Nickel Catalyzed Carbonylative Cross Coupling for Direct Access to Isotopically Labeled Alkyl Aryl KetonesMühlfenzl, Kim S.; Enemærke, Vitus J.; Gahlawat, Sahil; Golbækdal, Peter I.; Munksgaard‐Ottosen, Nikoline; Neumann, Karoline T.; Hopmann, Kathrin H.; Norrby, Per‐Ola; Elmore, Charles S.; Skrydstrup, Troels
doi: 10.1002/anie.202412247pmid: 39145496
Here we present an effective nickel‐catalyzed carbonylative cross‐coupling for direct access to alkyl aryl ketones from readily accessible redox‐activated tetrachlorophthalimide esters and aryl boronic acids. The methodology, which is run employing only 2.5 equivalents of CO and simple Ni(II) salts as the metal source, exhibits a broad substrate scope under mild conditions. Furthermore, this carbonylation chemistry provides an easy switch between isotopologues for stable (13CO) and radioactive (14CO) isotope labeling, allowing its adaptation to the late‐stage isotope labeling of pharmaceutically relevant compounds. Based on DFT calculations as well as experimental evidence, a catalytic cycle is proposed involving a carbon‐centered radical formed via nickel(I)‐induced outer‐sphere decarboxylative fragmentation of the redox‐active ester.
In Situ Generation of 1‐Acetylpyrene as a Visible‐Light Photocatalyst for the Thia‐Paternò‐Büchi ReactionCormier, Gabriel; Allain, Clémence; Boddaert, Thomas
doi: 10.1002/anie.202412602pmid: 39331387
The thia‐Paternò‐Büchi reaction represents a straightforward approach to build thietane cores. Unfortunately, the significant instability of thiocarbonyls, particularly thioketones and thioaldehydes, has hitherto rendered this photochemical [2+2]‐cycloaddition underexploited. To address this limitation, we report herein a visible‐light photochemical domino reaction including: the in situ generation of thiocarbonyls though a Norrish type II fragmentation of pyrenacyl sulfides, and the aforementioned thia‐Paternò‐Büchi reaction with various non‐volatile electron‐rich alkenes. The highly efficient synthesis of a wide range of unprecedented thietanes from intrinsically highly unstable thiocarbonyls, such as thioaldehydes and aliphatic thioketones, was made possible by the multitasking capability of pyrenacyl sulfides as a source of thiocarbonyl substrates and as precursors of 1‐acetylpyrene, which acts as the photocatalyst for the thia‐Paternò‐Büchi reaction. The photosensitizer properties of the latter have been experimentally established and a triplet‐triplet Dexter energy transfer based mechanism is proposed.
Eliminating Hydrogen Fluoride through Piperidine‐Doped Separators for Stable Li Metal Batteries with Nickel‐Rich CathodesDing, Luoyi; Chen, Yuanmao; Sheng, Yeliang; Yue, Xinyang; Liang, Zheng
doi: 10.1002/anie.202411933pmid: 39212463
Hydrofluoric acid (HF)‐induced electrode and interfacial structure degeneration poses a significant challenge for high‐voltage lithium metal batteries (LMBs). To address this issue, we propose a separator strategy that involves decorating a regular polyethylene (PE) separator with molecular sieves (TW) impregnated with piperidine (PI). The porous structure of the TW serves as a reaction chamber for PI and HF. As a result, the HF content in the controlled electrolyte with 500 ppm H2O (ELE‐500) is notably reduced when using TW@PI‐PE separators, thereby shielding nickel‐rich cathodes from HF etching. Simultaneously, due to the hydrolysis of Li salts, and the inertness of PI towards H2O, a uniform lithium fluoride (LiF)‐rich solid electrolyte interphase can form on the Li metal anode, further mitigating dendrite formation. The lifespan of the symmetric Li cell using the TW@PI‐PE separator is doubled in ELE‐500, exhibiting stable 500‐hour cycles at 3 mA cm−2 and 3 mAh cm−2. Additionally, with the effective limitation of transition metal (TM) dissolution, the 4.6‐V LMBs employing a LiNi0.8Co0.1Mn0.1O2 cathode maintain an 81 % capacity retention over 100 cycles, even in ELE‐1000. The innovative TW@PI system presented here offers a fresh perspective for future research aimed at eliminating HF in LMBs.
Pyrrolizwilline, a Unique Bacterial Alkaloid Assembled by a Nonribosomal Peptide Synthetase and non‐Enzymatic DimerizationEffert, Juliana; Westphalen, Margaretha; Calderari, Andrea; Shi, Yi‐Ming; Elamri, Isam; Najah, Soumaya; Grün, Peter; Li, Yanyan; Gruez, Arnaud; Weissman, Kira J.; Bode, Helge B.
doi: 10.1002/anie.202411258pmid: 39428351
Pyrrolizidine alkaloids (PAs) are a structurally diverse group of heterocyclic specialized metabolites characterized by a core structure comprising a hexahydro‐1H‐pyrrolizine. PAs are synthesized through two main pathways. In plants, assembly occurs via a homospermidine synthase, and in bacteria, through combined action of a nonribosomal peptide synthetase and a Baeyer–Villiger monooxygenase. While the toxic properties of plant‐derived PAs and their prevalence in animal and human foods have been extensively studied, the biological roles and biosynthesis of more complex bacterial PAs are not well understood. Here, we report the identification and characterization of a bacterial biosynthetic gene cluster from Xenorhabdus hominickii, xhpA‐G, which is responsible for producing the PA pseudo‐dimer pyrrolizwilline. Analysis of X. hominickii promoter exchange mutants together with heterologous expression of xhpA‐G in E. coli, revealed a set of pathway intermediates, two of which were chemically synthesized, as well as multiple derivatives. This information was leveraged to propose a detailed biosynthetic pathway to pyrrolizwilline. Furthermore, we have characterized the hydrolase XhpG, the key enzyme in the conversion of the pathway intermediate pyrrolizixenamide to pyrrolizwilline, using X‐ray crystallography and small‐angle X‐ray scattering (SAXS).
Asymmetric Synthesis of β‐Ketoamides by Sulfonium RearrangementPorte, Vincent; Nascimento, Vinicius R.; Sirvent, Ana; Tiefenbrunner, Irmgard; Feng, Minghao; Kaiser, Daniel; Maulide, Nuno
doi: 10.1002/anie.202418070pmid: 39440410
The synthesis of enantioenriched α‐substituted 1,3‐dicarbonyls remains a contemporary challenge in synthesis due to their tendency to undergo racemization via keto‐enol tautomerization. Herein, we report a method to access enantioenriched β‐ketoamides by a chiral sulfinimine‐mediated [3,3]‐sigmatropic sulfonium rearrangement. The transformation displays good chirality transfer, as well as excellent chemoselectivity and functional group tolerance. Diastereoselective reduction of the ketone moiety, also achievable in one‐pot fashion, affords enantioenriched β‐hydroxyamides.
Facile Synthesis of Potassium Decahydrido‐Monocarba‐closo‐Decaborate Imidazole Complex Electrolyte for All‐Solid‐State Potassium Metal BatteriesLu, Zhiwei; Qiu, Pengtao; Zhai, Hanyu; Zhang, Guo‐Guo; Chen, Xin‐Wei; Lu, Zhansheng; Wu, Yiying; Chen, Xuenian
doi: 10.1002/anie.202412401pmid: 39243107
All‐solid‐state potassium metal batteries have caught increasing interest owing to their abundance, cost‐effectiveness, and high energy/power density. However, their development is generally constrained by the lack of suitable solid‐state electrolytes. Herein, we report a new complex KCB9H10 ⋅ 2C3H4N2, synthesized by grinding and heating the mixture of potassium decahydrido‐monocarba‐closo‐decaborate (KCB9H10) and imidazole (C3H4N2) under mild conditions, to achieve the K‐ion superionic solid‐state electrolyte. The crystal structure was revealed as an orthorhombic lattice with the space group of Pna21 by FOX software. The diffusion properties for K+ in the crystal structure were calculated using the climbing image nudged elastic band (CI‐NEB) method. KCB9H10 ⋅ 2C3H4N2 exhibited a high ionic conductivity of 1.3×10−4 S cm−1 at 30 °C, four orders of magnitude higher than that of KCB9H10. This ionic conductivity is also the highest value of hydridoborate‐based K+ conductors reported. Moreover, KCB9H10 ⋅ 2C3H4N2 demonstrated a K+ transference number of 0.96, an electrochemical stability window of 1.2 to 3.2 V vs. K/K+, and good stability against the K metal coated by a layer of potassium imidazolate (KIm). These great performances make KCB9H10 ⋅ 2C3H4N2 a promising K‐ion solid‐state electrolyte.