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Fluorine-containing moieties show significant effects in improving the properties of functional molecules. Consequently, efficient methods for installing them into target compounds are in great demand, especially those enabled by metal-free catalysis. Here we show a diazaphospholene-catalyzed hydrodefluorination of trifluoromethylalkenes to chemoselectively construct gem-difluoroalkenes and terminal monofluoroalkenes by simple adjustment of the reactant stoichiometry. This metal-free hydrodefluorination features mild reaction conditions, good group compatibility, and almost quantitative yields for both product types. Stoichiometric experiments indicated a stepwise mechanism: hydridic addition to fluoroalkenes and subsequent β-F elimination from hydrophosphination intermediates. Density functional theory calculations disclosed the origin of chemoselectivity, regioselectivity and stereoselectivity, suggesting an electron-donating effect of the alkene-terminal fluorine atom. Fluorine-containing moieties show significant effects in improving the properties of functional molecules. Here the authors show diazaphospholene-catalyzed hydrodefluorination of trifluoromethylalkenes to chemoselectively construct gem-difluoroalkenes and terminal monofluoroalkenes by simple adjustment of the reactant stoichiometry. [ABSTRACT FROM AUTHOR]

The discovery of modern medicine relies on the sustainable development of synthetic methodologies to meet the needs associated with drug molecular design. Heterocycles containing difluoromethyl groups are an emerging but scarcely investigated class of organofluoro molecules with potential applications in pharmaceutical, agricultural and material science. Herein, we developed an organophotocatalytic direct difluoromethylation of heterocycles using O2 as a green oxidant. The C–H oxidative difluoromethylation obviates the need for pre-functionalization of the substrates, metals and additives. The operationally straightforward method enriches the efficient synthesis of many difluoromethylated heterocycles in moderate to excellent yields. The direct difluoromethylation of pharmaceutical moleculars demonstrates the practicability of this methodology to late-stage drug development. Moreover, 2′-deoxy-5-difluoromethyluridine (F2TDR) exhibits promising activity against some cancer cell lines, indicating that the difluoromethylation methodology might provide assistance for drug discovery. Heterocycles containing difluoromethyl groups are molecules with potential application in pharmaceutical, agricultural and materials science. Here, the authors show an organophotocatalytic difluoromethylation of heterocycles using O2 as green oxidant and preliminarily study the products' bioactivity. [ABSTRACT FROM AUTHOR]

The past decade has witnessed a booming growth of research activity in catalytic imine reduction, due to the ongoing motivation to find more efficient conversions of the rather unreactive C=N bonds to the desired C–N segments found in many pharmaceuticals. While several timely reviews have well documented various C=N reduction methodologies with respect to the type of catalyst (acid, base, or transition metal), a detailed discussion of the core role of thermodynamic driving forces in governing these catalyses is still lacking, however. Hence, this tutorial review describes some of the most practical considerations for adjusting reduction thermodynamics by choosing appropriate catalytic strategies, in order to make the target reduction energetically feasible. The combined use of relevant thermodynamic parameters of the substrate imines, hydrogen donors, and catalysts in realizing such a goal is demonstrated on the basis of the energetics of the possible elementary paths. Experimental observations from the literature that are in line with the present energetics-based analyses are exemplified. [ABSTRACT FROM AUTHOR]

The article presents a study which describes the mediation of a binary acid catalysis in the diastereoselectivity of cycloadditions with simple olefins. The study uses the model reaction of styrene for the analysis of the different counteranions, chiral phosphoric acids, and Lewis acids. Results show that the stereoselectivity in the utilization of a metal salt of phosphoric acid is improved by the presence of Lewis acid.

Ytterbium triflate was found to effectively catalyze the reaction of epoxides with nitrogen heterocycles. The reactions afforded hydroxyl alkylated products in high yields. [ABSTRACT FROM AUTHOR]

Anunprecedented intramolecular conjugate addition of simple alkenesto α,β-unsaturated carbonyl compounds has been developed.A simple Lewis acid such as Cu(OTf)2was found to effectivelycatalyze the reaction, and six- and five-membered cyclic productswere obtained in moderate to high yields. [ABSTRACT FROM AUTHOR]

Review: [71 refs. [ABSTRACT FROM AUTHOR]

Thefirst effective exampleof asymmetric conjugate addition–protonation reactions of thiolsto α-substituted vinyl ketones by chiral primary amine catalysisis reported. A simple chiral primary–tertiary diamine catalystderived from l-phenylalanine was found to promote the sulfa-Michaeladdition–protonation reactions with good to excellent enantioselectivity. [ABSTRACT FROM AUTHOR]

Abstract: Hydroxyl ionic liquid (HIL) has been explored as a novel support for Baylis–Hillman catalyst. The HIL-supported catalyst showed a better catalytic activity compared to other IL-immobilized catalyst that has no hydroxyl group attached to the IL scaffold. The hydroxyl group linked on IL played an important role in facilitating efficient catalysis under solvent-free conditions. The corresponding Baylis–Hillman and aza-Baylis–Hillman adducts were obtained in good to excellent yields in all cases examined. The HIL-supported quinuclidine can be readily recovered and reused for six times without significant loss of catalytic activity. [Copyright &y& Elsevier]

The azoles, which were inactive in neutral aqueous media, could be activated in alkaline solution and effectively catalyze the Baylis–Hillman reaction involving cyclic enones. [Copyright &y& Elsevier]

In aqueous media, imidazole was found to catalyse Baylis–Hillman reactions of cyclopent-2-enone with various aldehydes to afford the desired adducts with high yields. [Copyright &y& Elsevier]

This simple transfer diazenylation reaction exhibits good functional group compatibility, and provides a convenient approach for the synthesis of highly functionalized azo compounds. [ABSTRACT FROM AUTHOR]

The exchange of the metal ion from In(III) to Sc(III) in a binary acid catalyst leads to a switch in the diastereoselectivity of [4 + 2] cycloadditions. [ABSTRACT FROM AUTHOR]

The article presents chemical equations related to C-C coupling reaction, forming chemical bonds between carbon (C) atoms, between para-vinylanilines and aldehydes using primary-tertiary diamine and broensted acid as catalysts published in a 2013 issue of the "Chemistry: A European Journal."

Nazarov reaction of aryl vinyl β-ketoesters is optimally catalyzed by a binary acid catalyst consisting of In(OTf)3 and diphenyl phosphoric acid (DPP). [ABSTRACT FROM AUTHOR]

Review: 206 refs. [ABSTRACT FROM AUTHOR]