課程名稱︰ 有機一
課程性質︰ 系上必修
課程教師︰ 汪根叢教授
開課學院： 理學院
開課系所︰ 化學系
考試時間︰ 2006/11/16
是否需發放獎勵金：是
（如未明確表示，則不予發放）
1. Please give the major product(s) for the following reaction, prodvide
stereochemistry if it is necessary.(15%)
Br(出)
╱╲╱ CH3OH
∣ ∣ ———————→ AA
╲╱╲ room temperature
CH2CH3(入)
OH(出)
╱╲╱ NaOEt
∣ ∣ ———————→ BB
╲╱╲╱╲ - EtOH
(出)↗ Br
I(入)
╱╲╱ CH3SNa
∣ ∣ ———————→ꄠ CC ﴊ ╱╲╱ acetone
3HC(出)
╱╲╱╲ (CH3)3CONa
∣ ∣ ∣ ———————→ DD
╲╱╲╱╲ 갊 ∣∣ CH3(出)
(入)H Br(出)
1) NaI acetone
(S)-2-chloropentane ———————→ EE
2) NaCN/ DMF
2.One of the following diastereomers (XX and YY) undergoes E2 reaction 50
times faster than the other. Which compound is it? (2%) Why? (4%), and
Give the products for both reactions. (4%)
╱╲ ╱╲
∣O ∣ ∣O ∣
(入)Br ╲╱ H(入) Br(入) ╲╱ CH3(入)
╲___∣╱ ╲___∣╱
╱∣갠 ╲ vs. ╱∣ ╲
(出)H ╱╲ CH3(出) (出)H ╱╲ H(出)
∣O ∣ ∣O ∣
╲╱ ╲╱
XX YY
3. (a) Provide the orbital hybridzation and structure of methyl carboncation.
(4%) (b) Compare the relative stability of the following carboncations
and give you reasons. (8%)
+
∣ ∣+ ∣
╱╲ ╱╲ ╱╲+
(1) ∣ ∣ ∣ ∣ ∣ ∣
╲╱갠 ╲╱ ╲╱
CH3 CH3
(2) ╱╲╱ ∣+
∣ ∣↖+ﴠ vs. △
╲╱
4. In an SN1 reaction of compound ZZ, please give a reasonable explanation
about the product distribution. (7%)
(入)H X(出) (入)H OH(出) OH(出) H(入)
∣╱ ∣╱ ╲∣
╱╲╱╲ ———→ ╱╲╱╲ ╱╲╱╲
∣O ∣ CH3 ∣O ∣ CH3 + 3HC ∣O ∣
╲╱ ╲╱ ╲╱
ZZ (S) (S) (R)
when X=Br 50%(S)+50%(R)
X=Cl 41%(S)+59%(R)
5.Please provide the products (4%) and give your reasons (6%) about the
relative rates for the following E2 reactions.
Br(出)
╱╲╱ E2 elimination
∣ ∣ ———————→ fast
╲╱╲╱╲
╱∣↖ CH3(出)
(出)
Br(入)
╱╲╱ E2 elimination
∣ ∣ ———————→ slow
╲╱╲╱╲
╱∣↖ CH3(出)
(出)
6. (a) Please determine the absolute configuration (R or S) of the all
chirality center(s) of the following compounds A and B. (8%) (b) For
the Fisher projection of compound C, please fill the identity of
W,X,Y and Z(4%)
CH3(出)
∣ (出)Br CH3(入) CH3
╱╲╱╲ ∣╱ CH3 ———— │
∣ ∣ ∣ ╱╲╱ ———— W─┼─X
╲╱╲╱ H ∣＼OH(入) ———— │
↖ CH2CH3 Y─┼─Z
A 雙鍵 C │
CH2CH3
7. Write the structures of the three meso diastereomers of C6H12Cl2. (6%)
8. (a) When (R)-2-chlorobutane reacts with excess NaI in acetone finally gives
a racemic 2-iodobutane, explain. (4%) (b) Explain the fact that a small
amount of NaL catalyzes the general reaction: RCl+R'ONa gives ROR'+NaCl
9. Compare the following displacement reactions and account for any difference.
(6%) (a) R2CHOH + NaBr → (b) R2ChOH + HBr →
10.Compare the relative acidity of (a) CH3CH2OH vs. CH3CH2SH (b) CH3Ch2OH vs.
CH3C00H vs. CClCOOH (c) NH3 vs H2O
11.(a) Use Hammond postulate to explain the higher relative reactivity of
(CH3)3CBr as compare to that of CH3CH2Br solvolysis in ethanol. (5%) (b)
Give the reasons why SN1 reactions favor polar solvents better than SN2
reactions. (3%)
12.Account for the following observations (a) 1-fluoro-1,1-dimethylethane is
solvolyzed only in very acidic solutions (3%), (b) in solvolysis,
1-chloro-1,1-dimethylethane is less reactive than 2-chloro-2,3,3-
trimethylbutane (3%), (c) in solvolysis, 1-chloro-1,1-dimethylethane
is more reactive than 2-chloro-1,1,1-thifluoro-2-methylpropane(4%).
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※ 編輯: falchion 來自: 203.69.188.53 (11/16 23:50)