A sustainable metal and base-free direct amidation of esters using water as a green solvent.

Herein, we report a simple and efficient synthetic approach for direct amidation of esters C(acyl)-O bond cleavage without any additional reagents or catalysts, using only water as a green solvent. Subsequently, the reaction byproduct is recovered and utilized for the next phase of ester synthesis. This method emphasized metal-free, additive-free, and base-free characteristics making it a new, sustainable, and eco-friendly way to realize direct amide bond formation.

Hydrogen Bond Directed ortho-Selective C-H Borylation of Secondary Aromatic Amides.

Reported is an iridium catalyst for ortho-selective C-H borylation of challenging secondary aromatic amide substrates, and the regioselectivity is controlled by hydrogen-bond interactions. The BAIPy-Ir catalyst forms three hydrogen bonds with the substrate during the crucial activation step, and allows ortho-C-H borylation with high selectivity. The catalyst displays unprecedented ortho selectivities for a wide variety of substrates that differ in electronic and steric properties, and the catalyst tolerates various functional groups.

Nickel-Catalyzed Stereodivergent Synthesis of E- and Z-Alkenes by Hydrogenation of Alkynes.

A convenient protocol for stereodivergent hydrogenation of alkynes to E- and Z-alkenes by using nickel catalysts was developed. Simple Ni(NO ) ⋅6 H O as a catalyst precursor formed active nanoparticles, which were effective for the semihydrogenation of several alkynes with high selectivity for the Z-alkene (Z/E>99:1). Upon addition of specific multidentate ligands (triphos, tetraphos), the resulting molecular catalysts were highly selective for the E-alkene products (E/Z>99:1).

Carbamate Synthesis Using a Shelf-Stable and Renewable C Reactant.

4-Propylcatechol carbonate is a shelf-stable, renewable C reactant. It is easily prepared from renewable 4-propylcatechol (derived from wood) and dimethyl carbonate (derived from CO ) using a reactive distillation system. In this work, the 4-propylcatechol carbonate is used for the two-step synthesis of carbamates under mild reaction conditions.

Selective Hydrogenation of Nitriles to Primary Amines by using a Cobalt Phosphine Catalyst.

A general procedure for the catalytic hydrogenation of nitriles to primary amines by using a non-noble metal-based system is presented. Co(acac) in combination with tris[2-(dicyclohexylphosphino)ethyl]phosphine efficiently catalyzes the selective hydrogenation of a wide range of (hetero)aromatic and aliphatic nitriles to give the corresponding amines.

Efficient Rh-catalyzed C-H borylation of arene derivatives under photochemical conditions.

Photocatalysis allows innovations in organic synthesis. Among the various catalytic reactions, CH-functionalizations offer valuable possibilities for the refinement of easily available building blocks. In this respect, catalytic borylation is of interest, too.

Hindered aryl bromides for regioselective palladium-catalysed direct arylation at less favourable C5-carbon of 3-substituted thiophenes.

The use of the congested aryl bromide 2-bromo-1,3-dichlorobenzene as coupling partner allows to modify the regioselectivity of the arylation of 3-substituted thiophene derivatives in favour of carbon C5. The coupling of this aryl bromide with a variety of 3-substituted thiophenes gave in all cases the desired 5-arylation products in moderate to good yields using only 0.5 mol % of a phosphine-free and air-stable palladium catalyst.

Lewis acid-catalyzed oxidation of benzylamines to benzamides.

A novel Lewis acid-catalyzed oxidation of benzylamines to the corresponding amides has been developed. Using 10 mol% of ZnBr(2) or FeCl(3) as the catalyst and TBHP as the oxidant, amides were produced under mild conditions.

Palladium-catalyzed direct arylation of thiophenes bearing SO2R substituents.

The palladium-catalyzed direct arylation of SO(2)R-substituted thiophene derivatives was found to proceed regioselectively at C5 and in high yields using a variety of aryl bromides and as low as 0.5-0.1 mol % of phosphine-free Pd(OAc)(2) as the catalyst.