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Electroreductive Olefin-Ketone Coupling.

ABSTRACT: A user-friendly approach is presented to sidestep the venerable Grignard addition to unactivated ketones to access tertiary alcohols by reversing the polarity of the disconnection. In this work a ketone instead acts as a nucleophile when adding to simple unactivated olefins to accomplish the same overall transformation. The scope of this coupling is broad as enabled using an electrochemical approach, and the reaction is scalable, chemoselective, and requires no precaution to exclude air or water. Multiple applications demonstrate the simplifying nature of the reaction on multistep synthesis, and mechanistic studies point to an intuitive mechanism reminiscent of other chemical reductants such as SmI₂ (which cannot accomplish the same reaction).

SUBMITTER: Hu P

PROVIDER: S-EPMC8353665 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Ketone-Olefin Coupling of Aliphatic and Aromatic Carbonyls Catalyzed by Excited-State Acridine Radicals.

Project description:Ketone-olefin coupling reactions are common methods for the formation of carbon-carbon bonds. This reaction class typically requires stoichiometric or super stoichiometric quantities of metal reductants, and catalytic variations are limited in application. Photoredox catalysis has offered an alternative method toward ketone-olefin coupling reactions, although most methods are limited in scope to easily reducible aromatic carbonyl compounds. Herein, we describe a mild, metal-free ketone-olefin coupling reaction using an excited-state acridine radical super reductant as a photoredox catalyst. We demonstrate both intramolecular and intermolecular ketone-olefin couplings of aliphatic and aromatic ketones and aldehydes. Mechanistic evidence is also presented supporting an "olefin first" ketone-olefin coupling mechanism.

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Construction of bicyclic ring systems via a transannular SmI2-mediated ketone-olefin cyclization strategy.

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