HT1-04an - S ome Answers to Hour Examination #1, Chemistry...

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Some Answers to Hour Examination #1, Chemistry 302/302A, 2004 1. In this variation of the Diels-Alder reaction, both the diene and the dienophile are cyclic compounds. The first complication is to decide whether the reaction will pass over an endo or exo transition state. In fact, the cycloadduct has the endo stereochemistry, and this reaction is normal in that respect + O O H H O O C 11 H 10 O 2 note: endo You may have noticed that the product of this Diels-Alder reaction still has a double bond with two attached carbonyl groups. This carbon-carbon double bond is also a quite reactive dienophile. When this reaction is run in the presence of two equivalents of 1,3-cyclopentadiene, a 2:1 adduct is readily formed: H H O O H H O O H H C 16 H 16 O 2 double endo 2. Adamantene is unstable because the π bond is a very poor one.The orbitals do not overlap at all well. very poor overlap = reverse Diels-Alder 1 2 The reaction succeeds, but the unstable adamantene undergoes a reverse Diels-Alder reaction. Remember: all cyclohexenes are related to a diene and a dienophile through the Diels-Alder reaction.
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3. Solvolysis gives pentadienyl cation
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This note was uploaded on 03/07/2010 for the course ORGO 1 AND V.0243 taught by Professor Jones during the Spring '10 term at NYU.

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HT1-04an - S ome Answers to Hour Examination #1, Chemistry...

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