Quiz 4 in Chem 238: Mechanisms and Reactions in Organic Chemistry, Quizzes of Organic Chemistry

Download Quiz 4 in Chem 238: Mechanisms and Reactions in Organic Chemistry and more Quizzes Organic Chemistry in PDF only on Docsity! Chem 238 Winter, 2001 Quiz #4 Prof. Sasaki ______________________________________________________________________ 1. The following transformation has been observed. Assign a structure to Compound A and suggest a mechanism for the conversion of A to the final product. OH CH2OH tosyl chloride pyridine 0 °C A O hexamethyphosphoric triamide (solvent) 80 °C 2. Propose a mechanism to account for the observation that when tetramethyloxirane is treated with borone trifluoride, it is isomerized to 3,3-dimethyl-2-butanone. O CH3 CH3 CH3 CH3 BF3 CH3 O CH3 CH3 CH3 3. You saw that epoxidation of an alkene with a peracid such as peracetic acid results in addition of an oxygent atom to the alkene in such a way as to preserve the stereochemical relationships originally present in the alkene in the product epoxide. That is, cis alkene leads to cis epoxide, and trans alkene leads to trans epoxide. There is another route to epoxides that involves cyclization of halohydrins. Use cis-2-butene as a substrate to analyze carefully the stereochemical outcome of this process. What happens to the alkene stereochemistry? Br2 H2O Br OH H2O OH - O