Applications Of Isocyanide Insertion In The Synthesis Of Nitrogen-Containing Heterocycles And Nitriles

Since the discovery of the Passerini and Ugi reactions and subsequently related isocyanide-based multicomponent reactions (MCRs), isocyanides have been irreplaceable building blocks in modern organic chemistry. In the past decades, isocyanides act as versatile C1 building blocks instead of carbon monoxide in transition metal-catalyzed reactions which have been attracting more attention. Recently, a new application of isocyanide as a novel cyano source has been reported by some groups, which may further expand the application of isocyanide insertion. The thesis mainly reported the transition metal-catalyzed coupling of carbon and nitrogen nucleophiles with isocyanides to construct C-N bonds.The first part (Chapter 2) centers on the one-step synthesis of benzoxazoles and oxazolines. It describes an efficient ligand-free nickel catalyzed reaction via tert-butyl isocyanide insertion, which demonstrates the use of tert-butyl isocyanide for C-N coupling. Besides, it also reveals that nickel is a highly efficient transition-metal catalyst for isocyanide insertion.The second part (Chapter 2) centers on the synthesis of 4H-benzo[d][1,3]oxazin-4-ones and N-(2-cyanophenyl)benzamides. It describes a novel and useful palladium-catalyzed strategy via tert-butyl isocyanide insertion from readily available N-(2-bromophenyl)benzamides. Treatment of the same imine intermediates with Lewis acid FeCl3 gives 4H-benzo[d][1,3]oxazin-4-ones, whereas with Lewis acid AICl3 delivers N-(2-cyanophenyl)benzamides. It indicates that tert-butyl isocyanide acts not only as a versatile C1 donor, also indirectly as-CN source.