Studies On The N-H Cyclization And C-H Arylation Of Anilines

Anilines are an important class of cheap and readily available organic amines.Starting from anilines,various functional compounds such as medicines,pesticides and luminescent materials can be synthesized through the functionalization of C-H bonds and/or N-H bonds and subsequent derivatization.In this paper,two novel reactions are reported: the N-H deoxycyclization of anilines with cyclic ethers under metal-free conditions to synthesize N-aryl substituted nitrogen heterocyclic compounds,the palladium-catalyzed ortho-C-H arylation of unprotected anilines with arylboronic acids to synthesize diaryl compounds.The specific research contents are shown as follows:1.The N-H deoxycyclization of anilines with cyclic ethers promoted by iodine/sodium hypophosphite: Under the transition metal-free reaction conditions,iodine and sodium hypophosphite can promote the N-H deoxyamination of anilines with cyclic ethers,efficiently producing N-aryl substituted N-heterocyclic compounds.Under the optimum reaction conditions,both electron-rich and electron-deficient anilines could react with cyclic ethers to produce the target products in good to high yields.The reaction can be conducted at the gram scale.The products can be further derivatized such as bromination and acetylation.These experimental results demonstrate that this reaction has potential application value in organic synthesis.2.Palladium catalyzed ortho-C-H arylation of unprotected anilines with arylboronic acids: In the presence of iodine,sodium carbonate and lithium chloride,palladium dichloride can catalyze the ortho-C-H arylation of anilines with arylboronic acids to produce the corresponding biaryls.It is worth noting that the unprotected amino group is well tolerated.Under the optimum reaction conditions,both electron-rich and electron-deficient phenylboronic acid can react with anilines to produce the target product in moderate to high yields.The reaction can be performed at the gram scale,and the products can be further derivatized to generate N-aryl substituted biaryls and carbazoles.These experimental results show that the reaction has potential application value in organic synthesis.