De-Suo Yang

An iodine-promoted Meyer–Schuster rearrangement for the synthesis of α-iodo unsaturated ketones

A facile and efficient iodine-promoted Meyer–Schuster rearrangement of propargyl alcohols for the synthesis of α-iodo-α,β-unsaturated ketones is presented. The reaction is concisely conducted at ambient temperature and shows good functional group tolerance.

An Investigation on the Friction and Wear Properties of Perfluorooctane Sulfonate Ionic Liquids

The study aims to explore the physicochemical and tribological properties of perfluorooctane sulfonate ionic liquids (PSILs) C8F17SO3N4444 and C8F17SO3P4444. The results showed that C8F17SO3P4444 exhibited excellent friction-reducing and anti-wear properties at both room and high temperatures, and C8F17SO3N4444 presented excellent tribological properties at high temperature when they were used as lubricants for steel/steel, steel/copper, and steel/aluminum friction pairs. As compared with traditional fluorine-containing ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl) imide (L-F104), increasing the fluorocarbon chain length of the anion is proven to be an effective way to improve the performance of the PSILs in terms of hydrophobicity, corrosion resistance, and tolerance to extreme pressure, thereby making them more suitable to be used as lubricants under harsh conditions. The X-ray photoelectron spectroscopy analysis indicated that physical adsorption and tribochemical reactions occurred and generated protective films on the sliding surface during the rubbing process, which reduced the friction and elevated the anti-wear efficiency of the PSILs.

K2S2O8/TEMPO-Induced Cascade Oxidative Cyclization/1,2-Migration of Electron-Deficient Groups: Strategy for the Construction of 1H-Pyrrol-2(3H)-ones

A K2S2O8/TEMPO-induced oxidative cyclization of N-unprotected enaminoesters and enaminones that gave 1 H-pyrrol-2(3 H)-ones in good yields with broad functional group compatibility is reported. This method provides easy access to 1,2-carbon migration of ester or acyl group under transition-metal-free conditions.

Synthesis of substituted 2-amino-1,3-oxazoles via copper-catalyzed oxidative cyclization of enamines and N, N-dialkyl formamides

A facile synthesis of 2-amino-1,3-oxazoles via CuI -catalyzed oxidative cyclization of enamines and N,N-dialkyl formamides has been developed. The reaction proceeds through an oxidative C-N bond formation, followed by an intramolecular C(sp2 )-H bond functionalization/C-O cyclization in one pot. This protocol provides direct access to useful 2-amino-1,3-oxazoles and features protecting-group-free nitrogen sources, readily available starting materials, a broad substrate scope and mild reaction conditions.

Regioselective Intermolecular [2 + 2]-Cycloaddition of α-Iodo-Unsaturated Ketones Promoted by Diisobutylaluminum Hydride

The development of intermolecular [2 + 2]-cycloaddition of α-iodo-unsaturated ketones in the presence of diisobutylaluminum hydride (Dibal-H) is reported to produce various trispirocyclic derivatives containing a cyclobutane ring. This sequential lactonization/[2 + 2]-cycloaddition proceeds in high regioselectivity under mild conditions.

Copper-Catalyzed Oxidative Cyclization/1,2-Amino Migration Cascade Reaction

A novel and efficient copper-catalyzed tandem oxidative cyclization/1,2-amino migration of readily available enamino esters for the synthesis of substituted pyrroles has been developed. In this reaction, one C-N bond was cleaved, and two new C-N bonds and one C(sp2)-C(sp2) bond were constructed in one pot. This catalytic system has the obvious advantages of mild reaction conditions and the use of oxygen as the oxidant. The reaction tolerates a wide range of functional groups and is a reliable method for the straightforward synthesis of valuable aminomethyl-substituted pyrroles in good yields.

Biobased Green Lubricants: Physicochemical, Tribological and Toxicological Properties of Fatty Acid Ionic Liquids

ABSTRACT Fatty acid ionic liquids (FAILs) were designed and synthesized by combining quaternary ammonium cations with a range of biobased fatty acid anions. They were found to be good and universal lubricants for steel–steel, steel–copper, and steel–aluminum friction pairs, which possess low corrosivities, moderate viscosity indexes, and thermal stabilities compared to commercially available synthetic oil polyalphaolefin (PAO) 10 and traditional ionic liquid (IL) L-F104. Among them, N1444Oct and N4444Oct were found to have far lower toxicity than L-F104. Investigation of the lubricating mechanism revealed that firm and effective physical adsorption and tribochemical reaction films can be easily formed on the sliding surface due to the polarity of the fatty acid anions and the aliphatic tails, which prevent metal–metal contact and further antiwear and reduce friction.

KI-catalyzed oxidative cyclization of α-keto acids and 2-hydrazinopyridines: efficient one-pot synthesis of 1,2,4-triazolo[4,3-a]pyridines

A one-pot approach to substituted 1,2,4-triazolo[4,3-a]pyridines has been developed that is based on a KI-catalyzed oxidative cyclization of α-keto acids and 2-hydrazinopyridines. This transition-metal-free procedure was highly efficient and shows good economical and environmental advantages.