Beilstein Journal of Organic Chemistry最新文献

We present a mechanochemical synthesis of difluoromethyl enol ethers. Utilizing an in situ generation of difluorocarbenes, ketones are efficiently converted to the target products under solvent-free conditions. The reactions proceed at room temperature and are complete within 90 minutes, demonstrating both efficiency and experimental simplicity.

Unlike their planar counterparts, classic synthetic protocols for C-C bond forming reactions on nonplanar porphyrins are underdeveloped. The development of C-C bond forming reactions on nonplanar porphyrins is critical in advancing this field of study for more complex porphyrin architectures, which could be used in supramolecular assemblies, catalysis, or sensing. In this work a library of arm-extended dodecasubstituted porphyrins was synthesized through the optimization of the classic Suzuki-Miyaura coupling of peripheral haloaryl substituents with a range of boronic acids. We report on palladium-catalyzed coupling attempts on the ortho-, meta-, and para-meso-phenyl position of sterically demanding dodecasubstituted saddle-shaped porphyrins. While para- and meta-substitutions could be achieved, ortho-functionalization in these systems remains elusive. Furthermore, borylation of a dodecasubstituted porphyrin's meso-phenyl position was explored and a subsequent C-C coupling showed the polarity of the reaction can be reversed resulting in higher yields. X-ray analysis of the target compounds revealed the formation of supramolecular assemblies, capable of accommodating substrates in their void.

Treatment of various (R)-N-(2,2,3,3-tetrafluoropent-4-en-1-ylidene)-1-phenylethylamine derivatives with 2.4 equiv of DBU in toluene at room temperature to 50 °C for 24 h led to a smooth [1,3]-proton shift reaction with a high chirality transfer, affording the corresponding rearranged products in acceptable yields. Without purification, these products were subjected to acid hydrolysis and the subsequent N-Cbz protection, providing the optically active tetrafluoroethylenated amides in moderate three-step yields.

The catalytic (asymmetric) allylation and propargylation have been established as powerful strategies allowing access to enantioenriched α-chiral alkenes and alkynes. In this context, combining allylic and propargylic substitutions offers new opportunities to expand the scope of transition metal-catalyzed substitution reactions. Since its discovery in 2022, copper-catalyzed yne-allylic substitution has undergone rapid development and significant progress has been made using the key copper vinyl allenylidene intermediates. This review summarizes the developments and illustrates the influences of copper salt, ligand, and substitution pattern of the substrate on the regioselectivity and stereoselectivity.

We have reported that upon visible light irradiation, ferrocene-porphyrin-[60]fullerene triad molecules yield long-lived charge-separated states, enabling the control of the plasma membrane potential (V _m) in living cells. These previous studies indicated that the localization of the triad molecules in a specific intra-membrane orientation and the suppression of the photodynamic actions of the [60]fullerene (C₆₀) moiety are likely important to achieve fast and safe control of V _m, respectively. In this study, by mimicking our previous system of triad molecules and living cells, we report a simplified model system with a cationic C₆₀ derivative (catC₆₀) and a liposome with embedded 1-pyrenebutyric acid (PyBA) to demonstrate that the addition of PyBA was important to achieve fast and safer control of V _m.

Spiro-heterocyclic indolenines are privileged scaffolds widely present in numerous indole alkaloids. Here, we develop a novel approach for the one-pot multistep synthesis of different spiro[indole-isoquinolines]. The protocol proposed involves the visible light mediated oxidation of N-aryl tertiary amines using bromochloroform with the generation of a reactive iminium species, which reacts with an isocyanide and an electron-rich aniline in a three-component Ugi-type reaction to give an α-aminoamidine. This compound might undergo an additional visible light-mediated oxidation to furnish a second iminium intermediate, which acts as electrophile in an intramolecular electrophilic aromatic substitution giving the final spiro-indolenine. The scope of the process has been investigated with respect to all three components. Simple operations, mild conditions, and good yields make this strategy a convenient and sustainable way to obtain novel spiro-indolenine derivatives.

We report the synthesis of polycyclic uracil derivatives. The method is based on palladium-catalysed Sonogashira-Hagihara and Suzuki-Miyaura cross-coupling reactions followed by Brønsted acid-mediated cycloisomerisation. The developed methodology tolerates various functional groups and leads to moderate up to quantitative yields of the final products. The impact of different functional groups on the optical properties was studied by UV-vis and fluorescence spectroscopy.

In this study, we develop the synthesis methods of fluoroalkenes and fluoroenynes via Suzuki-Miyaura and Sonogashira cross-coupling reactions using novel multihalogenated fluorovinyl ethers, which are easily prepared from the reaction between phenols and 2-bromo-2-chloro-1,1,1-trifluoroethane (halothane). These reactions make use of the unique structure of multihalogenated fluorovinyl ethers, which contains a reactive bromine atom, to afford a series of fluoroalkenes and fluoroenynes in moderate to high yields.