Metal-free cross-dehydrogenative coupling of benzimidazoles with aldehydes to N-acylbenzimidazoles

A novel and direct cross-dehydrogenative coupling (CDC) between benzimidazoles with aldehydes promoted by di-tert-butyl peroxide (DTBP) was developed. The reactions generated the corresponding N-acylbenzimidazoles in good yields under metal-free conditions. This method has broad substrate scope and high efficiency.     

Single-step synthesis of idebenone from Coenzyme Q0 via free-radical alkylation under silver catalysis

Idebenone was synthesized directly by free-radical alkylation of 2,3-dimethyl-1,4-benzoquinone (Coenzyme Q₀) with commercially available 11-hydroxyundecanoic acid in the presence of potassium peroxodisulfate and silver nitrate in a mixed solvent (CH₃CN–H₂O, 1:1) under mild condition in good yields (65%, based on Coenzyme Q₀). The reaction is operationally simple and could be used in the preparation of other biologically Coenzyme Q analogues.     

Synthesis of 1-aryl indoles via coupling reaction of indoles and aryl halides catalyzed by CuI/metformin

Ullmann-type C–N coupling reaction has been developed for the synthesis of 1-aryl indole derivatives by indoles and aryl halides in the presence of CuI/metformin (CuI/Met) in DMF. This method is very easy, rapid, and high yielding reaction for the synthesis of 1-aryl indoles. In particular, the metformin, which is used as ligand, is inexpensive and nontoxic that is considered to be relatively environmentally benign.     

One-pot synthesis of dihydropyrano[2,3-c]chromenes via a three component coupling of aromatic aldehydes, malononitrile, and 3-hydroxycoumarin catalyzed by nano-structured ZnO in water: a green protocol

An efficient and green protocol for the synthesis of dihydropyrano[2,3-c]chromene derivatives by one-pot, three component coupling reaction of aromatic aldehyde, malononitrile, and 3-hydroxycoumarin has been developed using nano-structured ZnO as the catalyst. The formation of self-assembled organic nanofiber arising from low-molecular-weight molecules has also been performed. The optical properties of the nano-structured organic molecules were studied.     

Hydroarylation of 2‐Aryloxybut‐1‐en‐3‐ynes via Pd/Acid‐Catalyzed C−H Bond Activation: A Concise Synthesis of 2,3‐Bismethylene‐2,3‐dihydrobenzofurans

An intramolecular exo ‐hydroarylation of 2‐aryloxy‐1,4‐disilylbut‐1‐en‐3‐ynes via ortho ‐C−H bond activation under palladium(0) and acid catalysis was found to give 2,3‐bis(silylmethylidene)‐2,3‐dihydrobenzofurans. The two silyl groups present probably promoted the reaction and played a key role in stabilizing the diene moiety in the product. The products readily led to functionalized condensed cycles by a Diels–Alder reaction.     

An efficient route to 2,3-disubstituted indoles via reductive alkylation using H2 as reductant

An efficient route to 2,3-disubstituted indoles was developed via reductive alkylation of 2-substituted indoles using hydrogen as a clean and atom economic reductant under ambient pressure.