344 - Practice Problem 3-44 Answer Propose a mechanism for...

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Practice Problem 3-44 Answer Propose a mechanism for this reaction. Practice Problem 3-45 Answer (a) Give the structures of the three separable monobromo derivatives that could form when 2-methylcyclohexanone is treated with Br 2 in the presence of HBr. There are 6 possible unique compounds, but only the sets which are NOT enantiomers (e.g. constitutional isomers and diastereomers) are separable. (b) In fact, only one of these monobromo derivatives is actually formed under these reaction conditions. Assuming that this product results from bromination of the more stable possible enol, predict which of the three isomers you drew in part (a) is formed, and explain your choice. The product will be obtained from the more stable enol tautomer, which has the more highly substituted alkene double bond (Zaitsev s rule): O H OAc O H H (plus resonance) OAc O H H OAc Cl Cl O H Cl (plus resonance) Cl O Cl H Cl O O O Br Br Me Me Me Br O Me Br O Br Me O Br Me E E E D C.I. C.I. D
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Answer Indicate which hydrogen(s) in the molecule shown below (if any) would be exchanged for deuterium following base treatment in D 2 O. Practice Problem 3-47 Answer Which of the following substances would give a positive iodoform test? (a) CH 3 COCH 3 YES (methyl ketone) (c) Acetophenone YES (methyl ketone) (b) CH 3 CO 2 H NO (carboxylic acid) (d) CH 3 CH 2 CHO NO (aldehyde) Practice Problem 3-48 Answer The base-promoted rearrangement of an a-haloketone to a carboxylic acid, known as the Favorskii rearrangement, is illustrated by the conversion of 2-chlorocyclohexanone to cyclopentanecarboxylic acid. It is proposed that NaOH first converts the a-haloketone to the substituted cyclopropanone shown in brackets, and then to the sodium salt of cyclopentanecarboxylic acid. (a) Propose a mechanism for base-promoted conversion of 2-chlorocyclohexanone to the proposed intermediate. O Me Br O OH OH major enol more substituted double bond major product OH O O D 2 O/DO OD O O D D D D D Protons attached to an C atom or an O atom are exchangable. (plus resonance)
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This note was uploaded on 10/25/2010 for the course CH 310n taught by Professor Iverson during the Summer '08 term at University of Texas.

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344 - Practice Problem 3-44 Answer Propose a mechanism for...

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