Applications Of Palladium-catalyzed Isocyanide Insertion In The Synthesis Of Quinazolin-4(3H)-ones,Aromatic Aldehydes And Aryl Nitriles

As valuable C1 building blocks, isocyanides have been widely explored in organic synthesis due to their flexible nucleophilicity and electrophilicity. In the past decades,transition-metal catalysis, especially palladium-catalyzed reactions involving isocyanide insertion instead of carbon monoxide, has been attracting more attention on the basis of the development of the multicomponent reactions such as Passerini and Ugi reactions. And it offers a vast potential for the synthesis of heterocyclic fine chemicals. The literatures involving palladium-catalyzed isocyanide insertion have been reported, mainly focusing on the imidoylative or carbonylative reactions of different nucleophiles. In addition, the utility of isocyanides as direct CN source has been developed. Herein, this thesis reports palladium-catalyzed coupling of nitrogen and negative hydrogen nucleophiles with isocyanides as C1 building blocks and CN sources.The first part(Chapter 2) centres on the synthesis of quinazolin-4(3H)-ones. It describes a palladium-catalyzed isocyanide insertion coupling of the addition of2-aminobenzamides to get amidines, which leads to desired 4(3H)-quinazolinones after cyclization with losing tert-butylamine. And the method demonstrates the use of isocyanide as C1 building blocks in synthesizing nitrogen-containing heterocycles.The second part(Chapters 3) centres on the synthesis of aromatic aldehydes. The synthesis of aldehydes can be achieved via palladium-catalyzed formylation of aryl halides with isocyanide using silane as hydrogen donor which is different from other carbon,oxygen and nitrogen nucleophiles. And it reveals the utility of isocyanides in carbonylative reactions.The third part(Chapters 4) centres on the synthesis of aryl nitriles.Palladium-catalyzed isocyanide insertion leads to imidoyl-metal-intermediate, which can generate aryl nitriles through losing tert-butyl in the presence of oxidant. That proves isocyanides can be used as CN sources.