Cycloaddition Reactions cont'd
For each of the cycloaddition reactions on the left, predict the major organic product. Pay particular attention to the stereochemistry of the reaction.Click the mouse on the reactant molecules to view the answer;
click on the arrow for help in visualizing the cycloaddition.
The cis-trans diene will react with the dienophile to give a cyclohexene in an approximate "boat" conformation. This will rapidly convert to the more stable "chair" conformation, placing both methyl groups 1,4-equatorial, or trans- relative to each other ( cis-trans yields trans-). You should note that since this is a cyclohexene ring, it is an approximation to show the product in "chair" and "boat" conformations.
The trans-trans diene will react with the dienophile to give a cyclohexene in an approximate "boat" conformation. This will rapidly convert to the more stable "chair" conformation, placing the methyl groups 1,4- equatorial-axial, or cis- relative to each other ( trans-trans yields cis-). You should note that since this is a cyclohexene ring, it is an approximation to show the product in "chair" and "boat" conformations.
The trans-trans diene will react with the trans-dienophile to give a cyclohexene in an approximate "boat" conformation. This will rapidly convert to the more stable "chair" conformation, placing (for the diene) the methyl groups of the diene 1,4-equatorial-axial, or cis- relative to each other ( trans-trans yields cis-), and the methyl groups of the dienophile 1,2-diequatorial or trans- relative to each other (trans-dienophile yields trans-product). You should note that since this is a cyclohexene ring, it is an approximation to show the product in "chair" and "boat" conformations.
The cis-trans diene will react with the dienophile to give a cyclohexene in an approximate "boat" conformation. This will rapidly convert to the more stable "chair" conformation. You should note that since this is a cyclohexene ring, it is an approximation to show the product in "chair" and "boat" conformations.
The trans-trans diene will react with the dienophile to give a cyclohexene in an approximate "boat" conformation. This will rapidly convert to the more stable "chair" conformation. You should note that since this is a cyclohexene ring, it is an approximation to show the product in "chair" and "boat" conformations.
The trans-trans diene will react with the trans-dienophile to give a cyclohexene in an approximate "boat" conformation. This will rapidly convert to the more stable "chair" conformation. You should note that since this is a cyclohexene ring, it is an approximation to show the product in "chair" and "boat" conformations.
