Excellent Catalytic Performances of a Au/C-CuO Binary System in the Selective Oxidation of Benzylamines to Imines under Atmospheric Oxygen.

A green method of the oxidation of benzylamines to imines was developed using a novel binary system of Au/C-CuO. This system was evaluated under atmospheric oxygen, and the corresponding imines were obtained in up to 100% yields by loading 0.006 mol % of Au/C and 1.25 mol % of CuO under mild conditions. This system was also successfully applied to the syntheses of N-containing functional molecules, as well as that of imines on the scale of several grams. Furthermore, the turnover number of the system (more than 8000 times on a gold basis) as well as its ability to be reused more than 10 times for benzylamine oxidation demonstrates the excellent durability and recyclability of the developed system.

Au/Ag/Cu-Mixed Catalysts for the Eco-Friendly Oxidation of 5-Hydroxymethylfurfural and Related Compounds to Carboxylic Acids under Atmospheric Oxygen in Water.

A green method for the oxidation of alcohols to carboxylic acids was developed using a novel co-catalytic system based on gold, silver, and copper catalysts. This reaction system was conducted under atmospheric oxygen in water and mild conditions to selectively oxidize 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid, as a building block for polyethylene furanoate, which is a 100% bio-based, future alternative to the petroleum-based polyethylene terephthalate. Furthermore, various primary alcohols were conveniently oxidized to their corresponding carboxylic acids in up to quantitative yields.

Photoinduced Syntheses and Reactivities of Phosphorus-Containing Interelement Compounds.

The photoinduced reactions of tetraphenyldiphosphine disulfide with a range of organic dichalcogenides successfully afforded a series of phosphorus(V)-chalcogen interelement compounds via a radical process. The relative reactivities of the organic dichalcogenides (i.e., (PhS)2, (PhSe)2, and (PhTe)2) toward the PIII or PV groups in the diphosphine analogues under light were investigated in detail, and a convenient method was developed to form P-S or P-Se interelement compounds from tetraphenyldiphosphine disulfide and (PhS)2 or (PhSe)2 upon photoirradiation. Furthermore, the relative photochemical properties and reactivities of tetraphenyldiphophine (P-P interelement compound) and its analogues toward photoinduced radical addition reactions were also discussed. The formed P-E (E = S, Se) interelement compounds could be utilized for ionic reactions, and they could be transformed into various phosphine reagents via one-pot processes.