Quiz2cor_E - your answer with a mechanism (2 points). O...

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CHM 2123, Quiz #2: Regioselective Epoxidation, Syn Dihydroxylation with KMnO 4 and Electrophilic Additions to Alkenes MARKING SCHEME Posted: September 17, 2009 Due: September 21, 2009, before 5 pm 1. Epoxidation réactions are often regioselective as the rate of reaction depends on the electron density of the alkene. Draw the final product (1 point) with relative stereochemistry and explain your answer (2 points). C 6 H 5 CO 3 H (1 equiv.) CHCl 3 , 10 min 0 °C O CH 3 O O CH 3 (1) The more nucleophilic electron rich double bonds are epoxidized more rapidly. (2) The alkene on the right is deactivated by an electron withdrawing group (ketone), while the one on the left is trisubstituted with only alkyl substituents (more electron donating). 2. The acid-catalyzed hydrolysis of epoxides gives complementary alkene dihydroxylation products. Draw the final product (1 point) including relative stereochemistry and support
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Unformatted text preview: your answer with a mechanism (2 points). O HCl, H 2 O OH OH O + H + O H H 2 O OH OH 2 OH OH- H + Arrows have to be present for the attack of water on the protonated epoxide. 3. A student wants to carry out an electrophilic addition of iodine (M.W. 253.81) to 2.5g of linoleic acid (M.W. 280.45) in 40 mL of CH 2 Cl 2 . Calculate the volume of iodine solution (30% w/v in CH 2 Cl 2 ) necessary for complete addition to this compound. Show your work. (3 points) 2.5 g 280.45 g/ mol = 0.008914 mol 0.008914 mol x 253.81 g/ mol = 2.262 g = 300 mg 1 mL 2262 mg x mL x = 7.54 mL There are two alkenes to react for complete addition : 7.54 mL x 2 equiv = 15.08 mL ii. Draw the final product, including the correct relative stereochemistry. (1 point)...
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This note was uploaded on 01/13/2010 for the course CHM chm2526 taught by Professor Louise during the Spring '09 term at University of Ottawa.

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Quiz2cor_E - your answer with a mechanism (2 points). O...

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