Kurt Alder was a German organic chemist who shared the 1950 Nobel Prize in Chemistry with Otto Diels for demonstrating the usefulness of the diene synthesis (see Diels-Alder reaction) in forming alicyclic compounds.

 

The Diels-Alder reaction, which involves 1,4-addition of a dienophile (examples they studied included maleic anhydride, ethyl azodicarboxylate and benzoquinone) to a conjugated diene (their examples included cyclopentadiene, acyclic 1,3-dienes, furans and anthracene) is still one of the most general methods for constructing six-membered rings.

 

Born in Königshütte, Germany (now in Poland), Alder took his PhD degree with Diels at the University of Kiel in 1926. For a time he worked in industry on polymers and synthetic rubbers, then in 1940 joined the faculty of the University of Cologne where he remained until his untimely death after a brief illness. He coauthored 173 papers which included, besides the stereochemistry and mechanism of the DA reaction, studies on the retro-DA reaction, the 'ene' reaction, and applications to natural products synthesis.