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
Transition-metal-catalyzed Electrophilic Activation of 1,1-Difluoro-1-alkenes: Oxindole Synthesis via Intramolecular Amination
作者:Hiroyuki Tanabe、Junji Ichikawa
DOI:10.1246/cl.2010.248
日期:2010.3.5
In the presence of a catalytic amount of palladium(II) chloride, β,β-difluorostyrenes bearing a sulfonamido group at the ortho position were treated with trimethylsilyl trifluoromethanesulfonate to afford oxindoles in high yield. The reactions proceeded via 5-endo-trig cyclization, hydrolysis, and desulfonylation. This sequence allowed the transformation of difluorostyrenes into free oxindoles in a one-pot operation.