Organic Chemistry Diels Alder Reaction

David Snyder
Experimental Date: September 16, 2011
September 21, 2011
Yu Wang
Section: Friday, 9:30 am

Diels-Alder Reaction
Abstract:
I prepared the bicyclic ring 4-cyclohexene-cis-1,2-dicarboxylic anhydride by reacting butadiene with maleic anhydride. I heated my materials in reflux in order to not lose any material to the environment after cooling and getting our crystals I washed them, and analyzed it by taking its melting point which I found to be 94-96 degrees Celsius. I also weighed the product and found its mass to be 1.286g. With maleic anhydride being the limiting reagent I found that this produced a percent yield of
Introduction:
The purpose of this lab was to have a visual and hands on example of the Diels-Alder reaction. In this example I created the bicyclic ring system 4-cyclohexene-cis 1, 2-dicarboxylic anhydride from the starting materials of butadiene and maleic anhydride. What makes the Diels-Alder reaction so important is that it’s our first real look pericyclic reactions. It’s a useful method in the preparation of cyclic compounds which can be very stable in comparison to the acyclic starting materials I used. An important piece of information about the Diels-Alder reactions is that they are stereospecific, meaning that the dienophile and diene can only interact if they meet each other in the right geometrical angles and the molecules can fit into each other the right way. In this case we need the dienophile to be cis for this reaction to proceed because the two molecules need to approach each other at an angle parallel to each other. This forms new sigma bonds and reduces the number of pi bonds which are less favorable to a molecule. The mechanism itself is a concerted one, meaning that there is no intermediate. The fact that the conjugated dienes are so reactive are due to the pi system from the