Iron‐Catalyzed Borrowing Hydrogen C‐Alkylation of Oxindoles Using Alcohols

A general and efficient iron-catalyzed C-alkylation of oxindoles has been developed. This borrowing hydrogen approach employs a (cyclopentadienone)iron carbonyl complex (2 mol %) and exhibits a broad reaction scope, allowing benzylic and simple primary and secondary aliphatic alcohols to be employed as alkylating agents. A variety of oxindoles undergo selective monoC(3)-alkylation in good to excellent isolated yields (28 examples, 50- 92% yield, 79% average yield).