※ 引述《juiceshih (果汁)》之铭言： : ※ 引述《FireHell (冥煌 = 好硬)》之铭言： : ※ [本文转录自 NTU-Exam 看板] : 作者: falchion (流浪狗) 看板: NTU-Exam : 标题: [试题] 95上 汪根丛 有机化学一 第一次小考 : 时间: Wed Oct 18 03:30:51 2006 : 课程名称︰有机化学一 : 课程性质︰系上必带 : 课程教师︰汪根丛 : 开课系所︰化学系 : 考试时间︰2006/10/17 : 是否需发放奖励金：是 : （如未明确表示，则不予发放） : 试题 : : 1.Please compare the relative proton acidity(pKa) of the following compounds : and give your reasons.(10%) : H H H O H O : | ┌─┐ | ┌─┐ | ∥ ┌─┐ | ∥ ┌─┐ : (a) H-C-│H │ H-C-O-│H │ H-C-C-O-│H │ H-C-C-O-│H │ : | └─┘ | └─┘ | └─┘ | └─┘ : H H H Cl : 这个我就不会了..... 囧 1 2 3 4 O、Cl都是高电负度，会使Hδ+，H越δ+越容易解离 =>acidity越大、pKa越小 =>acidity:4>3>2>1 pKa:1>2>3>4 不过根据教授的说法，4比3酸是因为4的共轭硷因为inductive effect而有 charge interaction，可以增加稳定度。 "3和4"比"1和2"酸，是因为3和4的共轭硷有共振结构，可以增加稳定度。 这些不妨也可以写进去吧~~~ : (b) 3HC-CH3 2HC＝CH2 HC≡CH : 2.(1)Give the IUPAC systematic names of the following compounds.(10%) : ∣ : ╲╱ Cl : ∣ ∣ ∣ ∣ ∣ ∣ ∣ : (a) ╱∣╲╱∣╲ (b) ╲╱╲╱╲╱╲╱╲ (c) ╱╲╱╲╱╲╱ : ∣ ∣ ∣ ∣ : Cl ╱╲ ╱ Br : ∣ : ╱ : ∣ ▕(指向外的粗线) : (d) ╱╲ (e) ╱╲ : ∣ ∣ ∣ ∣ : ╲╱╲ ╲╱╲(这里是向内的虚线) : ∣ Cl ▽ : ╱∣╲ : (2)Accirding to the following IUPAC names, draw the corresponding : structures.(10%) : (a)2,3-dimetheyl-5-(2-methylbutyl)decane : (b)6-(1,2-dimethylpropyl)-4-propyldecane : (c)4-bromo-2chloro-1-methylcyclohexane : (d)cis-1-ethyl-3-isopropylcyclopentane : (e)cyclopentylcyclohexane : 3.(1)Give you reason for which of the following diaxial-substituted : cyclohexane has the highest energy.(4%) : CH3 CH3 : ∣ ∣ : ∕╲╱ ∕╲╱ ∕╲╱ : ╱╲∕ ╱╲∕ ╱╲∕ : ∣ ∣ ∣ ∣ : Cl Cl CH3 Cl : (2)Draw the most stable conformation of the following molecules.(6%) : CH3 CH3 : ▕ Cl ▕ : ╱╲╱(虚线) ╱╲ : (a) ∣ ∣ ﴠ (b) ∣ ∣ : ╲╱ (虚线)╱╲╱╲(虚线) : ╱∣╲ CH3 CH3 : 4.(1)Which of the following conformers of isobutyl chloride is the most : stable,why?(4%) : H CH3 H H CH3 Cl : ╲︵︵︵╱ ╲︵︵︵╱ : (a) ( ∣ ) (b) ( ∣ ) : ( ╱╲ ) ( ╱╲ ) : H︶︶︶CH3 H︶︶︶CH3 : ∣ ∣ : Cl H : (2)Draw the most stable and unstable eclipsed conformers of isobutyl : chloride.(6%) : 5.For chemical reactions shown below, the starting W firstly transforms to : intermediates A and B, then subsquently from products C and D. Based on : Curtin-Hammett principle explain how you can control the product formation : ratio of C to D.(15%) : W : Ea2 ∣ Ea1 : <---- ↓ → Ea3 : C → 〔 A ← B 〕→ D given: Ea3 > Ea2 > Ea1 : 6.Given your reasons for the following observations of bond dissociation : energy.(15%) : (a) 3HC-X X = F Cl Br I (3%) : 138 103 87 71 : (b) 3HC-X X = F OH NH2 (3%) : 136 119 108 : R = CH3CH3 (CH3)2CH (CH3)3C : (c) R-H 101 98.5 96.5 (6%) : (d) R-Cl 84 84 85 (3%) : 还有这个的c d C链为推电子基，会使Hδ+的程度变小，Clδ-的程度变大，C链中C数越多 =>H越不易解离、Cl越容易解离 不过我不确定这样的解释教授or助教能不能接受 : 7.Based on Hammond postulate, give your reason for the selectivity of the : following halogenations.(20%) : F : ∣ : CH3 CH2 CH3 : ∣ F2 ∣ ∣ : 3HC——H ——→ 3HC——H + 3HC——F : ∣ hνor △ ∣ ∣ : CH3 CH3 CH3 : 9 ： 1 : CH3 CH3 : ∣ Br2 ∣ : 3HC——H ——→ 3HC——Br only product : ∣ hνor △ ∣ : CH3 CH3 ---------------------------------------------------------------------------- 仅供参考... --

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