Visible-light photoredox catalysis has been esteemed as one sustainable and attractive synthetic tool. In the past four years, a new yet challenging trend, visible-light-driven redox-neutral radical ...C-C cross-coupling involving putative radical intermediates, has been booming rapidly. Its advent brings a powerful platform to achieve non-classical C-C connections, and should lead to fundamental changes in retrosynthetic analysis. In this tutorial review, we highlight the recent achievements of visible-light-mediated redox-neutral radical C(sp
3
)-C(sp
2
), C(sp
3
)-C(sp), and C(sp
3
)-C(sp
3
) bond formation, opening a new window for C-C cross-coupling through the photoredox electron shuttling cycle between two coupling partners. While radical-radical coupling steered by the persistent radical effect was proposed as a rational explanation for the redox-neutral photoredox events, alternative kinetically driven chain propagation and radical addition pathways cannot be ruled out. This tutorial review aims to highlight the recent achievements of photoredox-neutral radical C-C coupling in synthetic chemistry.
Visible-light-driven redox-neutral radical C-C coupling brings a powerful platform to achieve non-classical C-C connection in the absence of external reductants or oxidants through a photoredox electron shuttling cycle.
In recent years, visible-light-mediated C–H bond functionalization has become an emerging field at the forefront of organic synthesis. It is of considerable interest to academic and industrial ...chemists owing to the atom/step economical features as well as the overall sustainability. In this Letter, we mainly discussed the recent typical examples in sp2 and sp3 C–H bond functionalization by means of visible-light photoredox catalysis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
An elegant approach to quaternary oxindole formation has been developed through a room temperature decarboxylation/radical C-H functionalization by visible-light photoredox catalysis.
A facile, site‐selective, and divergent approach to construct 2‐aminopyrroles and quinoline‐fused polyazaheterocycles enabled by a simple gold(III) catalyst from ynamides and anthranils under mild ...reaction conditions is described. This one‐pot strategy uses readily available starting materials, proceeds in a highly step‐ and atom‐economical manner, with broad substrate scope and scale‐up potential. The key element for success in this tandem reaction is a catalyst‐directed preferred quenching of the in situ generated gold carbene intermediates by a nucleophilic benzyl/2‐furylmethyl moiety on the ynamides as an alternative to the known C−H annulation leading to indoles.
One‐pot strategy: A simple gold(III) catalyst enables the construction of 2‐aminopyrroles and quinoline‐fused polyazaheterocycles from ynamides and anthranils under mild reaction conditions. This strategy uses readily available starting materials, proceeds in a highly step‐ and atom‐economical manner, with broad substrate scope and scale‐up potential.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Pt(II) and Au(III)-mediated intermolecular divergent annulations of benzofurazans and ynamides highlighted the N- to O-selectivity of tunable metal carbene intermediates. PtCl
with a bulky phosphite ...ligand resulted in the specific synthesis of six-membered quinoxaline N-oxides and successfully suppressed the in-situ deoxygenation of N-oxides. On the other hand, an unique gold(III) catalyst (2,6-di-MeO-PyrAuCl
) led to the five-membered ring products, benzimidazoles. A broad scope of functional groups was well compatible, delivering better yields and selectivities in contrast to conventional gold(I) catalysts. The different behavior of presumed platinum(II) and gold(III) carbenes with respect to chemoselectivity was intensively examined by experiments and DFT calculations. A detailed mechanistic study, based on DFT calculations, revealed that the highly electrophilic carbocation-like gold(III) carbene triggers an oxophilic cyclization, followed by a cascade ring contraction and acyl migration. On the contrary, the Pt carbene species is less cationic, favoring the formation of the six-membered ring via N-attack.
A novel and highly efficient gold(III)-complex catalyzed aerobic oxidative α-C-H functionalization of amines has been developed. The tertiary amines can be directly coupled with various nucleophiles ...using air as a sustainable oxidant.
A copper-mediated C2-cyanation of indoles using cheap and commercially available acetonitrile as the “nonmetallic” cyanide source was achieved through sequential C–C and C–H bond cleavages. The ...installation of a removable pyrimidyl group on the indole nitrogen atom is the key for this C2 selectivity. This approach provides a novel and alternative route leading to indole-2-carbonitrile.
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IJS, KILJ, NUK, PNG, UL, UM
The bicyclic isoxazolidine scaffolds are the ubiquitously recurring motifs in alkaloids. Despite of their facile biosynthesises in nature, the laboratory synthesis of these derivatives is still ...complicated. In this paper, the isoxazolidine derivatives are concisely constructed in one process with excellent stereoselectivity from simple tertiary amines through a C-H activation-retro-aza-Michael-oxidation-cyclization tandem sequence by means of visible-light. This protocol provides a concise approach to dactylicapnosinine derivatives.
A C-H activation-retro-aza-Michael-oxidation-cyclization tandem sequence has been developed for concise construction of bicyclic isoxazolidines from tertiary amines by means of visible-light photoredox catalysis.
Early‐stage lung cancer is now more commonly identified in the form of ground‐glass nodules (GGNs). Presently, the treatment of lung cancer with GGNs mainly depends on surgery; however, issues still ...exist such as overtreatment and delayed treatment due to the nonuniform standard of follow‐up. Therefore, the discovery of a noninvasive treatment could expand the treatment repertoire of ground‐glass nodular lung cancer and benefit the prognosis of patients. Immunotherapy has recently emerged as a new promising approach in the field of lung cancer treatment. Thus, this study presents a comprehensive review of the immune microenvironment of lung cancer with GGNs and describes the functions and characteristics of various immune cells involved, aiming to provide guidance for the clinical identification of novel immunotherapeutic targets.
Immunotherapy is occupying an increasingly crucial position in the treatment of lung cancer. However, the immunotherapeutic approaches for ground‐glass nodules are still not fully developed, which implies that conducting research on the immune microenvironment is definitely a way to seek effective immunotherapy. In this study, we reviewed the differences in the abundance and functionality of various immune cells among normal lung tissue, ground‐glass nodule lung adenocarcinoma and solid nodule lung adenocarcinoma, and further discussed the complex tumor immune microenvironment formed by various immune cells through intercellular contact or cytokine secretion, with the aim of uncovering potential immunotherapeutic targets for ground‐glass nodule lung adenocarcinoma.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The poor performance of LiNi
0.5
Co
0.2
Mn
0.3
O
2
cathode materials in lithium-ion batteries under high cut-off voltage, such as fast capacity fading and poor cycle capability, hinders the ...development of high energy density lithium-ion batteries. Surface modification is generally conducted on the electrode to improve high cut-off voltage performance. In this study, Al
2
O
3
and graphene are co-coated on the surface of LiNi
0.5
Co
0.2
Mn
0.3
O
2
. The Al
2
O
3
/graphene co-coating layer effectively reduces side reactions and HF erosion and facilitates lithium-ion diffusion/electronic conduction. The degree of cation mixing and electrode polarization is also decreased by the co-coating from the XRD and cyclic voltammetry results. The modified sample exhibits improved electrochemical properties under high cut-off voltage (3–4.5 V): The initial discharge capacity and coulombic efficiency of the modified sample reaches 187.2 mAh g
−1
and 87.0%, which is higher than the pristine NCM (161.0 mAh g
−1
, 82.9%). The co-coating electrode possesses a high cycling retention of 88.2% with 10% improvement at a current density of 180 mA·g
−1
(1 C) after 200 cycles, and the rate capability reaches 119.6 mAh·g
−1
at 1800 mA·g
−1
(10 C), compared to 78.6 mAh·g
−1
of the pristine sample. The modification effect in different voltage ranges (3–4.5 V and 3–4.3 V) was compared, which shows a more significant improved effect under high voltage than low voltage: The cycle retention after 200 cycles is increased by 10% at 3–4.5 V, higher than 7.7% (3–4.3 V), which is due to the intensified side reactions under high voltage being suppressed by co-coating.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
