DAST-Mediated Cyclization of α,α-Disubstituted-α-acylaminoketones: Efficient and Divergent Synthesis of Unprecedented Heterocycles

The design of a new potent nonsteroidal ecdysone agonist led to the discovery of a diethylaminosulfur trifluoride (DAST)-mediated cyclization of α,α-disubstituted-α-acylaminoketones. The resulting fluorooxazolines can be ring-opened or selectively substituted by a range of nucleophiles to provide in high yields a diverse array of unprecedented heterocyclic frameworks.