1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride-mediated oxazole rearrangement: Gaining access to a unique marine alkaloid scaffold

Article abstract of DOI:10.1021/jo900264p

Reactions that create a quaternary stereocenter offer a wealth of synthetic utility and are often needed to provide access to the structural diversity of stereocenters found in natural products and biologically important molecules. We have developed a new l-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI)-mediated oxazole rearrangement that affords quaternary 5,5-(aryl, allyl)-substituted hydantoins found in many biologically significant compounds. Furthermore, these quaternary hydantoins can be chemically manipulated to yield the corresponding quaternary imidazolones, which is a unique scaffold found in a compound from the tunicate Dendrodoa grossularia. Herein, we report the scope of this novel rearrangement and the proposed mechanism and showcase its utility through the total synthesis of a marine alkaloid from D. grossularia and two analogues.