Base-mediated C-vinylation of ketones with alkynes: synthesis of β,γ-ethylenic ketones and their synthetic applications

This review summarizes the latest advances in the chemistry of β,γ-ethylenic ketones, which have emerged over the last decade as valuable synthetic building blocks to create molecules of high complexity and diversity. This family of multifunctional γ-aryl-β,γ-ethylenic ketones has now become accessible owing to the discovery and systematic development of a new general C(sp³) – C(sp²) bond-forming reaction, namely superbase-mediated C-vinylation of ketones with alkynes. In the context of the Favorsky reaction (the addition of acetylenic carbanions to the carbonyl group of ketones), this discovery represents a chemical paradox in the form of temperaturecontrolled inversion of electrophilicity and nucleophilicity of acetylenes and ketones. Various transformations of β,γ-ethylenic ketones: nucleophilic addition reactions, inverse-electron-demand Diels–Alder reactions, reactions involving a carbonyl group followed by transformations of functionalized adducts, etc. are discussed. The review also highlights the cascade reactions, in which the in situ formed β,γ-ethylenic ketones, are key intermediates in the synthesis of various highly functionalized carbo- and heterocyclic systems. The bibliography includes 102 references.