Transition-Metal-Free alpha-C-Alkylation of Oxindoles with Alcohols

Transition-metal-free alpha-C-alkylation of oxindoles with alcohols was performed. The reaction requires the presence of LiOtBu and proceeds under thermal conditions. The method exhibits a wide scope of substrates. Both primary and secondary aliphatic and aromatic alcohols can be employed as the alkylating reagents. Oxindole and various 1-alkyl- or 1-aryl-substituted oxindoles can be alkylated. The mechanistic studies show that the reaction may involve both free radical and aldol condensation/MPV processes.