Naturalproductman’s Blog

Hey, is that a natural product?!

A Michael/Conia-ene Cascade Reaction

Posted by naturalproductman on December 23, 2009

There are a lot of biologically active compounds out there with 5,7-bicyclic ring systems and because of these compounds exist, many different approaches for obtaining 5,7-ring systems are attempted.  Chi-Sing Lee and co-workers at Peking UniVersity Shenzhen Graduate School have recently published in Organic Letters on the synthesis of clavukerin A, a natural product that possesses this 5,7-bicyclic ring system.  The carbon skeleton is interesting, but I have to admit that the new reaction that was developed is even more interesting!  The starting substrate is an alpha,beta-ketone activated with an electron withdrawing group on the alpha position with an alkyne and an aldehyde.  Basically, they use a secondary amine (diethylamine) to do some enamine chemistry – specifically, a Michael addition of the aldehyde onto the enone and then with the presence of zinc (II) iodide, a Conia-ene reaction occurs to form the five membered ring.

michael conia ene


OL paper

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