A palladium-catalysed enolate alkylation cascade for the formation of adjacent quaternary and tertia

Abstract

The catalytic enantioselective synthesis of densely functionalized organic molecules that contain all-carbon quaternary stereocentres is a challenge to modern chemical methodology. The catalytically controlled, asymmetric α-alkylation of ketones represents another difficult task and is of major interest to our and other research groups. We report here a palladium-catalysed enantioselective process that addresses both problems simultaneously and allows the installation of vicinal all-carbon quaternary and tertiary stereocentres at the α-carbon of a ketone in a single step. This multiple bond-forming process is carried out on readily available β-ketoester starting materials and proceeds by conjugate addition of a palladium enolate, generated in situ, to activated Michael acceptors. As a result, the CO2 moiety of the substrate is displaced by a C–C fragment in an asymmetric cut-and-paste reaction with high yield, diastereomeric ratio and enantiomeric excess. The selective construction of multiple adjacent stereocentres is an important challenge for synthetic organic methodology, and only a handful of catalytic methods exist that can forge adjacent quaternary and tertiary stereocentres. Here, a palladium-catalysed multiple-bond-forming cascade leads to the construction of such systems in high yield, diastereomeric ratio and enantiomeric excess.

Cite this article

Streuff, J., White, D., Virgil, S. et al. A palladium-catalysed enolate alkylation cascade for the formation of adjacent quaternary and tertiary stereocentres. Nature Chem 2, 192–196 (2010). https://doi.org/10.1038/nchem.518

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