Photoelectrocatalytic XAT strategy for the generation of alkyl radicals to synthesize alkylated 3-CF3-2-oxindoles

Abstract

An organocatalyzed photoelectrochemical strategy for the generation of alkyl radicals from alkyl bromides and iodides through a halogen atom transfer (XAT) process has been developed. These alkyl radicals are used in radical tandem cyclization with N-aryl-2-(trifluoromethyl)acrylamides to access alkylated 3-CF3-2-oxindoles. This approach employs 9,10-phenanthrenequinone (PQ) as the catalyst and (TMS)3SiOH as the XAT reagent, eliminating the requirement for metal-reagents and oxidants. The reactions incorporate photocatalysis, electrochemistry and halogen atom transfer, demonstrating remarkable compatibility with a diverse array of primary, secondary, and tertiary alkyl bromides and iodides.