A simple and efficient large-scale synthesis of 3-hydroxyphthalans via oxa-Pictet-Spengler reaction catalyzed by nanosilica sulfuric acid

Nanosilica sulfuric acid is found to be a new, powerful and reusable heterogeneous catalyst for the rapid synthesis of 3-hydroxyphthalans via condensation of aromatic aldehydes and 3-hydroxybenzyl alcohols under conventional heating and microwave irradiation. Scale-up preparation of these heterocycles is also carried out.     

Palladium-catalysed direct arylations of heteroaromatics using more eco-compatible solvents pentan-1-ol or 3-methylbutan-1-ol

The palladium-catalysed direct coupling of aryl halides with heteroaromatics in greener solvents than DMF or DMAc, which are often employed for such couplings, would be a considerable advantage for both industrial application and sustainable development. We observed that a range of aryl bromides undergoe coupling via C-H bond activation/functionalisation reaction of thiazoles or imidazoles in moderate to good yields using pentan-1-ol or 3-methylbutan-1-ol as the solvents. Pentan-1-ol and 3-methylbutan-1-ol are less toxic than DMF or DMAc, moreover they are bioresources as they can be obtained by fermentation. Therefore, these reaction conditions are certainly more eco-compatible than those generally employed for such couplings.     

A new palladium catalyzed protocol for atom-efficient cross-coupling reactions of triarylbismuths with aryl halides and triflates

A new palladium catalyzed protocol for an atom-efficient cross-coupling reaction of triarylbismuths with aryl halides and triflates has been described. The palladium catalytic system with Cs₂CO₃ base was found to be very efficient in DMA solvent to furnish excellent yields of cross-coupled functionalized biaryls in short reaction times.     

Pd-catalyzed direct arylation of 3-fluorofurans utilizing the neighboring effect of fluorine atom: facile synthesis of tetrasubstituted monofluoro furans

Pd-catalyzed direct arylation of 3-fluorofurans with a variety of aryl bromides was facilitated by the neighboring effect of fluorine atom to provide tetrasubstituted monofluoro furans in moderate to good yields.     

A new one-pot neat synthesis of 1,2,4-triazol-3-ones through 4-（N,N-dimethylamino） pyridine （DMAP） catalyzed cyclocondensation of ethyl carbazate with aryl nitriles

A new one-pot neat synthesis of some 5-aryl-2,4-dihydro-3H- 1,2,4-triazol-3-ones through cyclocondensation of ethyl carbazate with aryl nitriles catalyzed by DMAP as an efficient and basic nucleophilic catalyst is described.     

Palladium β-diketonate complex catalyzed synthesis of monosubstituted arylferrocenes

Palladium β-diketonate complexes are reported as efficient catalysts for the selective synthesis of monosubstituted arylferrocenes by a cross-coupling reaction of bis(ferrocenyl)mercury with aryl halides. The present protocol was applicable to aryl halides providing good to excellent yields of the desired products.     

Desulfinylative Pd-catalyzed coupling reaction of arenediazonium salt with aryl sulfinates to give unsymmetrical biaryls

An efficient route for the synthesis of unsymmetrical biaryls was developed via palladium catalyzed reaction of arenediazonium salts and aryl sulfinates under inert atmosphere. This synthesis involves cascade processes. Tetrabutylammonium iodide was used as an iodide source for in situ formation of aryl iodide, followed by desulfinylative cross-coupling reaction between aryl sulfinates and aryl iodides. A wide range of biaryls were selectively prepared in one pot from simple substrates in good to excellent yields.     

Synthesis of N‐alkyl‐N′‐aryl or Alkenylpiperazines: A Copper‐Catalyzed C–N Cross‐Coupling in the Presence of Aryl and Alkenyl Triflates and DABCO

Unsymmetrical piperazines are key constituents of many pharmaceuticals. Given that the selective introduction of an aryl and alkyl motif onto the piperazine is not always straightforward, direct arylation and alkenylation of 1,4‐diaza‐bicyclo[2.2.2]octane would obviate the inefficiencies associated with the preparation of these target molecules. We have utilized alkyl halides, aryl or alkenyl triflates, and 1,4‐diaza‐bicyclo[2.2.2]octane for the synthesis of N‐alkyl‐N ′‐aryl or alkenylpiperazines. The optimum conditions are developed using CuCl, t‐BuOL i in NMP . Alkenyl triflates requires N ,N ′‐dimethylethylenediamine and higher temperature to afford the desired cross‐coupled product. Substrates bearing electron‐deficient and electron‐rich groups were successfully coupled under the optimum reaction conditions.     

Suzuki-Miyaura cross-coupling reaction of aryl chlorides with aryl boronic acids catalyzed by a palladium dichloride adduct of N-diphenylphosphanyl-2-aminopyridine

One palladium dichloride adduct of a phosphine-pyridine ligand N-diphenylphosphanyl-2-aminopyridine (L₁) [(L₁)PdCl₂] (1) has been prepared and structurally characterized. Compound 1 can be used as an effective catalyst for the Suzuki-Miyaura cross-coupling reactions of unreactive aryl chlorides with aryl boronic acids, and worked much better than its mono- or bidentate phosphine ligands. The reactions with a wide scope of substrates proceeded to give desired products in good to excellent yields.