Novel bis(oxazole) pincer ligands for catalysis: Application in Suzuki-Miyaura cross coupling reactions under aerobic conditions

Metal-free iodine(iii)-promoted synthesis of 2,5-diaryloxazoles

A nonmetal-catalyzed oxidative cyclization to achieve 2,5-disubstituted oxazoles from inexpensive and readily available substituted chalcone, (diacetoxyiodo)benzene (PIDA) and ammonium acetate (NH4OAc) at room temperature is described. The reaction forms a variety of 2,5-diaryloxazoles in good to excellent yields with broad substrate scope under mild conditions without the requirement of ligands and additional bases.

A new hierarchically porous Pd@HSQ monolithic catalyst for Mizoroki–Heck cross-coupling reactions

Palladium nanoparticles are embedded in hierarchically porous hydrogen silsesquioxane monoliths by on-site reduction to prepare a reusable catalyst for Mizoroki–Heck reactions.

[2,6-Bis(5-ethoxy-1,3-oxazol-2-yl)-4-methoxyphenyl-κ3N,C1,N′]bromidopalladium(II)

In the title compound, [PdBr(C₁₇H₁₇N₂O₅)], the Pd^II atom is coordinated by an N,C¹,N′-tridentate pincer ligand and a Br atom in a distorted square-planar geometry. In the crystal, mol­ecules are connected by C—H⋯Br and C—H⋯O hydrogen bonds, and π–π inter­actions between the oxazole and benzene rings [centroid–centroid distance = 3.7344 (19) Å], resulting in a three-dimensional supra­molecular structure.

Room temperature copper(II)-catalyzed oxidative cyclization of enamides to 2,5-disubstituted oxazoles via vinylic C-H functionalization

A copper(II)-catalyzed oxidative cyclization of enamides to oxazoles via vinylic C-H bond functionalization at room temperature is described. Various 2,5-disubstituted oxazoles bearing aryl, vinyl, alkyl, and heteroaryl substituents could be synthesized in moderate to high yields. This reaction protocol is complementary to our previously reported iodine-mediated cyclization of enamides to afford 2,4,5-trisubstituted oxazoles.

N,N,N,N-Tetra-kis(2-chloro-ethyl)-3,4-dimethyl-thio-phene-2,5-dicarboxamide

In the title compound, C(16)H(22)Cl(4)N(2)O(2)S, the two imide groups adopt a trans arrangement relative to the central thienyl ring, so the four terminal 2-chloro-ethyl arms adopt different orientations. In the crystal, mol-ecules are linked by weak C-H⋯Cl and C-H⋯O hydrogen bonds into a three-dimensional network.

In Situ Generation of Palladium Nanoparticles: A Simple and Highly Active Protocol for Oxygen-Promoted Ligand-Free Suzuki Coupling Reaction of Aryl Chlorides

An oxygen-promoted ligand-free Suzuki coupling reaction catalyzed by in situ generated palladium nanoparticles in PEG-400 under aerobic conditions has been demonstrated. The reaction was highly efficient for coupling aryl chlorides with phenylboronic acid in short times under mild conditions.