The Diels-Alder reaction of thebaine with various dienophiles was pioneered and developed by K.W. Bentley; his work led to the discovery of buprenorphine, a potent opioid analgesic with low abuse potential. I was fortunate to have had the opportunity to carry out Diels-Alder reactions on thebaine, to yield various esters at the 7α-position in good yield.
The reaction pathway used was relatively simple; modern transesterification catalysts would facilitate a shorter synthesis today.
An animation will open in a new window when the reaction scheme is clicked. Mousover
and click the image on the right for basic information about the Diels-Alder reaction.
Move your mouse over the text and image in the second new window for more information.
Thermally allowed Diels-Alder reactions generally proceed through an aromatic transition state. Three new bonds are formed, of which two are sigma bonds.
