Metal-free halogen atom transfer for carbocyclization of N-arylacrylamides enabled by visible light-excited ligated boryl radicals

Abstract

A visible light-induced, metal-free method for synthesizing 3,3-dialkylated oxindoles via boryl radical-mediated halogen atom transfer is described. This approach enables the carbocyclization of N-arylacrylamides under ambient air using an organic photosensitizer and NHC-BH₃, to accommodate both alkyl and aryl halides. The practicality of this protocol is demonstrated through facile scalability and applications in drug synthesis.