We report a palladium-catalyzed asymmetric [4+4] cycloaddition reaction between 2-alkylidenetrimethylene carbonate and electron-deficient indole-2,3-quinodimethanes (IQDMs). This reaction features exclusive regioselectivity, high yield (up to 98%), excellent enantioselectivity (up to 95% ee), and easy scale-up without any loss of efficiency, making it valuable for the synthesis of indole-fused eight-membered oxa-rings.
The picture in the background is the old chemistry building of Soochow University, the symbols of S are: 1. for the research field of Prof. Wang Shunyi's group at Soochow University: Organic Sulfur Chemistry; 2. for Soochow University; 3. for Suzhou; 4. for Singapore. We would like to take this opportunity to celebrate the 110th anniversary of the founding of Chemistry and Chemical Engineering in Soochow University, as well as the 30th anniversary of the Suzhou-Singapore Industrial Park. The cover image portrays the reductive coupling reaction of xanthate esters with sulfur-containing and selenium-containing compounds (thio(seleno)sulfonates and disulfides(selenides)) under the nickel-catalyzed condition. It provides a mild and effective method for the synthesis of unsymmetric sulfides and selenides. More details are discussed in the article by Wang et al. on pages 2453—2458.
The simultaneous construction of two vicinal C—C bonds in a molecule remains a significant challenge. In this work, we disclose an electroreductive carboarylation of activated alkenes under mild, transition metal-free conditions. Utilizing readily available starting materials (electron-deficient aryl bromides, activated alkenes, and CO2), this method demonstrates broad substrate scope and good functional group tolerance. Notably, this strategy enables the addition of two distinct electrophiles across an alkene in a highly chemo- and regioselective manner.
Electron transfer is an important way to activate persulfate. Currently, the electrons for persulfate activation mainly originate from organic contaminants or the catalyst itself, which can lead to selective activation of persulfate or oxidation of the catalyst, respectively, and thus become a bottleneck restricting its application. In this work, Cu−doped FeVO4 (Cu−FVO) was prepared, and the results showed that Cu doping can significantly improve the photocatalytic activity and stability of FVO for peroxymonosulfate (PMS) activation. The optimized Cu−FVO/PMS/light system exhibited a high BPA degradation rate that is 4.3 times higher than that of the FVO/PMS/light. This system manifested a broad applicability to various organic contaminants even with complex matrix. Photoelectrochemical analysis and DFT theoretical calculations revealed that Cu doping boosted the photogenerated charge separation and the adsorption of PMS on FVO. Furthermore, Cu doping led to the establishment of an electron transfer channel from Cu−FVO to PMS, through which photogenerated electrons achieved an efficient PMS activation. Meanwhile, holes were consumed by organic contaminants to avoid the oxidation of catalyst. These collectively enhanced the photocatalytic activity and stability of Cu−FVO, which also maintained high catalytic activity even after 20 cycling degradation reactions.
Five unreported and oxygenated ent-rosane diterpenoids (ent-RDs), Euphomillanols A—E (1—5), were isolated from Euphorbia milii. Among them, compounds 1 and 2 are unprecedented 7/7/6-fused tricyclic 5,10-seco-ent-RDs and possess a unique 11-oxabicyclo[4.4.1]undeca-1(10),5-diene moiety, while 3 is characterized by a 1-methyl-6-oxabicyclo[3.2.1]oct-2-ene motif of ring A. Their structures with absolute configurations were unambiguously determined by the extensive spectroscopic methods, X-ray crystallography, and ECD calculation. Putative biosynthetic pathways for compounds 1—3 are proposed. All compounds exhibited antiadipogenic effects in 3T3-L1 adipocytes, and the most potent compound 4 showed an EC50 value of 3.92 μmol/L with low cytotoxicity (IC50 > 89.54 μmol/L).
Two reaction modes for metal-free [3 + 2] cyclization of N-aminopyridinium derivatives with β-alkoxyvinyl trifluoromethylketones have been described through selective C—O or C—O/C—C bond cleavage. This strategy can also be extended to the [3 + 2] cyclization of N-aminopyridinium derivatives with enaminones and bromoalkynes. A broad range of N-aminopyridinium, N-aminoquinolinium, and N-aminoisoquinolinium salts are well tolerated, enabling the divergent synthesis of trifluoroacylated, non-substituted, acylated, and brominated pyrazolo[1,5-a]pyridine derivatives (62 examples).
With the continuous development of photovoltaic materials, organic solar cells (OSCs) have made remarkable advancements, surpassing a power conversion efficiency (PCE) of 20%. However, the PCEs of OSCs remain lower than that of inorganic solar cells due to significant energy losses, mainly stemming from the relatively large non-radiative recombination losses (usually be expressed as ∆E3), resulting in low open-circuit voltages. This can be achieved by reducing non-radiative recombination, and hereby increasing the electroluminescence quantum efficiency (EQEEL) of the photo-active layer. This review analyzes the significance of luminescence efficiency in achieving high-performance OSCs by examining the reciprocal relationship between ∆E3 and EQEEL. High-efficiency organic solar cells can also be used as effective organic light-emitting diodes (OLEDs). The discussion provides insights into the influencing factors of EQEEL and the mechanisms for adjusting various parameters, which include enhancements in photoluminescence quantum yield and the proportion of radiative excitons. The objective is to offer insights into the crucial role of luminescence performance in OSC development, guiding researchers toward developing novel photovoltaic materials or optimization strategies to enhance the luminescence performance of the active layer in OSCs, fostering the simultaneous advancement of OSCs and OLEDs.
An efficient asymmetric [4+2] cyclization of hydroxyphenyl indolinone with azlactone for the synthesis of spirooxindole δ-lactone has been developed, which realized the first asymmetric reaction of hydroxyphenyl indolinone. A series of intricate structures with congested vicinal quaternary chiral centers were provided in good yields with excellent enantioselectivities via the in situ generated o-QM from hydroxyphenyl indolinone.
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