Problems for Chapter 34
PROBLEM 1
Predict the structure of the product of this Diels-Alder reaction.
PROBLEM 2
Comment on the difference in rate between these two reactions.
PROBLEM 3
Justify the stereoselectivity in this intramolecular Diels-Alder reaction.
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Problems to accompany Organic Chemistry
PROBLEM 4
Explain the formation of single adducts in these reactions.
PROBLEM 5
Suggest two syntheses of this spirocyclic ketone from the starting materials
shown. Neither starting material is available.
PROBLEM 6
Draw mechanisms for these reactions and explain the stereochemistry.
Problems for Chapter 34 – Pericyclic reactions 1: cycloadditions
PROBLEM 7
Give mechanisms for these reactions and explain the regio- and stereochemical
control (or lack of it!). Note that MnO2 oxidizes allylic alcohols to enones.
PROBLEM 8
Suggest a mechanism for this reaction and explain the stereo- and regiochemistry.
PROBLEM 9
Photochemical cycloaddition of these two compounds is claimed to give the
diastereoisomer shown. The chemists who did this work claimed that the
stereochemistry of the adduct is simply proved by its conversion into a lactone on
reduction. Comment on the validity of this deduction and explain the
stereochemistry of the cycloaddition.
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Problems to accompany Organic Chemistry
PROBLEM 10
Thioketones, with a C=S bond, are not usually stable. However, this thioketone is
quite stable and undergoes reaction with maleic anhydride to give an addition
product. Comment on the stability of the thioketone, the mechanism of the
reaction, and the stereochemistry of the product.
PROBLEM 11
This unsaturated alcohol is perfectly stable until it is oxidized with Cr(VI): it then
cyclizes to the product shown. Explain.
PROBLEM 12
Give mechanisms for these reactions, explaining the stereochemistry.