A good combination between a continuously irradiating microwave system and recyclable Ru(0) nanoparticle for ligand-free Suzuki–Miyaura coupling.

Self-assembled multilayer iron(0) nanoparticles (NPs, 6–10 nm), namely, sulfur-modified Au-supported Fe(0) [SAFe(0)], were developed for ligand-free one-pot carbon–carbon/carbon–nitrogen bond-forming reactions. SAFe(0) was successfully prepared using a well-established metal–nanoparticle catalyst preparative protocol by simultaneous in situ metal NP and nanospace organization (PSSO) with 1,4-bis­(trimethylsilyl)-1,4-dihydropyrazine (Si-DHP) as a strong reducing agent. SAFe(0) was easy to handle in air and could be recycled with a low iron-leaching rate in reaction cycles.

A nanoparticle (NP)-based precatalyst has been developed for organic synthesis: sulfur-modified Au-supported Fe (SAFe). The SAFe was easily prepared through a three-step procedure involving simultaneous in situ metal NP and nanospace organization (PSSO). This method avoids the need for preformed templates for immobilizing and stabilizing the metal nanoparticles. On account of the relative safety and enormous earth abundance of iron, SAFe potentially represents an ideal precatalyst for carbon–carbon bond-forming cross-coupling reactions. As such, it has been applied as a precatalyst to Kumada coupling under ligand-free conditions, proving to be capable of being recycled and used repeatedly for this reaction. Analysis of SAFe and of reaction mixtures suggested that the active species in these reactions are produced in situ by assemblies of iron-based NPs.

We have developed a continuous microwave irradiation-assisted Buchwald¬–Hartwig amination using our original Pd nanoparticle catalyst with copper plate as a co-existing metal solid. In this methodology, a microwave-controlled chemoselectivity was...