Latest ArticlesSulfoxonium ylides as carbene precursors couple smoothly with thioureas in the presence of 5 mol% of rhodium(Ⅱ) acetate dimmer via carbenoid insertion to afford the corresponding 2-aminothiazoles with high chemoselectivity, providing a facile and efficient approach to access a variety of 2-aminothiazole derivatives with good functional groups tolerance.
An efficient and facile method for C–H amination of quinoxalinones with heteroaromatic amines under metal-free conditions has been described. In the presence of hypervalent PIDA reagent, the desired products with various groups were obtained with moderate to high yields.
A series of multi-(phenylthio)porphyrinato Ni(ò) compounds were synthesized without the participation of transition metal catalysts. All of these products were well characterized by 1H NMR, 13C NMR and HRMS. Structures of three typical compounds were further confirmed by X-ray single crystal diffraction. Remarkable red shifts were observed in UVɃvis absorption spectra of multi-(phenylthio)porphyrinato Ni(ò) compounds which meet well with the electrochemical data. DFT calculation indicates that the phenylthio groups have strong effects on the frontier orbitals of these molecules. The order of a1u-like and a2u-like orbitals mainly distributed in porphyrin moiety is often inversed in energy when multi-phenylthio groups are attached.
An N-heterocyclic carbene (NHC)-catalysed retro-aldol/aldol cascade reaction of spirooxindole-based β-hydroxyaldehyde has been developed. The ring opening-closure process enables the diastereodivergent synthesis of spirocyclopentaneoxindole products with four consecutive stereocenters by simply changing the reaction solvents (THF or DCE). The Michael/aldol/retro-aldol/aldol sequential protocol allows the diastereodivergent synthesis of spirocyclopentaneoxindoles from 3-substituted oxindole and α, β-unsaturated aldehyde under the relay catalysis of a chiral secondary amine and an NHC catalyst. Moreover, four stereoisomers of the product can be selectively provided by using different combinations of a chiral secondary amine and a solvent.
In this paper, the host-guest interaction of cucurbit[7]uril (Q[7]) and chromone (CMO) has been developed as a fluorescent probe for the highly selective detection of Zn2+ and Cd2+ in water based on a chelation-enhanced fluorescence (CHEF) mechanism. There was a good linear relationship between the fluorescence intensity of the CMO@Q[7] probe and the concentration of Zn2+ or Cd2+ in the range of 0–3.0 × 10–5 mol/L and the detection limit for Zn2+ and Cd2+ was found to be 2.03 × 10–6 mol/L and 1.89 × 10–6 mol/L, respectively. The X-ray crystal structure indicated that different coordination fashions were triggered by Zn2+ and Cd2+ in the CMO@Q[7] complexes, respectively. However, both metal ions coordinated with the carbonyl oxygen of CMO, which was encapsulated in the cavity of Q[7], thus leading to the enhancement of recognition fluorescence emission of CMO.
A visible light and base promoted O-H insertion/cyclization of para-quinone methides with aryl diazoacetates is developed. This one-pot two step reaction offers a mild and efficient approach for the synthesis of biologically important 2, 3-dihydrobenzofuran derivatives in good yields and moderate diastereoselectivities.
Visible-light-driven photochemical Cadogan-type cyclization has been discovered. The organic D-A type photosensitizer 4CzIPN found to be an efficient mediator to transfer energy from photons to the transient intermediate that breaks the barriers of deoxygenation in Cadogan reaction and enables a mild metal-free access to carbazoles and related heterocycles. DFT calculation results indicate mildly endergonic formation of the intermediate complex of nitrobiarenes and PPh3, which corresponds with experimental findings regarding reaction temperature. The robust synthetic capacity of the photoredox Cadogan reaction systems has been demonstrated by the viable productivity of a broad range of carbazoles and related N-heterocycles with good tolerance of various functionalities.
An intramolecular selenocyclizations of olefins mediated by a commercially available hypervalent iodine(III) reagent, PhIO, was developed. This method provided access to a wide range of selenenylated heterocycles under ambient conditions. The striking advantages of this protocol over all previous methods include mild reaction conditions, easy operation, good yields, high levels of functional group compatibility, large–scale application and suitability for the late-stage functionalization of complex molecules of biological importance.
A novel approach for the synthesis of 4-aminoquinazolines has been developed via rhodium(III)-catalyzed [4 + 2] annulation of N-arylbenzamidines with 1, 4, 2-dioxazol-5-ones. This reaction features excellent regioselectivity, broad substrate scope and high step economy, which would provide the reference for the construction of the fused 4-aminoquinazolines with biologically and pharmacologically active compounds.
As a close relative of ferroelectricity, antiferroelectricity has received a recent resurgence of interest driven by technological aspirations in energy-efficient applications, such as energy storage capacitors, solid-state cooling devices, explosive energy conversion, and displacement transducers. Though prolonged efforts in this area have led to certain progress and the discovery of more than 100 antiferroelectric materials over the last 70 years, some scientific and technological issues remain unresolved. Herein, we provide perspectives on the development of antiferroelectrics for energy storage and conversion applications, as well as a comprehensive understanding of the structural origin of antiferroelectricity and field-induced phase transitions, followed by design strategies for new lead-free antiferroelectrics. We also envision unprecedented challenges in the development of promising antiferroelectric materials that bridge materials design and real applications. Future research in these directions will open up new possibilities in resolving the mystery of antiferroelectricity, provide opportunities for comprehending structure-property correlation and developing antiferroelectric/ferroelectric theories, and suggest an approach to the manipulation of phase transitions for real-world applications.