A simple and efficient palladium‐catalyzed carbonylative cyclization of N‐substituted 2‐iodobenzamides and 2‐iodoanilides was investigated for the synthesis of phthalimides and benzoxazinones, respectively, by using phenyl formate as a CO source. The present catalytic protocol circumvents the use of an expensive phosphine ligand as well as solvent in the case of the phthalimide synthesis. Moreover, mild reaction conditions and a tolerance of various functional groups enhance the general applicability of this method.
We report the use of Pd0APTES@K10 (APTES=(3‐aminopropyl)triethoxysilane) as a heterogeneous catalyst for the regioselective synthesis of aurones and flavones from the carbonylative cyclization of 2‐iodophenol with terminal alkynes. This work emphasizes the role of the solvent on the mode of cyclization, that is, 5‐exo or 6‐endo. The 5‐exo products (aurones) were predominant over the 6‐endo products (flavones) in 1,2‐dimethoxyethane (DME), and a reversal of regioselectivity was observed in DMF to favor the 6‐endo product. This protocol provides a simple one‐pot access to a wide variety of aurone and flavone derivatives under mild reaction conditions. The heterogeneous Pd0APTES@K10 catalyst was characterized using several techniques. Furthermore, the catalyst could be reused in up to four consecutive cycles without a significant loss in catalytic activity.
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