Problem Set 11-02-17 Answers PDF

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Problem Set 11-02-17 Answers...

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1) Depicted below is the reaction of a diene under two different conditions.

a) Please draw the mechanism for each transformation and indicate the major product. b) Please represent the starting material, intermediate(s), and product(s) on a reaction coordinate diagram, paying attention to relative energies of each species and transition states. a)

b) Keep in mind: both products share the same intermediate! (Forgive the sharp edges, rxn. coord. diagram was made in paint!)

2) Please identify whether the following compounds are aromatic, antiaromatic, or non-aromatic:

3) Below are two 10-π electron aromatic compounds. Naphthalene is colorless and has no dipole, whereas azulene is deep blue and has a dipole.

a) Please indicate the direction of this dipole and explain its origin. b) One ring in azulene can be regarded as electrophilic, while the other can be regarded as a nucleophile. Please identify which ring can act as a nucleophile/electrophile.

a) Can be regarded as one 6-π electron cyclopentadienyl anion and one 6-π electron cycloheptadienyl cation, both of which have aromatic character. b) The 7-membered ring is acting as an electrophile due to the electron deficiency, while the 5-membered ring is acting as a nucleophile due to its electron richness. 4) Please indicate the product(s) of the following Diels-Alder reactions (please keep in mind regio- and stereoselectivity)

5) At room temperature, a bottle of cyclopentadiene will eventually convert to dicyclopentadiene through a Diels-Alder reaction with another molecule of the same compound. Please show the mechanism leading to one of the products of this reaction....