Enantio- and diastereoselective total synthesis of EI-1941-1, -2, and -3, inhibitors of interleukin-1β converting enzyme, and biological properties of their derivatives

The first asymmetric total synthesis of EI-1941-1, -2, and -3, inhibitors of the interleukin-1β converting enzyme (ICE), has been accomplished, starting from a chiral epoxy iodoquinone 11, a key intermediate in our total synthesis of epoxyquinols A and B. Despite a failure to synthesize the inhibitors by our postulated biosynthetic route, we were able to diastereoselectively synthesize them via an intramolecular carboxypalladation with the key steps being a 6-endo cyclization mode followed by β-hydride elimination. The investigation of the biological properties of EI-1941-1, -2, and -3 and their derivatives disclosed them to be potent and effective ICE inhibitors with less cytotoxicity than EI-1941-1 and -2 in a cultured cell system.