Reactions O(P, D) + HCCCN(XΣ) (Cyanoacetylene): Crossed-Beam and Theoretical Studies and Implications for the Chemistry of Extraterrestrial Environments.

Cyanoacetylene HCCCN), the first member of the cyanopolyyne family (HCN, where = 3, 5, 7, ...

C(sp )-H Arylation Promoted by a Heterogeneous Palladium-N-Heterocyclic Carbene Complex in Batch and Continuous Flow.

A heterogeneous reusable palladium(II)-bis(N-heterocyclic carbene) catalyst was prepared and shown to catalyze the intramolecular C(sp )-H activation/cyclization of N-alkyl-2-bromoanilines furnishing indolines. This new catalytic system was based on a bis-imidazolium ligand immobilized on a spaced cross-linked polystyrene support. The iodide ligands on the catalyst played a central role in the efficiency of the process occurring through a "release and catch" mechanism.

A Waste-Minimized Approach to Cassar-Heck Reaction Based on POLITAG-Pd Heterogeneous Catalyst and Recoverable Acetonitrile Azeotrope.

Three different Pd -based heterogeneous catalysts were developed and tested in the Cassar-Heck reaction (i. e., copper-free Sonogashira reaction) aiming at the definition of a waste minimized protocol.

Reusable Pd@PEG Catalyst for Aerobic Dehydrogenative C-H/C-H Arylations of 1,2,3-Triazoles.

Dehydrogenative C-H arylations of 1,2,3-triazoles were accomplished with the aid of a reusable palladium catalyst in PEG. The widely applicable oxidative palladium catalysis enabled the synthesis of fully decorated 1,2,3-triazoles with a broad functional-group tolerance and ample substrate scope. The sustainability of the aerobic C-H arylation was reflected by the use of PEG as green reaction medium and demonstrated by recycling studies of the catalyst and the reaction medium.

C-H functionalization reactions under flow conditions.

C-H functionalization technologies have progressed enormously in the last decade as testified by the great number of publications that have appeared in the literature, which are receiving great attention from researchers from different areas of expertise. While most of the protocols reported realize the C-H functionalization processes under batch conditions, there is a growing interest in the development of continuous-flow procedures aiming at increasing the performances of established methodologies or the definition of otherwise unfeasible transformations. This review summarizes the application of flow technologies for the realization of C-H functionalization reactions.

Polarclean as a Sustainable Reaction Medium for the Waste Minimized Synthesis of Heterocyclic Compounds.

Herein we report the use of Rhodiasolv Polarclean as a novel polar aprotic solvent for the synthesis of decorated heterocycles via dipolar cycloaddition (isooxazoles) or intramolecular C-H functionalization processes (benzo-fused chromenes). The use of Polarclean allowed to isolate the final products in good yields by simple solid filtration or liquid-liquid phase separation, avoiding the need for chromatographic purification. Moreover, since in the synthesis of benzo-fused chromenes, the metal catalyst is retained in Polarclean, the catalyst/reaction medium can be easily reused for consecutive reaction runs, without any apparent loss in efficiency.

Sustainable Protocol for the Reduction of Nitroarenes by Heterogeneous Au@SBA-15 with NaBH under Flow Conditions.

A gold-incorporated SBA-15 catalyst was prepared by a solvent-free ball-milling approach. The catalyst showed high reactivity and selectivity in the reduction of a variety of nitroarenes to anilines operating in absolute EtOH with NaBH as reducing agent. The catalyst was reused in batch conditions over five consecutive runs without any losses of activity or selectivity.

Avoiding hot-spots in Microwave-assisted Pd/C catalysed reactions by using the biomass derived solvent γ-Valerolactone.

Herein, we report the use of γ-valerolactone as a new biomass-derived reaction medium for microwave assisted organic synthesis. The interaction of this solvent with microwaves and its heating profile under microwave irradiation has been fully characterized for the first time, demonstrating its stability and the applicability in microwave assisted Pd/C catalysed reactions avoiding the arcing phenomena frequently observed in these conditions. The use of γ-valerolactone demonstrated to be compatible with aliphatic and aromatic amines in the hydrogen transfer Pd/C mediated synthesis of benzimidazoles.

C-H arylations of 1,2,3-triazoles by reusable heterogeneous palladium catalysts in biomass-derived γ-valerolactone.

C-H arylations were accomplished with a user-friendly heterogeneous palladium catalyst in the biomass-derived γ-valerolactone (GVL) as an environmentally-benign reaction medium. The user-friendly protocol was characterized by ample substrate scope and high functional group tolerance in the C-H arylation of 1,2,3-triazoles, and the palladium catalyst could be recycled and reused in the C-H activation process.

A Catalytic Peterson-like Synthesis of Alkenyl Nitriles.

A heterogeneous fluoride catalyst was found to enable the straightforward formation of alkenyl nitriles from the reaction of aldehydes and simple or substituted acetonitriles, in the presence of commercially available silazanes and in solvent-free conditions. The protocol afforded the products in good to excellent yields with selectivity values dependent on the nature of the substrates. It represents an alternative to classic approaches using stoichiometric strong bases, and the catalyst can be easily recovered and reused for consecutive cycles.