Direct C3−H Alkylation and Alkenylation of Quinolines with Enones.

Conversion of quinoline C−H bonds into C−C bonds is essential for obtaining the enormous array of derivatives required for pharmaceutical and agrochemical development. Despite over a century of synthetic efforts, direct alkylation and alkenylation at C3−H positions in a wide array of quinoline precursors remain predominantly challenging and elusive. This report outlines the first successful quinoline C3−H alkylation and alkenylation reactions, exhibiting exceptional regio‐ and stereoselectivity, all achieved under redox‐neutral and transition‐metal‐free conditions. The method involves a three‐step, one‐pot or two‐pot sequence, including 1,4‐dearomative addition, functionalization at C3, and elimination or transalkylation to produce 3‐alkylated/alkenylated quinolines. The presence of a carbonyl group in these products allows for further synthetic manipulations, enabling the production of cyanides, amides, amines, and simple alkyl derivatives. [ABSTRACT FROM AUTHOR]