Photon-induced regeneration of Pd catalyst for carbonylation of amines to ureas

Abstract

Substituted ureas hold considerable significance in both natural and synthetic chemicals. Pd-based homogenous catalyst has been used for the urea synthesis, however the aggregation of Pd(0) species leads to the deactivation of the catalyst even under mild conditions. Here, we present a photon-involved carbonylation of amines to synthesize ureas, achieving product yields of up to 99%, using Pd(OAc)₂ and KI without losing the performance owing to the fast regeneration of Pd species under light irradiation. Reaction kinetics results and ultraviolet-visible absorption spectra indicate the regeneration of the Pd species is realized by the light irradiation (below 450 nm) which induces the oxidation reaction between HI and O₂ to produce I₂, so that the active species PdI₂ is regenerated through the reaction between Pd(0) and the I₂.