Iron‐Catalyzed Borrowing Hydrogen
<i>C</i>
‐Alkylation of Oxindoles with Alcohols
作者:Mubarak B. Dambatta、Kurt Polidano、Alexander D. Northey、Jonathan M. J. Williams、Louis C. Morrill
DOI:10.1002/cssc.201900799
日期:——
general and efficient iron‐catalyzed C‐alkylation of oxindoles has been developed. This borrowing hydrogen approach employing a (cyclopentadienone)iron carbonyl complex (2 mol %) exhibited a broad reaction scope, allowing benzylic and simple primary and secondary aliphatic alcohols to be employed as alkylating agents. A variety of oxindoles underwent selective mono‐C3‐alkylation in good‐to‐excellent
Oxindoles have been successfully alpha-alkylated under Cp*Co-III catalysis by a vast array of secondary alcohols, including cyclic, acyclic, symmetrical, and unsymmetrical, to produce C-alkylated oxindoles. This protocol was also extended to the alpha-alkylation of N,N-dimethyl barbituric acid and benzyl cyanides. The kinetic profile and other preliminary mechanistic investigations suggest a first-order reaction rate in oxindoles and catalysts. A plausible catalytic cycle is proposed on the basis of the kinetic profile, of other preliminary mechanistic investigations, and of previous mechanistic studies on similar transformations, whereas density functional theory calculations provide insight into the nature of the active species.
Manganese-Catalyzed C(α)-Alkylation of Oxindoles with Secondary Alcohols via Borrowing Hydrogen