Lab 5: Diels-Alder Reaction
The laboratory procedure used was written by Dr. John Barbaro of Rocky Mountain College.
The Diels-Alder reaction is a well known example of cycloaddition chemistry. It is commonly
known as [4+2] Cycloaddition. The reactants in the Diels-Alder reaction are a 1,3-diene and an
alkene called the dienophile. The dienophile usually contains an electron-withdrawing group
that is in conjugation to the double bond, making the double bond “electron poor”, thus
initiating the addition reaction. The double bond of the dienophile adds to the diene to give a
product that has a six-membered ring.
EWG
+Solvent
Heat
EWG
The Diels-Alder reaction occurs through a concerted step (in a single step). Two chemists, Otto
Diels and Kurt Alder, were awarded the Nobel Prize in Chemistry in 1950 for this reaction.
Diels-Alder Reaction (Diene Synthesis).
FIRST CITATION: O. Diels and K. Alder, Ann. 460, 98 (1928); 470, 62 (1929) Ber. 62, 2081, 2087
(1929)
Stereoselectivity:
The Diels-Alder reaction is stereospecific. The configuration of reactants are maintained during
the Diels-Alder reaction. In the case of cyclic dienes, these give stereoisomeric products as
well.
In order to see what the products of these reactions look like, please click here! VERY COOL
LINK!
If the link above does not work on your PC, you might need to download the program, Jmol.
Click here to go to the download page.
Also, since this is a synthesis, two ADDITIONAL steps are
ALWAYS performed: draw a correct mechanism for the
production of the product from the starting materials and
PROPERLY calculate a percent yield. The mechanism is part of
the prelab; the percent yield is part of the post lab
Properly assembled, your reflux apparatus will look like this:
PLEASE NOTE two clamps, not clips!
