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Continuous-flow rhodium-catalysed hydroformylation of long chain alkenes has been achieved with selectivities to the desired linear aldehyde of 92% and minimum rhodium loss, using a xantphos-derived ligand attached to an imidazolium salt in a supercritical fluid–ionic liquid system. The effect of oxygen in the system can be ameliorated to some extent by adding a simple sulfonated triphenylphosphine to the catalytic solution. [ABSTRACT FROM AUTHOR]

Direct cleavage of the C–C bond in lignin linkages is a promising route to afford value-added aromatics, which, however, usually involves metal-based catalysts and harsh conditions. Here, a photo-thermal strategy is reported to deconstruct the Cα–Cβ bond in lignin β-O-4 and β-1 interlinkages in the ionic liquid [BMim][NTf2]. It was found that the synergism of UV light and heating could trigger the Norrish type I reaction by inducing the cleavage of the Cα–Cβ bond and afford aromatic aldehydes through a free radical route in modest yields. Meanwhile, [BMim][NTf2] could interact with lignin moieties and stabilize the intermediates, which significantly contribute to the Cα–OH protonation and accelerate lignin interunit linkage breakage. In this unique route, the Cα–Cβ bond could be cleaved at 50 °C under UV light irradiation without the presence of a metal. Further comparison with photochemical or thermochemical alone strategies demonstrates that the photo-thermal route offers a significant improvement in the Cα–Cβ bond cleavage reactivity. Alkali lignin could also be degraded into aromatic monomers in [BMim][NTf2] using the protocol. Given the necessity of biomass upgradation, this work may provide a green and unique technology to boost the inert C–C bond cleavage upon photo-thermal synergism under metal-free and mild conditions that may underpin future advances in photo-thermal transformation and renewable energy production. [ABSTRACT FROM AUTHOR]

An efficient protocol has been developed for the synthesis of 2,3-dihydroquinazolinone compounds from anthranilamide and aldehydes or ketones via ionic liquid catalyzed cyclization reaction. The reaction features high efficiency, shorter reaction duration, mild reaction conditions and inexpensive reagents. The catalyst was recovered and reused. The recyclability of ionic liquid resulted in excellent yields of products without loss of any catalytic activity. [ABSTRACT FROM AUTHOR]

2-Methylenecyclobutanones (2-MCBones), used to be difficult to access, but can now be easily achieved by a green and stereospecific Ca(OH) 2-catalyzed direct and simple aldol condensation of cyclobutanone and aldehydes under mild conditions. The obtained (E)-2-MCBones should be a class of potentially useful building blocks in synthesis as they could readily undergo an interesting (PhSe) 2-catalyzed Baeyer-Villiger (BV) oxidation with H2O2 at room temperature to give the versatile 4-methylenebutanolides. Mechanistic studies revealed that the BV reaction most possibly proceeded via the initial formation of benzeneseleninoperoxoic anhydride [PhSe(O)O]2O, which then converted to benzeneseleninoperoxoic acid PhSe(O)OOH as the active oxidant, followed by its selective addition to the C=O bond of 2-MCBones and then a selective C-C bond cleavage and rearrangement to give 4-methylenebutanolides. [ABSTRACT FROM AUTHOR]

A supported dual acidic ionic liquid catalyst was prepared viaanchoring 3-sulfobutyl-1-(3-propyltriethoxysilane) imidazolium hydrogen sulfate onto silica gel by covalent bonds. The novel immobilized acidic ionic liquid effectively catalyzed the one-pot synthesis of amidoalkyl naphthols by the multicomponent condensation of aldehydes with 2-naphthol and amides under solvent-free conditions. Moreover, the catalyst could be recycled six-times without a significant loss of catalytic activity. [ABSTRACT FROM AUTHOR]

The catalyst system that comprises an air-stable bifunctional Lewis acidic/basic organobismuth complex and [Bmim]BF4is highly efficient in the cross-condensation of aldehydes with ketones. Through switching the reaction from homogeneous to heterogeneous, the system shows facile separation ability and facile reusability. [ABSTRACT FROM AUTHOR]

The photo-Friedel–Crafts acylation of 1,4-naphthoquinone with various aldehydes was investigated in a series of room temperature ionic liquids. High conversions and selectivities were achieved in [C2mim]+-based ionic liquids with the highest isolated yields found in [C2mim][NTf2]. The developed procedure allowed for a replacement of hazardous solvents such as benzene and acetonitrile which are commonly used for this transformation. [ABSTRACT FROM AUTHOR]

A simple and efficient procedure for the synthesis of 2-substituted benzimidazoles has been developed by a one-pot reaction of o-phenylenediamine with aromatic aldehydes in the presence of an ionic liquid, 1-methyl-3-pentylimidazolium tetrafluoroborate, [pmim]BF4at room temperature in open air without any organic solvent. The ionic liquid is recycled. A remarkable influence of the substituent on the imidazolium unit of the ionic liquid on the outcome of the reaction is observed. [ABSTRACT FROM AUTHOR]