The ligand- and copper-free Sonogashira reaction of (Het)aryl halides (Br and Cl) with various terminal alkynes and the Heck coupling of (Het)aryl halides (Br and Cl) with a series of olefins, catalyzed by palladium nanoparticles supported on newly generated Al(OH)3, were developed. The catalyst can be readily recovered and reused 6 times without significant loss of activity and palladium leaching.

An efficient ligand-free Pd(OAc)2-catalyzed selective arylation of pyridine N-oxides using potassium (hetero)aryltrifluoroborates as coupling partners via C–H bond activation was achieved in the presence of TBAI. This approach has a broad substrate scope and shows moderate to high yields.

A ligand-free Pd/Al(OH)3 nano-catalyst which is prepared by one-pot three-component method using Pd(PPh3)4, tetra (ethylene glycol), and aluminum tri-sec-butoxide exhibits excellent catalytic activity in Stille cross-couplings of (Het)aryl chlorides, arenediazonium tetrafluoroborate salts with phenyltributylstannane, respectively, and Kumada couplings of (Het)aryl chlorides with various Grignard reagents. More importantly, these two processes show excellent functional group compatibility with moderate to good yields and they are also versatile with respect to not only (Het)aryl chlorides, but also diazonium salts, and heteroaryl Grignard reagents. The nano-catalyst could also be recycled and reused 5 times without loss of activity and decrease of yield.

Palladium nanoparticles supported on newly generated Al(OH)3 was found to be a highly efficient catalyst in oxidative homo-couplings of (Het)aryl alkynes, (Het)arylboronic acids and potassium (Het)aryltrifluoroborates, respectively. Moderate to excellent yields of symmetrical 1,3-diynes and biaryls were obtained under mild conditions.

Tetrabutylammonium bromide (TBAB) was found to be a highly effective catalyst at as low as 10 mol% for regioselective ring opening of a variety of N-tosylaziridines with various carboxylic acids to afford the corresponding ring-opening products (derived β-amino esters) in good to excellent yields and up to 100% regioselectivity in combination with DMF as the solvent.

Suzuki–Miyaura cross-couplings of arenediazonium salts with arylboronic acids catalyzed by highly active aluminium hydroxide-supported palladium nanoparticles catalyst have been investigated for the first time. The reactions are performed at 25 °C in MeOH without any base and ligand to afford biaryls in good to excellent yields under non-anhydrous and non-degassed conditions.

A simple and efficient method has been developed which describes KOH-oriented catalytic regioselective ring-opening reactions of various N-tosylaziridines with malonates. In the presence of 20 mol% KOH, most N-tosylaziridines can smoothly react with malonates to give the corresponding products in good to excellent yields (up to 99%) and with good to excellent regioselectivity under mild experimental conditions.Graphical abstractKOH-catalyzed regioselective ring-opening reactions of various N-tosylaziridines with malonates have been developed. In the presence of 20 mol% KOH, most N-tosylaziridines can smoothly react with malonates to give the corresponding products in good yields and with good regioselectivity under mild conditions.Highlights► This manuscript reported inorganic base-catalyzed ring-opening reactions of N-tosylaziridines with malonates for the first time. ► It is found that KOH was an efficient and mild catalyst for the desired ring-opening reactions. ► Good to excellent yields have been provided for a wide variety of N-tosylaziridines and malonates. ► Good to high regioselectivity are obtained in terms of most N-tosylaziridines under mild reaction conditions.

Suzuki–Miyaura cross-couplings of arenediazonium salts with arylboronic acids catalyzed by highly active aluminium hydroxide-supported palladium nanoparticles catalyst have been investigated for the first time. The reactions are performed at 25 °C in MeOH without any base and ligand to afford biaryls in good to excellent yields under non-anhydrous and non-degassed conditions.

An efficient ligand-free Pd(OAc)2-catalyzed selective arylation of pyridine N-oxides using potassium (hetero)aryltrifluoroborates as coupling partners via C–H bond activation was achieved in the presence of TBAI. This approach has a broad substrate scope and shows moderate to high yields.