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Nitrogen‐heterocycle‐based covalent organic frameworks (COFs) are considered promising candidates for the overall photosynthesis of hydrogen peroxide (H2O2). However, the effects of the relative nitrogen locations remain obscured and photocatalytic performances of COFs need to be further improved. Herein, a collection of COFs functionalized by various diazines including pyridazine, pyrimidine, and pyrazine have been judiciously designed and synthesized for photogeneration of H2O2 without sacrificial agents. Compared with pyrimidine and pyrazine, pyridazine embedded in TpDz tends to stabilize endoperoxide intermediate species, leading toward the more efficient direct 2e‐ oxygen reduction reaction (ORR) pathway. Benefiting from the effective electron‐hole separation, low charge transfer resistance, and high‐efficiency ORR pathway, an excellent production rate of 7327 μmol g−1 h−1 and a solar‐to‐chemical conversion (SCC) value of 0.62 % has been achieved by TpDz, which ranks one of the best COF‐based photocatalysts. This work might shed fresh light on the rational design of functional COFs targeting photocatalysts in H2O2 production. [ABSTRACT FROM AUTHOR]

Heterobiaryls are important pharmacophores that are challenging to prepare by traditional cross-coupling methods. An alternative approach is presented where pyridines and diazines are converted into heteroaryl phosphonium salts and coupled with aryl boronic acids. Nickel catalysts are unique for selective heteroaryl transfer, and the reaction has a broad substrate scope that includes complex pharmaceuticals. Phosphonium ions also display orthogonal reactivity in cross-couplings compared to halides, enabling chemoselective palladium- and nickel-catalyzed coupling sequences. [ABSTRACT FROM AUTHOR]

This study establishes a new trans-metal-trapping (TMT) procedure based on a mixture of LiTMP (the base) and tris(trimethylsilylmethyl)gallium [Ga(CH2SiMe3)3, GaR3] (the trap) that, operating in a tandem manner, is effective for the regioselective deprotonation of sensitive diazines in hydrocarbon solution, as illustrated through reactions of pyrazine, pyridazine, and pyrimidine, as well as through the N-S heterocycle benzothiazole. The metallo-activated complexes of all of these compounds were isolated and structurally defined. [ABSTRACT FROM AUTHOR]

Erlesene Sammlung: Die Titelreaktion liefert neuartige polycyclische Verbindungen mit hoher Ausbeute und exzellenter Diastereoselektivität unter milden Bedingungen. Eine Verbindungsbibliothek, die mithilfe dieser Reaktion aufgebaut wurde, führte zu einem neuen Chemotyp, der die glykolytische ATP ‐ Bildung durch Blockieren der Glukoseaufnahme in CHO ‐ K1 ‐ Zellen hemmte. DMF=N,N ‐ Dimethylformamid, Tf=Trifluormethansulfonyl, TIPS=Triisopropylsilyl. [ABSTRACT FROM AUTHOR]