NaI/PPh3-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

A practical NaI/PPh3-catalyzed decarboxylative radical cascade cyclization of N-arylacrylamides with redox-active esters is de-scribed, which is mediated by visible light irradiation. A wide range of substrates bearing different substituents and derived from ubiquitous carboxylic acids, including alpha-amino acids, were synthesized and examined under this very mild, efficient, and cost effec-tive transition-metal-free synthetic method. These afforded various functionalized oxindoles featuring a C3 quaternary stereogenic center. Mechanistic experiments suggest a radical mechanism.

Automated summary

A practical NaI/PPh3-catalyzed decarboxylative radical cascade cyclization of N-arylacrylamides with redox-active esters is reported in this study, which is mediated by visible light irradiation. A wide range of substrates derived from ubiquitous carboxylic acids, including alpha-amino acids, were successfully synthesized under this transition-metal-free and cost-effective synthetic method. The mechanistic experiments suggest a radical mechanism for this reaction.