Construction of Axially Chiral Arylpyrroles via Atroposelective Diyne CyclizationChen, Yang‐Bo; Liu, Li‐Gao; Chen, Can‐Ming; Liu, Yi‐Xi; Zhou, Bo; Lu, Xin; Xu, Zhou; Ye, Long‐Wu
doi: 10.1002/anie.202303670pmid: 36996038
Axially chiral biaryls widely exist in natural products and pharmaceuticals and are used as chiral ligands and catalysts in asymmetric synthesis. Compared to the well‐established axially chiral 6‐membered biaryl skeletons, examples of 5‐membered biaryls have been quite scarce, and mono‐substituted 3‐arylpyrrole atropisomers have not been reported. Here, we disclose a copper‐catalyzed atroposelective diyne cyclization for the construction of a range of axially chiral arylpyrrole biaryls in good to excellent yields with generally excellent enantioselectivities via oxidation and X−H insertion of vinyl cations. Importantly, this protocol not only represents the first synthesis of mono‐substituted 3‐arylpyrrole atropisomers, but also constitutes the first example of atroposelective diyne cyclization and the first atropisomer construction via vinyl cations. Theoretical calculations further support the mechanism of vinyl cation‐involved cyclization and elucidate the origin of enantioselectivity.
Ultra‐Permeable Dual‐Mechanism‐Driven Graphene Oxide Framework Membranes for Precision Ion SeparationsGuo, Jing; Zhang, Yanqiu; Yang, Fan; Mamba, Bhekie B.; Ma, Jun; Shao, Lu; Liu, Shaomin
doi: 10.1002/anie.202302931pmid: 37015013
Two‐dimensional graphene oxide (GO) membranes are gaining popularity as a promising means to address global water scarcity. However, current GO membranes fail to sufficiently exclude angstrom‐sized ions from solution. Herein, a de novo “posterior” interfacial polymerization (p‐IP) strategy is reported to construct a tailor‐made polyamide (PA) network in situ in an ultrathin GO membrane to strengthen size exclusion while imparting a positively charged membrane surface to repel metal ions. The electrostatic repulsion toward metal ions, coupled with the reinforced size exclusion, synergistically drives the high‐efficiency metal ion separation through the synthesized positively charged GO framework (PC‐GOF) membrane. This dual‐mechanism‐driven PC‐GOF membrane exhibits superior metal ion rejection, anti‐fouling ability, good operational stability, and ultra‐high permeance (five times that of pristine GO membranes), enabling a sound step towards a sustainable water‐energy‐food nexus.
Boosting the Efficiency of Dye‐Sensitized Solar Cells by a Multifunctional Composite Photoanode to 14.13 %Zhang, Siqi; Huang, Fuhua; Guo, Xugeng; Xiong, Ye; Huang, Yafei; Ågren, Hans; Wang, Li; Zhang, Jinglai
doi: 10.1002/anie.202302753pmid: 37026187
We report a new strategy to fabricate a multifunctional composite photoanode containing TiO2 hollow spheres (TiO2‐HSs), Au nanoparticles (AuNPs) and novel NaYF4 : Yb,Er@NaLuF4 : Eu@SiO2 upconversion nanoparticles (UCNPs). The AuNPs are grown on the photoanode film including TiO2‐HSs and UCNPs by a simple in situ plasmonic treatment. As a result, an impressive power conversion efficiency of 14.13 % is obtained, which is a record for N719 dye‐based dye‐sensitized solar cells, demonstrating great potential for the solar cells toward commercialization. This obvious enhancement is ascribed to a collaborative mechanism of the TiO2‐HSs exhibiting excellent light‐scattering ability, of the UCNPs converting near‐infrared photons into visible photons and of the AuNPs presenting outstanding surface plasmon resonance effect. Notably, a steady‐state experiment further reveals that the champion cell exhibits 95.33 % retainment in efficiency even after 180 h of measurements, showing good device stability.
Palladium‐Catalyzed Benzylic C(sp3)−H Carbonylative Arylation with Aryl BromidesHu, Bowen; Zhao, Haoqiang; Wu, Yu; Walsh, Patrick J.
doi: 10.1002/anie.202300073pmid: 37005225
A novel, selective and high‐yielding palladium‐catalyzed carbonylative arylation of a variety of weakly acidic (pKa 25–35 in DMSO) benzylic and heterobenzylic C(sp3)−H bonds with aryl bromides has been achieved. This system is applicable to a range of pro‐nucleophiles for access to sterically and electronically diverse α‐aryl or α,α‐diaryl ketones, which are ubiquitous substructures in biologically active compounds. The Josiphos SL‐J001‐1‐based palladium catalyst was identified as the most efficient and selective, enabling carbonylative arylation with aryl bromides under 1 atm CO to provide the ketone products without the formation of direct coupling byproducts. Additionally, (Josiphos)Pd(CO)2 was identified as the catalyst resting state. A kinetic study suggests that the oxidative addition of aryl bromides is the turnover‐limiting step. Key catalytic intermediates were also isolated.
Carbene‐Catalyzed Intermolecular Dehydrogenative Coupling of Aldehydes with C(sp3)−H BondsSu, Fen; Zou, Juan; Lv, Xiaokang; Lu, Fengfei; Long, Yijie; Tang, Kun; Li, Benpeng; Chai, Huifang; Wu, Xingxing; Chi, Yonggui Robin
doi: 10.1002/anie.202303388pmid: 37016088
The development of catalyst‐controlled methods for direct functionalization of two distinct C−H bonds represents an appealing approach for C−C formations in synthetic chemistry. Herein, we describe an organocatalytic approach for straightforward acylation of C(sp3)−H bonds employing readily available aldehyde as “acyl source” involving dehydrogenative coupling of aldehydes with ether, amine, or benzylic C(sp3)−H bonds. The developed method affords a broad range of ketones under mild conditions. Mechanistically, simple ortho‐cyanoiodobenzene is essential in the oxidative radical N‐heterocyclic carbene catalysis to give a ketyl radical and C(sp3) radical through a rarely explored intermolecular hydrogen atom transfer pathway, rendering the acylative C−C formations in high efficiency under a metal‐ and light‐free catalytic conditions. Moreover, the prepared products show promising anti‐bacterial activities that shall encourage further investigations on novel agrochemical development.
X‐Ray‐triggered Carbon Monoxide and Manganese Dioxide Generation based on Scintillating Nanoparticles for Cascade Cancer RadiosensitizationDu, Zhen; Wang, Xin; Zhang, Xiao; Gu, Zhanjun; Fu, Xiaoyi; Gan, Shaoju; Fu, Ting; Xie, Sitao; Tan, Weihong
doi: 10.1002/anie.202302525pmid: 36930411
Carbon monoxide (CO) is an endogenous signaling molecule with broad therapeutic effects. Here, a multifunctional X‐ray‐triggered carbon monoxide (CO) and manganese dioxide (MnO2) generation nanoplatform based on metal carbonyl and scintillating nanoparticles (SCNPs) is reported. Attributed to the radioluminescent characteristic of SCNPs, UV‐responsive Mn2(CO)10 is not only indirectly activated to release CO by X‐ray but can also be degraded into MnO2. A high dose of CO can be used as a glycolytic inhibitor for tumor suppression; it will also sensitize tumor cells to radiotherapy. Meanwhile MnO2, as the photolytic byproduct of Mn2(CO)10, has both glutathione (GSH) depletion and Fenton‐like Mn2+ delivery properties to produce highly toxic hydroxyl radical (⋅OH) in tumors. Thus, this strategy can realize X‐ray‐activated CO release, GSH depletion, and ⋅OH generation for cascade cancer radiosensitization. Furthermore, X‐ray‐activated Mn2+ in vivo demonstrates an MRI contrast effect, making it a potential theranostic nanoplatform.