A Highly Efficient and Selective Aerobic Cross‐Dehydrogenative‐Coupling Reaction Photocatalyzed by a Platinum(II) Terpyridyl Complex

Thanks to the superior redox potential of platinum(II) complex compared with that of Ru(bpy)₃²⁺ in the excited state, an efficient and selective visible‐light‐induced CDC reaction has been developed by using a catalytic amount (0.25 %) of 1 . With the aid of FeSO₄ (2 equiv), the corresponding amide could not be detected under visible‐light irradiation (λ=450 nm), but the desired cross‐coupling product was exclusively obtained under ambient air conditions. A spectroscopic study and product analysis revealed that the CDC reaction is initiated by photoinduced electron‐transfer from N‐phenyltetrahydroisoquinoline to the complex. An EPR (electron paramagnetic resonance) experiment provides direct evidence on the generation of superoxide radical anion (O₂^{? .} ) rather than singlet oxygen (¹O₂) under irradiation of the reaction system, in contrast to that reported in the literature. Combined, the photoinduced electron‐transfer and subsequent formation of superoxide radical anion (O₂^{? .} ) results in a clean and facile transformation.     

A Porous and Stable Porphyrin Metal‐Organic Framework as an Efficient Catalyst towards Visible‐Light‐Mediated Aerobic Cross‐Dehydrogenative‐Coupling Reactions

Porphyrin metal‐organic frameworks (PMOFs) are emerging as heterogeneous photocatalysts owing to the well‐designed frameworks incorporated with powerful light‐harvesting porphyrin chromophores. The porous and stable framework Ir?PCN‐224 (which is also denoted as Ir?PMOF‐1), which has been prepared by the self‐assembly of Ir(TCPP)Cl (TCPP=tetrakis(4‐carboxyphenyl)porphyrin) and ZrCl₄, is reported herein to be efficient for the aerobic cross‐dehydrogenative carbon?phosphorus coupling reaction, giving rise to a high turn‐over number (TON) of up to 17200 under visible light irradiation (λ≥420 nm). Electron paramagnetic resonance (EPR) experiments disclose that the active species might be the superoxide radical anion (O₂^.?). Additionally, the intermediate imine cation has been detected by high‐resolution mass spectrometry (HRMS).     

Iron(II)‐Catalyzed Biomimetic Aerobic Oxidation of Alcohols

We report the first Fe^II‐catalyzed biomimetic aerobic oxidation of alcohols. The principle of this oxidation, which involves several electron‐transfer steps, is reminiscent of biological oxidation in the respiratory chain. The electron transfer from the alcohol to molecular oxygen occurs with the aid of three coupled catalytic redox systems, leading to a low‐energy pathway. An iron transfer‐hydrogenation complex was utilized as a substrate‐selective dehydrogenation catalyst, along with an electron‐rich quinone and an oxygen‐activating Co(salen)‐type complex as electron‐transfer mediators. Various primary and secondary alcohols were oxidized in air to the corresponding aldehydes or ketones with this method in good to excellent yields.     

通过调控肿瘤代谢增强T细胞抗肿瘤活性

肿瘤免疫治疗是一种新型的癌症治疗方法。 然而,现阶段肿瘤免疫疗法的临床响应率低等问题严重制约了其进一步应用。 其根本原因在于肿瘤组织免疫抑制微环境限制了T细胞的抗肿瘤活性,而肿瘤组织代谢改变在肿瘤免疫抑制微环境形成过程中起关键作用。 本文重点总结了通过调控肿瘤的有氧糖酵解、氨基酸代谢和脂肪酸代谢增强T细胞的抗肿瘤活性。 最后,提出当前肿瘤代谢调控研究方面仍然存在的问题,并对纳米载体在肿瘤代谢领域的发展前景进行了展望。     

Visible-Light-Driven C−H Oxidation of Cyclic Tertiary Amines: Access to Synthetic Strychnos Alkaloids with Antiviral Activity

Air and visible light have been used in facile direct C−H oxidation of cyclic tertiary amines at ambient conditions, employing organic dyes as photocatalysts and LED. Tolerance of this new environmentally compatible protocol to various side-chain derivatizations of tryptoline and tetrahydroisoquinoline substrates was demonstrated. The developed method provides a straightforward and sustainable route towards δ-lactams, which feature strong antiviral properties (EC₅₀ down to 4.6±1.8 μm ) against human cytomegalovirus (HCMV). The clear advantages, which are easily available and inexpensive reagents, organic dyes, visible light, air/O₂ and atom efficiency, make this system highly appealing for synthesis of versatile Strychnocarpine alkaloid derivatives with antiviral activity.