Ascorbic Acid-Initiated Tandem Radical Cyclization of N-Arylacrylamides to Give 33-Disubstituted Oxindoles

摘要

An ascorbic acid-promoted and metal-free tandem room temperature cyclization of N-arylacrylamides with 4-nitrobenzenediazonium generated in situ was developed. This reaction proceeds smoothly through a radical mechanism and provides an environmentally friendly alternative approach to biologically active 3-alkyl-3-benzyloxindoles, avoiding the use of excess oxidants and light irradiation.