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

Graphical Transition-metal-free reaction of oxindoles with primary or secondary alcohols in the presence of LiO t Bu affords α-C-alkylated oxindoles. Transition-metal-free α-C-alkylation of oxindoles with alcohols was performed. The reaction requires the presence of LiO t Bu 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.