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Summ10Ex3 - "Grade or Education" =1 CHEM 2261/01...

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Unformatted text preview: "Grade or Education" =1 CHEM 2261/01 Summer 10 Exam 3 Chapters 7-9 Two curved—arrow mechanisms are shown for the reaction of 4—bromocyclohexanol with HO' to form substitution products. Figure out the substitution mechanism(s) for the reaction of cis—4—bromocyclohexanol and trans—4—bromocyclohexanol with HO' to form product(s). Choose the CORRECT statement from the multitple choices. .. :oH . .. “UP. Br =,, mechanism 1 fldH U mechanism 2 trans—4—bromocyclohexanol cannot react by either mechanism. cis—4—bromocyclohexanol undergoes mechanism 1 . A B __ C. Both cis—4—bromocyclohexanol and trans—4—bromocyclohexanol undergo mechanism 1 . D Neither cis—4—bromocyclohexanol nor trans—4—bromocyclohexanol undergo mechanism 2 . E __ . cis—4—bromocyclohexanol undergoes mechanism 2 . Rationale: Chapter 9 Problem 55a 2- Find the MAJOR product of the Diels—Alder reaction shown below among the numbered structures shown below the reaction. Make certain that you use the preferred alignment of the reactants to generate the major product. Pick the choice which gives the number found under the correct structure of this product. 0 || CH2:CH—c—_CH2 + CHECH-C-CHS —> ? __ A. 4 __ B. 3 __ C. None of the numbered structures is the major product of this reaction. __ D. 2 __ E. 1 Rationale: Chapter 7 Problem 71 b 3- For the target compound whose structure is shown below choose the multistep synthesis which could be used to prepare it from the given starting material. .9 CH:CH2 CH-ZC-H —> A First: Bra/CHZCIZ; Next: excess 'NHZ; Finally: HZSO4/HZO B First: Bra/CHZCIZ; Next: excess 'NHZ; Finally: HZSO4/HgSO4 —— C- First: Bra/CHZCIZ; Next: excess 'NHZ; Finally: 1. disiamylborane and 2. HO', H202, H20 D First: Brz/HZO; Next: 'NHZ —— E- First: HBr/CHZCIZ; Next: 'NHZ; Finally: 1. BH3/THF and 2. HO', H202, H20 Rationale: Chapter 9 Problem 31 b Indicate whether the alkyl halides listed in the table below will give primarily substitution products (S), only elimination products (E), both substitution and elimination products (S & E), or no products (X) when they are treated with the reagents under the reaction conditions shown in the table below. Put the correct abbreviations for substitution (S), Elimination (E) or no reaction (X) in the product column of the table for each reaction shown. These reactions are designated a1 through b4 in the multiple choices as presented in the table. Pick the CORRECT statement from the multiple choices. — — — m— — — — m— Br Br/\/\ A/ Br B 1-bromobutane AK 2—bromobutane X 1 3 1-bromo-2—methylpropane 2—bromo-2—methylpropane 2 4 Reaction b4 gives primarily substitution products. Reaction a2 gives both substitution and elimination products. A B C. Reaction a1 gives no products. D Reaction b3 gives only elimination products. E Reaction a4 gives no products. Rationale: Chapter 9 Problem 22 5- Rank the ions whose structures are shown below in order of DECREASING nucleophilicity in methanol (strongest nucleophile listed first). 0 || _ _ - CH-BC-O CH-SCH-ZS CHéCHéo 1 2 3 __ A. 1 >3 >2 __ B. 3 >2 >1 __ C. 2 >1 >3 __ D. 1 >2 >3 __ E. 2 >3 >1 Rationale: Chapter 8 Problem 42a 6. Pick the number of the structure which is NOT a correct resonance contributor for the ion labelled 1 , shown below. \\ 01 + \LQ: \_©+3 WPOW? com-5N0: Rationale: Chapter 7 Problem 44b 7- Find the elimination product(s) of (ZS,3S)—2—chloro—3—methy|pentane + high concentration of CH30' among the numbered structures below. Choose the CORRECT product(s) of this reaction. CH3 CH3 C _ H2 CH CH3 CH-ZCHS CH3 CH3 3 — H CH-ZCHs H CHZCH3 H‘ CH3 H CH:CH2 1 2 3 4 1 and 3 are both products of this reaction. is the product of this reaction. is the product of this reaction. __ A. __ B. __ C. __ D. is the product of this reaction. E. “Nd-h is the product of this reaction. Rationale: Chapter 9 Problem 48a 8. Figure out which species is the more stable of each of the labelled pairs shown below. A pair of species share the same letter, like a1 and a2 . Choose the statement which is CORRECT about the relative stabilities of these pairs of species. ii“: . 9 9 CH-3CH-ZC-CH2 CH-SCH-ZCHICH-CHZ CH-3C-CHZCH2 CH-sC-CHZCH-CHB a1 a2 b1 b2 9' 9' || CH-3CH-CH2CH2 CH-SCZCH-CHS CH-3c-NH2 CH-3c-NH2 c1 c2 d1 d2 A c1 is more stable than c2 . B None of the other choices is correct. __ C. d2 is more stable than d1 . D a1 is more stable than a2 . __ E. b2 is more stable than b1 . Rationale: Chapter 7 Problem 7 9- How could the compound below be synthesized using a Diels—Alder reaction? Choose the CORRECT structures of the two substances which react with one another to form this Diels—Alder product. CO2CH3 COZCH3 (302cm3 g ICIDH-COZCHS CH 1 2 3 4 5 6 Compounds 5 and 6 can be used in this reaction. Compounds 1 and 2 can be used in this reaction. A B C. Compounds 4 and 6 can be used in this reaction. D Compounds 3 and 4 can be used in this reaction. E Compounds 5 and 3 can be used in this reaction. Rationale: Chapter 7 Problem 64b 10. Choose the CORRECT major substitution product(s) of the reaction shown below. Choose the correct stereoisomer(s) if stereoisomer(s) is/are produced. 3 CH 3 CH3 _,CH3 CH3 CH3 OCH3 Q OCH3 OCH3 OCH OCH 1 2 3 4 2 and 5 are the major substitution products of this reaction. 1 , 2 , 3 , 4 and 5 are the major substitution products of this reaction. A B C. 1 is the major substitution product of this reaction. D 2 , 3 , 4 and 5 are the major substitution products of this reaction. E 3 and 4 are the major substitution products of this reaction. Rationale: similar to Chapter 8 Problem 25d 1 1- Shown below is a curved—arrow mechanism for converting structure 1 into structure 5 . Which structure has the curved arrow(s) associated with it drawn INCORRECTLY? CH H o + I 3 9H3 2 CH3 CHtBr —. H —> + 1 2 + Br' 3 T + 0|:\I OH H O: CH 2 CH 4 5 | | W909“? WNW-hi Rationale: Chapter 8 Problem 62a l 2- Choose the CORRECT substitution product(s) of the reaction of (ZS,BS)—2—chloro—3—methy|pentane with a high concentration of CH30' from below. Choose the correct stereoisomer(s) if stereoisomer(s) is/are produced. CH3 CH3 CH3 CH3 H OCH3 CH30 H H OCH3 CH30 H H CH3 H CH3 H30 H H30 H CHZCHS CH2CH3 CHZCHS CHZCHQ 1 2 3 4 2 is produced by this reaction. 3 is produced by this reaction. A B __ C. 1 and 2 are produced by this reaction. D 4 is produced by this reaction. E __ . 3 and 4 are produced by this reaction. Rationale: Chapter 8 Problem 52a 1 3. Use the numbered structures shown below to choose the CORRECT statement from the multiple choices. *0 '31 %~CI CI a /\ O/\ CI c1 b2 c2 c2 will react with H20 faster than c1 will. (CH3)3CBr will react faster with CH3CHZOH than it will with H20. A B —— C- b1 will react with HO_ faster than b2 will. D (CH3)2CHS_ will react faster with a than CH35_ will. E —— - b2 will not react with HO_. Rationale: Chapter 8 Problem 48 14. Find the structures of the major 1,2 and 1,4 addition products resulting from the reaction of diene a (shown below) with HCI. Figure out which structure is the kinetic product of this reaction and which structure is the thermodynamic product. Choose the CORRECT statement from the multiple choices. CH CH 2 3 II a C CH2 CI CH3 CH2CI CH3 CH3 Cl 1 2 3 4 5 The kinetic product has structure 2 and the thermodynamic product has structure 4 . The kinetic product has structure 4 and the thermodynamic product has structure 2 . A B __ C. Both the kinetic and the thermodynamic products have structure 5 . D The kinetic product has structure 1 and the thermodynamic product has structure 3 . E __ . The kinetic product has structure 3 and the thermodynamic product has structure 1 . Rationale: Chapter 7 Problem 31a 15- Figure out which speciec in each of the pairs shown below is more stable. Pairs of structures share the same letter, like a1 and a2 . Pick the CORRECT statement from the multiple choices. — — + + CH3CHCH2CH3 CH3CH2CH2CH2 CHZCHZCH=CH2 ()H3CHCH=CH2 a1 a2 c1 02 + + CHSCHCHZCHS CH3CHZCHZCH2 b1 b2 CHZCHZCH=CH2 CH36HCH=CH2 CHéCIDH-CHZCHZ CH;Q,CH-2C|>=CH2 d1 d2 CH3 CH3 e1 92 A c1 is more stable than 62 . 3 d2 is more stable than d1 . —— C- e1 is more stable than 62 . D a1 is more stable than a2 . —— E- b2 is more stable than b1 . Rationale: Chapter 9 Problem 35(a,b,c,d,e) 10. 11. 12. 13. 14. 15. Answer Key "Grade or Education" CHEM 2261/01 Summer 10 Exam 3 Chapters 7-9 1 ...
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This note was uploaded on 12/30/2011 for the course CHEM 2261 taught by Professor Crowe during the Fall '08 term at LSU.

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Summ10Ex3 - "Grade or Education" =1 CHEM 2261/01...

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