Iron-Catalyzed Cross-Dehydrogenative Coupling.

This review highlights significant advances in iron-catalyzed cross-dehydrogenative coupling (CDC), a method pivotal for forming carbon-carbon (C-C) bonds directly from C-H bonds. This technique uses iron-a naturally abundant, inexpensive, and environmentally benign transition metal-as a catalyst to facilitate the coupling of two unfunctionalized C-H bonds. This method stands out for avoiding pre-functionalized substrates, reducing both waste and cost in organic synthesis. The discussion includes a variety of CDC methodologies involving combinations of C(sp)-H with C(sp)-H, C(sp)-H with C(sp)-H, and C(sp)-H with C(sp)-H bonds. These methods have been successfully applied in synthesizing complex molecules and pharmaceuticals, highlighting the versatility and efficiency of iron catalysis.