xvvawmms:sa1amxvmazeynwzumime»vamutt Hm: 307/315 EXAM II DRAFT FALL 2010 13 5Y. (15 points) PRINT NAME A) Consider possible E2 reactions 0f the molecule shown. Draw two Newman proj ecti’ons that illustrate the formation of alkenes (place the chlorine-bearing carbon up front). Place the resulting alkenes in the boxes on the right. Circle the major product. L—Bu ' K OC(CH3)3 307/315 EXAM II DRAFT FALL 2010 14 I PRINT NAME B) Using as many of the templates as needed fill in the correct stereochemical representations of the major products of the following reactions (choose the most stable conformation). Write “no major produc ” if the reaction does not proceed. 307/315 EXAM ,II DRAFT . FALL 2010 , 15 PRINT NAME 6X (12 points) Of the many cyclic isomers of C4H6 BrCl five are achiral and there are nine pairs of enantiomers. Draw four cyclic chiral isomers in the boxes on the left and four cyclic achiral isomers in the boxes on the right, using dashed line—wedge projections. Only one member of an enantiomeric pair may be used. ’ Chiral C4H5 BrCl isomers Achiral C4H5 BIC] isomers {vswmwdmvuvaa mu- vu-«4115uixzwm i::~ v 307/315 EXAM II DRAFT FALL 2010 16 PRINT NAME 6Y. (12 points) Of the many cyclic isomers of C4H6 BrCl five are achiral and there are nine pairs of enantiomers. Draw four cyclic achiral isomers in the boxes on the left and four cyclic chiral isomers in the boxes on the right, using dashed line—wedge projections. Only one member of an' enantiomeric pair may be used. ' V I Achiral C4H6 BrCl isomers Chiral C4H6 BIC] isomers 307/315 EXAM H DRAFT FALLZOlO l7 Br Br Br Cl "4", [7' \d [j u r I .3: 5 Cl Achiral % 0+1ch CHzcl > Br r Chiral [j > I k c; plus enanllomer plus enantlomer CHZCI Cl Br r r ' H Gil-lac 3 plus enantlolner plus enantlomer plus enantiomer l Cl HzBr HgBr Br ' Cl plus enantlomer Plus enanfiomer H 05 plus enantlomer Cl Cl 3 k . 3430\b. CiBrHC\b 5 - 33'. :5 Br Br H30 plus enantlomer plus enantlomer two enantlomers Cl 6 Br Br Br\b H3C\b CE$ H3C\> g C! I H30 Er H3O plus anantlomer plus enantlomer Plus enanflO-mer plus enanfiomer PR1NT NAME 7X. (11 points) The 1H spectrum of a compound (C5H10C12O) has five peaks. Using the chemical - shift table provided on page 1, draw the structure of the compound. Partial credit will be given for correct structural fragments. 3X trip 2H 2H trip doub 1H 2H trip s X J J i I | 1 I l | I I u 1 O 8 6 4 2 O 307/315 EXAM IIDRAFT FALL 2010 18 PRINT NAME 7Y- (11 points) The 1H spectrum of a compound (C6H10CIZO) has five peaks. Using the chemical shifi table provided on page 1, draw the structure of the compound. Partial credit will be given for correct structuralrfragments. 3H tri 2H p tip , 1H 2H trip 2H qua IL q“ I I F 5 I ' l I I 10 8 6 4 2 307/315 EXAM II DRAFT FALLZOIO 19 PRINT NAME 1. Which of the following molecules are chiral? ‘ CH3 Cl Br CH3 H30“.- : l""”Br Br Cl 1 2 5 A all are chiral B 1 and 5 C 2 and 4 D. 2, 3 and 4 ® none is chiral 2. . Describe the relationships within each of the following pairs. /\/\ CI i H H 1 CH8 . . CH3 H E 1 2 3 ; A. all three are enantiomeric pairs 1 ® pairs 1 and 3 are enantiomers, pair 2 are identical C pairs 1 and 2 are enantiomers, pair 3 are identical D pairs 2 and 3 are enantiomers, pair 1 are identical E all three pairs show identical structures 307/315 EXAM HDRAFI‘ FALL 2010 2 PRINT NAME 3; Which of the following statements are true about the combustion of propane? 1. The reaction is always spontaneous. _ 2. The reaction is spontaneous only when a flame is present.- 3. The enthalpy change is negative and the entropy change is positive. 4. The enthalpy change is positive and the entropy change is negative. 5. The enthalpy change and the entropy change are both negative. ‘ land3 B. l and 5 C. l and 4 D. 2 and 4 E. 2 and 5 4' The correct order of increasing pKA, starting from the lowest pKA, of the following Bronsted acids 1. HClO4; 2. CH3C02H; 3. CICH2C02H; 4. FCHZCOZH; 5. e OZCCOZH A. l,2,3,4,5 1,4,3,2,5 C. 5, 2,4, 3, l D. l,5,4,3,2 E. none of the choices offered is correct 5. What color is your exam? A. White B. Pink C. Blue D. Yellow 307/315 EXAM IIDRAFT p FALL2010 3 ...
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This note was uploaded on 02/12/2012 for the course PSYCHOLOGY 101 taught by Professor Michaelleyton during the Spring '08 term at Rutgers.

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Exam2 - kfiiPRINT NAME 1X. (10 points) The (1R)~enantiomer...

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