Examination%20_2%20Spr%202008

Examination%20_2%20Spr%202008 - Name CHEM 235 – ORGANIC...

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Unformatted text preview: Name CHEM 235 – ORGANIC CHEMISTRY II Spring 2008 Mid‐Term Examination 2 This examination is worth 100 points out of a total of 700 possible points for this course, and consists of seven questions plus a bonus question. You are required to provide answers for all seven questions, but you may not be required to answer all parts of a question, so read the questions carefully. Where you are not required to answer all parts of a question, you must indicate clearly which parts you wish to have graded. Question 1 (15 points). Provide systematic names for three of the five structures shown below. Include stereochemical descriptors where required. OH O OH OH O HO OH HO Question 2 Name (15 points). Predict the outcomes of the two reactions below, with reference to the relevant reaction mechanism(s). You must include the mechanism(s) as part of your answer, but you may use additional structures or diagrams to explain your answer. Indicate which of the reactions would be appropriate for the synthesis of tert‐butyl hexyl ether. 1) NaH/THF 1) NaH/THF (A) OH 2) Br (B) OH 2) Br Question 3 OH OH Name (8 points). Choose two of the three sets of compounds below, and rank the compounds in each set in order of increasing acidity (1 = most acidic, 4=least acidic). OH O2N Cl OH SET A F OH OH F OH Cl OH SET B F OH OH H3C NC OH H3CO OH SET C Question 4 (15 points). Provide examples of the following (a) A poor leaving group (b) A good leaving group (c) A reaction that converts a poor leaving group into a good leaving group (d) An acid with a nucleophilic conjugate base (e) An acid with a non‐nucleophilic conjugate base (f) A compound that contains an electrophilic carbon atom (g) A compound that contains a nucleophilic carbon atom Question 5 1) CH3MgI/THF O 2) H+/H2O H2SO4/H2O OH ∆ Na2Cr2O7 OH H+/H2O KMnO4 H+/H2O O2N NO2 Br CN benzene ∆ CN 1) NaNH2/NH3/-50oC Br O H2 Pd/charcoal 2) O NaNH2/NH3 Name (21 points). Predict the outcomes (including regio‐ or stereochemical outcomes) of seven of the following eleven reactions. 1) NaBH4/EtOH O 2) H+/H2O benzene O O ∆ Na+ CH3CH2OCH3CH2OH Question 6 Name (12 points). Predict the outcome of the reaction below, with reference to the reaction mechanism. You must include the mechanism as part of your answer, but you may use additional structures or diagrams to explain your answer. HF/H2O O Question 7 (14 points). Provide structures for two of the three systematic names given. 15‐crown‐5 2‐nitro‐4‐methylphenol (R)‐7‐methyloct‐4‐yn‐2‐ol BONUS H3CH2CH2CO CO2CH3 CO2CH3 from Name (8 points). Provide a rational synthesis for the target shown, starting from the materials given. CO2CH3 CO2CH3 no other compound may exceed 6 carbon atoms in size ...
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