Substituent-Determined Intramolecular Hydrogen Transfer for Photopromoted Intermolecular Cycloaddition of Anthraquinones with Aryl Olefins.

The formation of intramolecular hydrogen bonds in anthraquinones makes them inert to photoinduced reactions; therefore, it is a great challenge to phototransform these compounds. Herein, we reported a formal visible-light-induced [4 + 2] cycloaddition of both 1-hydroxyanthraquinones and 1-aminoanthraquinones with olefins under external photocatalyst-free conditions with high regioselectivity. More than 60 substrates are disclosed, demonstrating the reliability of this protocol to construct diverse functionalized anthraquinone derivatives.

Oxidation of Enones for Regioselective [3+2] Cycloaddition through γ-Enone Radical Intermediates.

Invited for the cover of this issue is the group of Min Zhang and Weiping Su at the Fujian Institute of Research on the Structure of Matter. Read the full text of the article at 10.1002/chem.201903551.

Oxidation of Enones for Regioselective [3+2] Cycloaddition through γ-Enone Radical Intermediates.

Herein, an oxidization reaction of enones with a CuII complex that leads to a new type of regioselective [3+2] cycloaddition is reported. Highly functionalized cyclopentenes and spirocyclic compounds are obtained in moderate-to-good yields. This cycloaddition reaction occurred through the formation of γ-enone radicals, providing a rarely explored reactivity pattern for enones.