Copper And Trace Palladium Co-catalyzed Sonogashira Coupling Cyclization To Generate The Reaction Of Indole And Benzofuran

Indoleandbenzo[b]furanareimportantcompoundswhichdisplayawiderange of biological activities and exist in many natural products as a backbone oftheir structural frameworks. Much attention has been paid to synthesizing indolesand benzo[ b ]furan . Up to now, many mathods for making indoles andbenzo[b]furanshavebeenreported,whichinvolvemultistepreactions,aparticularsubstrate,ordisplayunsatisfactoryfunctionalgroupstolerance.Thisthesisfocusesonaconciseandpracticalmethodforthesynthesisofindolesandbenzo[b]furans.Bothheterocyclescouldbeobtainedinhighyieldbythereactions of N‐substituted 2‐iodoanilines or 2‐iodophenol with terminal alkynesundermildconditions,namelyinthepresenceofCuI(10mol%),tracesofpalladium,and a base in EtOH or 1,4‐dioxane without using a phosphine ligand. It is worthnoting that simple aliphatic substituted terminal alkynes could be tolerated tosmoothly produce indole and benzo[b]furan derivatives. Therefore, these methodsare complementary to those of the previously reported Cu‐catalyzedcoupling/cyclization.Inaddition,thisstudyservestofurtherhighlighttheimportanceoftestingfortracemetalimpuritiesinreagents.