Selectfluor-Mediated Cascade Lactonization-Selenylation of N-Alkynyl Carbamates

Herein, we have devised a metal-free strategy that enables the efficient synthesis of various 4-selenylated oxazolones via a Selectfluor-mediated cascade lactonization/selenylation of N-alkynyl carbamates. This protocol forges a C-Se bond and a C-O bond while constructing one ring in a single step. The key to success relies on the in situ generation of an electrophilic RSeF species from Selectfluor and diselenides. This method stands out for its extensive substrate scope, high compatibility across diverse functional groups, scalable reaction, and valuable transformations. Mechanistic experiments indicate that a cationic pathway, rather than a radical pathway, is likely involved.