課程名稱︰有機化學乙上 課程性質︰必帶 課程教師︰楊吉水 開課學院：工學院 開課系所︰化工系 考試日期（年月日）︰2011/10/20 考試時限（分鐘）：110 是否需發放獎勵金：是 （如未明確表示，則不予發放） 試題 : 二. essay questions(問答題, 66分) 1.Draw all significant resonance structures for each of the following compounds (a) OH H (b) +│ / ／＼〃＼／ ／＼N ║ │ +｜ │ │ ＼〃 ＼／ 2.Consider the following two compounds: O O ∥ O ∥ ／＼／〝／ ＼ ／＼／〝　 　　 ∥ ∣　　　　 　　∥ ｜ ＼〃　　　 　　＼〃＼ ／　 O Compound A Compound B (a)Identify which of these two compounds has greater resonance stabilization. (b)Would you expect compound C (below) to have a resonance stabilization that is more similar to compound A or to compound B? O O— ∥ ｜ ／＼／〝 　　　　 ∥ ∣ ＼〃 Compound C 3.For each reaction below, draw the mechanism(curved arrows) and then predict which side of the reaction is favored under equilibrium conditions. (a) S S ∥ - ∥ ／＼ + HS → ／＼ - + H2S SH　　　　　　　　　　　　S 　 (b) H H / -／ - \ ／ O N → O N _| ｜ _| ｜ /＼／ /＼／ 4.Rank the following anions in term of increasing basicity. - O \/ HO ∥ ／＼ - ／＼ - ／＼ - O O O 5.Consider the following compound with molecular formula C4H8O2: ／＼ ┌┐ OH O┘ (a)Draw a constitutional isomer that you expect will be approximately one trillion(10^12) times more acidic than the compound above. (b)Draw a constitutional isomer that you expect will be less acidic than the compound above. (c)Draw a constitutional isomer that you expect will have approximately the same pKa as the compound above. 6.What is the systematic name for each of the following compounds: (a) │ (b) ＼／＼ 　 /| │ │ ||／ ／＼／＼／＼ ／| ＼ │ /／\＼/ 7.What are the relative energy levels of the three staggered conformations of 2,3-dimethylbutane when looking down the C2-C3 bond? Draw the three conformations and then do comparison. 8.Consider the following tetra- cyclohexane: OH ◤ ＿ ／＼◤ │ │ _￥＼／ ／ ≒ Cl (a)Draw both chair conformation of this compound. (b)Determine which conformation is more stable. 9.consider the structures of cis- decalin and trans-decalin: H H | | H ／/＼／/ /＼／/＼／/ ＼/／＼/ /／＼/／＼/ | | | /／ H cis-decalin trans-decalin (a)Which of these compounds would you expect to be more stable? (b)One of these two compounds is incapable of ring flipping. Identify it and explain your choice. TM 10.Paclitaxel (marketed under the trade name Taxol ) is found in the bark of the Pacific yew tree, Taxus berevifolia, and is used in the treatment of cancer. ／〝 ∥ ｜ O ＼〃 〝－O O OH ｜ ／ ◥ ∥ ◤ 〃＼ /￣ ＼▼／\ O NH O ＼〃＼∠ ｜ ∣ ≒ ∥ ∣ ｜_／≒＼/◥O ／〝／＼／＼￥＼／◣￥H ￥◣/ ∥ ｜ ≒ O OH O O ＼〃　 OH ╴ ／ ＼／ 　 O￣｜ ∥ 〃＼ O ｜ ∥ 〝 ／ http://ppt.cc/dTbw (a)How many chitrality centers does this compound possess? (b)Assign the configuration of each chirality center. Draw the structure in your answer sheet and label each chirality center with R or S. 11.Draw a Fischer projection for each of the following compounds, placing the -CO2H group at the top. (a) OH O ≒ ∥ ／＼／＼／＼ HO ≒ ◣ OH OH OH (b) OH O ◤ ∥ ／＼／＼／＼ HO ◢ ◣ OH OH OH (c)Determine the relationship between the above two compounds. --

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