Palladium‐Catalyzed Selective Syntheses of 2,3‐Allenyl Amines via Double Functionalization Coupling of 2‐Alkynyl‐1,4‐diol Dicarbonates

Comprehensive Summary 2,3‐Allenyl amines have shown wide applicability in biomedical and synthetic applications. Due to their enormous potential for applications, researchers have been dedicated to the development of methods for synthesizing 2,3‐allenyl amines. Herein, a palladium‐catalyzed three‐component reaction of 2‐alkynyl‐1,4‐diol dicarbonates, organoboronic acids, and nitrogen nucleophiles forming 2,3‐allenyl amines with excellent regio‐ and chemo‐selectivity has been developed. Substrate compatibility and synthetic applications have been demonstrated. Control experiments supported a mechanism involving 1,2,3‐triene‐Pd species and methylene‐π‐allyl palladium species. Herein, we report a palladium‐catalyzed three‐component reaction of 2‐alkynyl‐1,4‐diol dicarbonates, organoboronic acids, and nitrogen nucleophiles forming 2,3‐allenyl amines. The reaction shows an excellent regio‐ and chemoselectivity and a broad substrate scope. The mechanistic experiments demonstrate an unique β‐O elimilation pathway generating 1,2,3‐triene intermediate.