Regioselective C-3 Alkylations of Oxindole Dianion

Abstract Oxindole is converted to its dianion by treatment with two equivalents each of n-BuLi and TMEDA. Alkylations with a number of common electrophiles define the scope of synthetically useful transformations leading to 3-monosubstituted and 3,3-disubstituted oxindoles.