Transcription

1 COURSES > ORGANIC CHEMISTRY (CH_336_001_S2006) > CONTROL PANEL > TEST MANAGER > TEST CANVAS Test Canvas Add, modify, and remove questions. Select a question type from the Add Question drop-down list and click Go to add questions. Use Creation Settings to establish which default options, such as feedback and images, are available for question creation. Add Creation Settings Name Quiz 2 Description Second Weekly Quiz Instructions Please select the best option to answer each question. Question Select the product of the following reaction. Question Select the best synthesis of methyl t butyl ether. Convert t butanol to its p-toluenesulfonate using TsCl, then react with sodium methoxide. React 2-methylpropene with methanol in a strong acid like H 2 SO 4 React 3,3-dimethyl-2-butanone with strong acid to induce an alkyl shift to oxygen. React methylmagnesium iodide (made from CH 3 I and Mg) with t butanol. 1 of 5 4/14/2006 5:20 PM

2 Question Attempting to make an ether by using an alkoxide to do an S N 2 substitution on a primary acohol fails. Why? The only possible leaving group is HO -, and this is generally not a good leaving group. The concentration of H + is too low under basic conditions to activate OH as a leaving group. Proton exchange between the alkoxide intended as nucleophile and the alcohol intended as the electrophile occurs. All three answers contribute to some extent. Question Why is making a p-toluenesulfonate a good first step for performing a net nucleophilic substitution for the OH group in an alcohol? The p-toluenesulfonate has no free OH group to be deprotonated by the nucleophile, and the electronegativity of the toluenesulfonyl group enhances the polarization of the C-O bond and make TsO - a very good leaving group. The p-toluenesulfonate undergoes rapid, spontaneous substitution by chloride, and the alkyl chloride is a good substrate for nucleophilic substitution. The stability of the p-toluenesulfonate prevents eliminations from occurring, particularly with toluenesulfonates made from tertiary alcohols. None of the three answers above are valid; p-toluenesulfonates cannot be used as substrates for nucleophilic substitution. Question Select the best name for the following compound. 1-methyl-1,2-trimethyleneoxirane Epoxycyclohexane 1-methylcyclopentyl ether 1-methylcyclopentene oxide Question Select the easiest means of distinguishing the following two compounds. 2 of 5 4/14/2006 5:20 PM

3 1 H NMR: the alcohol causes a different chemical shift for adjacent C-H protons than does the epoxide. 13 C NMR: there is one oxygen-bearing carbon for the alcohol and two for the epoxide. IR: The alcohol will show a strong O-H stretching band that will not be present for the epoxide. Mass spectrometry: the two compounds have different masses. Question Select the major product formed in the following multistep sequence: methylcyclohexanol + H 2 SO 4 + heat mcpba LiC CPh Neutralize with mild H + 3 of 5 4/14/2006 5:20 PM

4 Question Select the structure that best fits the given data. Molecular formula: C 8 H 8 O 1 H NMR: 7.2 m, 5H 3.80 dd, 1H, J = 6, 6 Hz 3.15 dd, 1H, J = 6, 3 Hz 2.80 dd, 1H, J = 6, 3 Hz 13 C NMR: 135, 129, 128, 125, 53, 50 ppm. Question Select the product of the following reaction. 4 of 5 4/14/2006 5:20 PM

5 Question Select the product for the following reaction: 5 of 5 4/14/2006 5:20 PM