N‐Heterocyclic Carbene‐Palladium Complex Catalyzed Oxidative Carbonylation of Amines to Ureas

Abstract

Palladium carbene shows high efficiency without any promoter on oxidative carbonylation of amines to ureas and a new type of palladium carbene complex containing both an aniline and an NHC ligands was found to be the active species for the reaction.

N-Heterocyclic Carbenes in Late Transition Metal Catalysis

“…Alternatively, [(NHC)Pd]-based systems can catalyze the oxidative carbonylation of amines to ureas . In this case, no cocatalyst was required and the reactions were carried out in DMF at 150 °C for anilines or in diglyme at 100 °C for aliphatic amines (eq ).…”

Easily prepared water soluble Pd-NHC complex as an efficient, phosphine-free palladium catalyst for the Sonogashira reaction

“…Recently, Plenio's group [17,18], using sulfonated water-soluble ligands and complexes as catalyst were successful with some cross-coupling reactions with water as the solvent. Inspired by these results and in connection with our interests in the development of a new Pd-NHC (NHC: N-Heterocyclic Carbene) catalytic system for the cross coupling [16,[19][20][21][22][23][24], we here describe a water soluble phosphine-free Pd-NHC/H2O catalytic system that is efficient for the Sonogashira coupling reaction of alkynes and aryl iodides (Scheme 1). It gave a series of diarylalkynes in one-pot synthesis under mild conditions.…”

NHC‐Pd complex‐catalyzed double carbonylation of aryl iodides with secondary amines to α‐keto amides

“…Various metal–NHC complexes have found widespread use in homogeneous catalysis, such as Ru‐NHC complex‐catalyzed olefin metathesis and other chemical transformations, Pd‐NHC complex‐catalyzed cross‐coupling reactions and some Pd or Rh NHC–complex‐mediated carbonylation reactions . As a part of our ongoing project to extend the scope of the use of metal–NHC complex in carbonylation reactions, we report herein a Pd‐NHC catalytic system for the double carbonylation of aryl iodides with secondary amines to α‐keto amides (Scheme ).…”