Cyclizing Radical Carboiodination,Carbotelluration, and Carboaminoxylation of Aryl Amines

Radical carboiodination of various aryl amines is reported. Aryl diazonium salts, generated in situ from the corresponding aryl amines, are reacted with Bu₄NI to provide the corresponding aryl radicals which undergo 5‐exo or 6‐exo cyclization. Iodine abstraction eventually affords the carboiodinated products in good to excellent yields. If TEMPO is added, the cascade provides the cyclized carboaminoxylation products. Running the reaction in the presence of PhTeTePh affords the phenyltellurated cyclized products.     

Photo‐induced Carboiodination: A Simple Way to Synthesize Functionalized Dihydrobenzofurans and Indolines

Herein, we report a simple, redox‐neutral and pH‐neutral photo‐induced carboiodination reaction under very mild conditions. This protocol employs readily available and cheap aryl bromides and sodium iodide as the starting materials to synthesize valuable functionalized dihydrobenzofurans and indolines in good to excellent yields with broad functional‐group compatibility. As examples to demonstrate the utility of this protocol, gram‐scale reactions and further transformations of the products were accomplished towards the synthesis of bioactive drug candidates. Most significantly, to the best of our knowledge, this reaction represents the first example of a cascade atom‐radical‐transfer addition involving the cleavage of aromatic C?Br bond.     

Additive Effects in the Palladium‐Catalyzed Carboiodination of Chiral N‐Allyl Carboxamides

The use of Pd catalysis as a means to synthesize organic halides has recently received increased attention. Among the reported methods is the Pd‐catalyzed carboiodination, which uses extremely bulky ligands to facilitate carbon–halogen reductive elimination from Pd^II as the key catalytic step. When approaching substrates exhibiting low stereoselectivity, catalyst troubleshooting becomes difficult as there are few ligands known to promote the key reductive elimination. Herein, we present our finding that tertiary amines act as weakly coordinating ligands which significantly enhance diastereoselectivity in the Pd/QPhos‐catalyzed carboiodination of chiral N‐allyl carboxamides. This methodology allows efficient access to enantioenriched and densely functionalized dihydroisoquinolinones, and has been applied toward the asymmetric formal synthesis of (+)‐corynoline.