Advanced Synthesis & Catalysis最新文献

Trifluoromethyl aryl diazirines are ubiquitous in chemical biology applications, and are increasingly used in materials science. While the electron-withdrawing α-CF₃ group is known to stabilize the carbene resulting from diazirine activation, no alternative electron-withdrawing groups have been systematically studied. Here, we describe the synthesis of the first α-ester aryl diazirines and show that they activate at lower temperatures than their trifluoromethyl-containing analogs, while still permitting tunable activation and good efficiency in CH insertion reactions. We anticipate the use of α-ester aryl diazirines in materials science applications (due to their high insertion yield with a nonfunctionalized aliphatic model substrate) and biological wound healing (due to their ability to be thermally activated at < 37°C).

Three-dimensional covalent organic frameworks (3D COFs) have emerged as promising materials for photocatalysis due to their interconnected pore channels, low density, high surface area, and robust chemical stability. However, the rational design and synthesis of 3D COFs with tailored photoresponsive properties remains a significant challenge. In this work, we incorporate two photoactive building blocks, spirobifluorene and N,N,N′,N′-tetra(p-aminophenyl)p-phenylenediamine (TPDA), and successfully fabricate a novel 3D COF, designated TPDA-COF, via solvothermal synthesis. Structural characterization unambiguously confirms its crb topology, whereas nitrogen adsorption measurements reveal a high BET surface area of 1747 m² g⁻¹. Importantly, spectroscopic and electrochemical studies demonstrate that TPDA-COF exhibits pronounced semiconductor behavior under visible-light irradiation. Electron paramagnetic resonance spectroscopy provides direct evidence for the generation of superoxide radical anions (O₂^•−) via photoinduced electron transfer from TPDA-COF to molecular oxygen (O₂). Leveraging this property, we employ TPDA-COF as a heterogeneous photocatalyst for the α-selective oxidation of N-substituted tetrahydroisoquinolines (THIQs) under mild conditions using O₂ as a green oxidant. The reaction proceeds with high efficiency and selectivity, demonstrating the capacity of the 3D framework to promote aerobic oxidative transformations. This study illustrates the structural benefits of 3D COFs and their potential as tunable sustainable photocatalysts for organic synthesis.

We present a method for the selective synthesis of thiochromanes and allyl sulfides that is both metal- and oxidant-free. This method uses 2-methylquinoline or acetophenone, paraformaldehyde, and thiols as substrates. Varying the thiol substrates allows for the controlled synthesis of either thiochromanes or allyl sulfides. This protocol uses HCl as a promoter, providing an easy, efficient way to produce these sulfur-containing compounds. Mechanistic studies suggest that the transformation proceeds via a Mannich-type reaction pathway.

We report the synthesis of 1,3-oxazole-substituted 2-naphthols and phenols from aryl heterobenzyl ethers via Claisen rearrangement by employing a Lewis acid-based ionic liquid as a promoter. Heterobenzyl-2-naphthyl ethers bearing electron-donating and -withdrawing groups produced exclusively [3,3]-sigmatropic Claisen rearranged products in excellent yields under the standard reaction conditions. Meanwhile, aryl heterobenzyl ethers bearing electron-donating and -withdrawing groups produced a mixture of rearranged products via [1,3] or [3,3]-Claisen or para-Claisen rearrangement. We also demonstrated a gram-scale reaction for this methodology. The reported ionic liquid can be reused for the subsequent cycles.

This review provides a comprehensive overview of asymmetric Negishi and Kumada crosscoupling reactions, covering key developments from the 1980s through 2025. It examines enantioselective and enantiospecific variants catalyzed by nickel, palladium, and cobalt complexes. The review discusses reaction scope, mechanistic ligand design and mechanistic understanding have enabled increasingly challenging transformations with high enantioselectivity Overall, this review demonstrates the power and versatility of asymmetric Negishi and Kumada couplings as valuable tools for constructing chiral molecules.

Organocatalyzed Chemoselective Oxidation

The cover uses the archery process as a metaphor, depicting the scene of the shooter selectively shooting arrows towards three different targets, symbolizing the selectivity of the chemical process. The bow is composed of the catalyst, providing the driving force; Arrows represent reaction materials, while different targets correspond to different products. Under the combined action of light and catalyst, by adjusting the reaction conditions (such as oxidant, reaction solvent), three different types of products can be generated respectively. More information can be found in the Research Article by Jichang Liu, Donghui Wei, Ning Liu, and co-workers (10.1002/adsc.70303).

In this study, we have synthesized a series of neutral and cationic silver complexes bearing two different redox-active N-heterocyclic carbene (NHC) ligands. Neutral complexes of the type Nq(IDipp)AgOCOR (R = CH₃ (2b), Ph (2c), CF₃ (2d)) were obtained via the reaction of imidazolium salts or the corresponding free carbenes with silver precursors. In contrast, cationic complexes of the general formula [Nq(NHC)₂Ag)]X (NHC = IDipp, X = BF₄ (3a), SbF₆ (3b); NHC = IMes, X = BF₄ (3c), SbF₆ (3d)) were prepared using AgX salts. The complex Nq(IDipp)AgOCOCH₃ (2b) was used as a catalyst for the carboxylative cyclization of substituted propargyl amines with CO₂ gas and outperforms the nonredox active NHC-silver complexes. This transformation enabled the development of a new and efficient catalytic protocol for the synthesis of a broad range of oxazolidine-2-ones in good to excellent yields. Notably, catalyst 2b exhibited excellent catalytic performance under mild conditions, operating effectively at low CO₂ gas concentrations and in the absence of bases or additives.

In this work, we describe how N-hydroxyphthalimide (NHPI), also under catalytic amounts, promotes hydrogen atom transfer (HAT) from alcohols under electrochemical conditions through the generation of phthalimide-N-oxyl (PINO). In contrast with the well-known electrochemical oxidation to their corresponding aldehydes or ketones, α-alkoxy radicals were successfully coupled with oximes promoting a carbon–carbon bond-forming event. This method allows the α-functionalization of primary and secondary alcohols under simple, straightforward, and mild electrochemical reaction conditions in a single operation even in the presence of catalytic amounts of the HAT catalyst.