α,α‐Dichlorination of Oxindole Derivatives Using (Dichloroiodo)benzene

Abstract

Abstract Use of the hypervalent aryl‐λ 3 ‐iodane reagent iodobenzene dichloride (PhICl 2 ) in the α‐carbonyl dichlorination of 2‐oxindoles is reported. Treating a series of diversely substituted 3‐diazo‐2‐oxindoles with PhICl 2 in the presence of pyridine, a Lewis base iodane‐activator, results in 3,3‐dichloro‐2‐oxindole products. Activation of PhICl 2 is key to the chlorination proceeding rapidly, chemoselectively and in good to excellent yields. This investigation represents a novel approach to the synthesis of 3,3‐disubstituted‐2‐oxindoles, and illustrates the compatibility of the ligand‐transfer reaction with the 2‐oxindole scaffold. magnified image