Palladium‐Catalyzed Carbonylation of Multifunctionalized Substituted Alkynes to Quinolinone Derivatives under Mild Conditions

A highly selective palladium catalyzed carbonylation of 2 alkynylanilines bearing an amide moiety to condensed six membered heterocyclic structures has been developed under mild conditions (room temperature and atmospheric pressure of CO). The carbonylative protocol is also compatible with CO surrogates, such as benzene-1,3,5-triyl triformate (TFBen) or the newly developed calix[6]arenes functionalized with six formate groups (CLX[6]CO), which are both capable to release CO in situ . A series of tricyclic fused heterocycles containing the important oxazino quinolinone scaffold have been selectively obtained ( only the 6 endo dig cyclization mode has been observed ) in good to excellent yields (up to 99%).