Nickel-palladium bimetallic nanoparticles supported on multi-walled carbon nanotubes; versatile catalyst for Sonogashira cross-coupling reactions.

We have developed an efficient method to generate highly active nickel-palladium bimetallic nanoparticles supported on multi-walled carbon nanotubes (Ni-Pd/MWCNTs) by dry mixing of the nickel and palladium salts utilizing the mechanical energy of a ball-mill. These nanoparticles were successfully employed in Sonogashira cross-coupling reactions with a wide array of functionalized aryl halides and terminal alkynes under ligand and copper free conditions using a Monowave 50 heating reactor. Notably, the concentration of palladium can be lowered to a minimum amount of 0.

A palladium-catalysed multicomponent coupling approach to conjugated poly(1,3-dipoles) and polyheterocycles.

Conjugated polymers have emerged over the past several decades as key components for a range of applications, including semiconductors, molecular wires, sensors, light switchable transistors and OLEDs. Nevertheless, the construction of many such polymers, especially highly substituted variants, typically involves a multistep synthesis. This can limit the ability to both access and tune polymer structures for desired properties.

Selective N-chelation-directed C-H activation reactions catalyzed by Pd(II) nanoparticles supported on multiwalled carbon nanotubes.

N-Chelation-directed C-H activation reactions that utilize the Pd(II)/Pd(IV) catalytic cycle have been previously reported. To date, these reactions employ only homogeneous palladium catalysts. The first use of a solid-supported Pd(II) catalyst [Pd(II) nanoparticles on multiwalled carbon nanotubes, Pd(II)/MWCNT] to carry out N-chelation-directed C-H to C-O, C-Cl, and C-Br transformations is reported.

A convergent approach to the total synthesis of telmisartan via a Suzuki cross-coupling reaction between two functionalized benzimidazoles.

A direct and efficient total synthesis has been developed for telmisartan, a widely prescribed treatment for hypertension. This approach brings together two functionalized benzimidazoles using a high-yielding Suzuki reaction that can be catalyzed by either a homogeneous palladium source or graphene-supported palladium nanoparticles. The ability to perform the cross-coupling reaction was facilitated by the regio-controlled preparation of the 2-bromo-1-methylbenzimidazole precursor.

Palladium-catalyzed carbonylative cross-coupling with imines: a multicomponent synthesis of imidazolones.

The palladium-catalyzed coupling of imines, chloroformates, organotin reagents, and carbon monoxide leads to the one-pot formation of ketocarbamates in good yields. These products can further be converted to highly substituted imidazolones via a cyclocondensation reaction. Overall, this methodology provides an alternative approach to imidazolones from five simple and readily available building blocks via a one-pot, multicomponent process.

A direct, one step synthesis of imidazoles from imines and acid chlorides: a palladium catalyzed multicomponent coupling approach.

A palladium-catalyzed one-step synthesis of imidazoles from imines and acid chlorides is described. A plausible mechanism for this multicomponent reaction is provided, which explains the selective incorporation of two different imines into the final product with perfect regiocontrol. Overall, this catalytic process provides a modular method to prepare imidazoles directly from building blocks that are all either commercially available or readily generated.