Metal-Free Decarboxylative Allylation of Oxime Esters under Light Irradiation

Allylation reactions, often used as a key step for constructing complex molecules and drug candidates, typically rely on transition-metal (TM) catalysts. Even though TM-free radical allylations have been developed using allyl-stannanes, -sulfides, -silanes or -sulfones, much less procedures have been reported using simple and commercially available allyl halides, that are used for the preparation of the before-mentioned allyl derivatives. Here, we present a straightforward photocatalytic protocol for the decarboxylative allylation of oxime esters using allyl bromide derivatives under metal-free and mild conditions. This methodology yields a diverse variety of functionalized molecules including several pharmaceutically relevant molecules. An effective and general photocatalyzed allylation reaction has been established. This transformation that uses simple allyl bromides and oxime esters derived from commercially available and pharmaceutically relevant carboxylic acids, gives access to a wide array of allylic compounds that can be further employed in organic synthesis. image