Radical Changes in Lewis Acid Catalysis: Matching Metal and Substrate

Abstract

Whereas the stereochemical rigidity of the coordination sphere of boxmi/Cu II catalysts is key to achieving high enantioselectivity in the electrophilic alkylation of b-ketoesters, this pathway is outperformed by ar adical process for the corresponding catalytic transformation of oxindoles,g iving rise to racemic products.F or the corresponding Zn II catalysts, the selectivity in the latter process is outstanding despite the greater plasticity of the coordination shell. This reaction was thus developed into ah ighly useful synthetic method, which enabled the conversion of wide range of substrates with high yields and enantioselectivities.

Cross‐Coupling Reaction of Dimer‐Derived Persistent Tertiary‐Carbon‐Centered Radicals with Azo Compounds

“…However, although there has been significant progress, the dynamic structural changes of such dimers having an elongated C–C bond in the solution state are not yet well understood . Furthermore, the potential utility of the dimers as precursors of persistent radicals in cross‐coupling reactions has scarcely been studied, even though the persistent radical effect is widely recognized . Here, we report our structural analyses of the behavior of dimers derived from 2‐oxindoles and benzofuranones in the solution state, which provided a basis for us to broaden the substrate scope of the cross‐coupling reaction.…”

Cyanomethylation of Substituted Fluorenes and Oxindoles with Alkyl Nitriles

“…The asymmetric cyanomethylenation of three-substituted oxindoles using prefunctionalized cyanomethyl halides has been reported by different groups (Scheme a) . Recently, many studies focused on the atom-transfer radical addition reactions of nitriles with olefins .…”