Transition-Metal-Free Radical Relay Cascade Annulation of Amides: Access to Antitumor Active Benzo[b]azepine and Oxindole Derivatives.

Efficient transition-metal-free synthesis of benzo[b]azepines and oxindoles is achieved via a radical relay cascade strategy employing halogen atom transfer (XAT) for aryl radical generation followed by intramolecular hydrogen atom transfer (HAT). Optimization yielded moderate to substantial yields under visible light irradiation. Preliminary biological assessments revealed promising anti-tumor activity for select compounds.

Photoinduced copper catalyzed nitrogen-to-alkyl radical relay Sonogashira-type coupling of -alkylbenzamides with alkynes.

This report describes a copper-catalyzed, photoinduced -to-alkyl radical relay Sonogashira-type reactions at benzylic sites in -alkylbenzamides with alkynes. The process employs an -to-alkyl radical mechanism, initiated through the copper-catalyzed reductive generation of nitrogen radicals. Radical translocation is facilitated by a 1,5-hydrogen atom transfer (1,5-HAT), leading to the formation of translocated carbon radicals.

Accessing Benzoazepine Derivatives via Photoinduced Radical Relay Formal [5 + 2] Reaction of Amide/Alkyne Enabled by Palladium Catalysis.

A novel class of alkyne-tethered amides facilitates an unprecedented photoinduced palladium-catalyzed radical relay formal [5 + 2] reaction. This innovative strategy allows for the rapid construction of diverse fused benzoazepine structures, yielding structurally novel and compelling compounds. With a broad substrate scope and excellent functional group tolerance, the methodology synthesizes biologically active compounds.

Photoinduced Nitrogen-to-Alkyl Radical Relay Heck Reaction of -Alkylbenzamides with Vinyl Arenes by Palladium Catalysis.

Here, a palladium-catalyzed photoinduced N-to-alkyl radical relay Heck reaction of -alkylbenzamides at benzylic sites with vinyl arenes is described. The reaction employs neither exogeneous photosensitizers nor external oxidants. It is proposed to proceed via a N-to-alkyl hybrid palladium-radical mechanism which occurs under mild conditions that are compatible with a wide range of functional groups.

Aryl-to-alkyl radical relay Heck reaction of amides with vinyl arenes.

A palladium-catalyzed aryl-to-alkyl radical relay Heck reaction of amides at α-C(sp)-H sites with vinyl arenes is described. This process displays a broad substrate scope with respect to both amide and alkene components and provides access to a diverse class of more complex molecules. The reaction is proposed to proceed a hybrid palladium-radical mechanism.