Palladium-catalyzed carboxylative cyclization of propargylic amines with aryl iodides, CO 2 and CO under ambient pressure.

A palladium-catalyzed four-component carboxylative cyclization comprising propargylic amines, aryl iodides, CO 2 and CO was developed. By selecting Et 3 N and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as the base, respectively, both terminal and internal propargylic amines proceeded well facilitated by Pd(PPh 3 ) 2 Cl 2 , affording the functionalized 2-oxazolones in moderate yields. This protocol enlarges the product diversity based on CO 2 conversion and simultaneously provides a cooperative transformation route for both CO 2 and CO.