Article
Chemistry, Organic
Sebastian Fischer, Terrence-Thang H. Nguyen, Andreas Ratzenboeck, Huw M. L. Davies, Oliver Reiser
Summary: A stereoselective, solvent- and metal-free method for endocyclic C-C bond cleavage of monocyclopropanated cyclopentadienes mediated by strong acids has been developed. It leads to the formation of highly functionalized six-membered carbocycles with high stereocontrol. The critical step involves the formation of a cyclopropyl carbocation that undergoes endocyclic ring opening through an SN2'-type attack of various nucleophiles. Subsequent synthetic transformations demonstrate the versatility of the resulting cyclohexenes for the synthesis of compounds with nonconventional substitution patterns.
Article
Polymer Science
Mohammed Ali Al Assiri, Eric Gomez Urreizti, Carlo Andrea Pagnacco, Estibaliz Gonzalez de San Roman, Fabienne Barroso-Bujans
Summary: B(C6F5)3 is a strong electrophilic catalyst that promotes the ring-opening polymerization of various epoxides. This synthetic route is a viable strategy for the generation of cyclic polyethers. A systematic study on the polymerization of glycidol with B(C6F5)3 revealed an abrupt chain growth at high monomer conversions. The formation of branched cyclic polyglycidols was observed, which exhibited lower glass transition temperatures compared to linear polyglycidols.
EUROPEAN POLYMER JOURNAL
(2022)
Article
Chemistry, Organic
Colby Barrett, Vinayak Krishnamurti, Xanath Ispizua-Rodriguez, Ziyue Zhu, Christopher J. Koch, G. K. Surya Prakash
Summary: An efficient and operationally simple method for the synthesis of gem-bromofluorocyclopropanes has been developed. The method uses ethyl dibromofluoroacetate as a cost-effective source of bromofluorocarbene intermediate. The protocol allows for the synthesis of bromofluorocyclopropane products with excellent yields, including examples synthesized in large scales.
Article
Chemistry, Organic
Tomohiro Kikuchi, Keiji Yamada, Takeshi Yasui, Yoshihiko Yamamoto
Summary: The metal-free ring expansion of cyclopropanols with a styrene moiety was achieved through a proton-coupled electron transfer enabled by an organic photoredox catalyst. Variants of 1-tetralone and 1-benzosuberone with a substituent at the benzylic position were selectively obtained through the regioselective ring closure of alkyl radical intermediates, depending on the substitution pattern of the alkene moiety.
Article
Chemistry, Multidisciplinary
Shuai Liu, Pengchen Ma, Lu Zhang, Shenyu Shen, Hong-Jie Miao, Le Liu, K. N. Houk, Xin-Hua Duan, Li-Na Guo
Summary: An efficient alkoxyl radical-triggered ring expansion/cross-coupling cascade was developed under cheap metal catalysis. A wide range of medium-sized lactones and macrolactones were constructed in moderate to good yields, along with diverse functional groups. The proposed catalytic cycle for this tandem reaction involves Cu(i)/Cu(ii)/Cu(iii).
Article
Chemistry, Inorganic & Nuclear
Thomas Buettner, Konstantin Weisshaar, Philipp Willmes, Volker Huch, Bernd Morgenstern, Rolf Hempelmann, David Scheschkewitz
Summary: The synthesis of p-methylthio-functionalized disilenes with (oligo)phenylene-linkers of different sizes was reported, with Si-29 NMR and UV/vis data suggesting that the linker-size only moderately affects the Si=Si moiety. Cyclic voltammetry showed an increasing number of reduction events with the number of phenylene rings, clearly associated with the oligo(phenylene) linking unit. Significant differences in the exchange current density of oxidation and reduction reactions were observed between the prepared disilenes using linear sweep voltammetry with a rotating disc electrode.
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
(2021)
Review
Polymer Science
Jordan Ochs, Carlo Andrea Pagnacco, Fabienne Barroso-Bujans
Summary: Cyclic polymers, with their circular structure and lack of chain ends, exhibit unique properties and potential applications. However, the preparation of high-purity cyclic polymers in large quantities remains challenging and requires continuous development of synthetic methods and techniques.
PROGRESS IN POLYMER SCIENCE
(2022)
Article
Chemistry, Organic
Tianyu Zhang, Han Zhuang, Luning Tang, Zhengyu Han, Wengang Guo, Hai Huang, Jianwei Sun
Summary: A novel intramolecular C-C formation process based on catalytic asymmetric oxetane opening by carbon nucleophiles has been developed, allowing for the rapid synthesis of valuable enantioenriched 2,3-dihydrobenzo[b]oxepines under mild conditions with good chemical efficiency and enantioselectivity. The products also serve as useful precursors to other valuable structures.
Article
Chemistry, Applied
Rui She, Jialin Qiu, Yan Liu, Yungui Peng
Summary: A synthetic method for the construction of 3-benzoxepin skeleton using a silver-catalyzed annulation/nucleophilic/ring-expansion reaction has been reported. This method yielded a series of 1-phosphonate-3-benzoxepin analogs in yields ranging from 39% to 95%. The resulting benzoxepins with halogen and phosphonate groups could be further modified into other derivatives.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Hans R. Kricheldorf, Steffen M. Weidner, Andreas Meyer
Summary: The alcohol-initiated ROPs of l-lactide at 160 degrees C for 72 hours produced high melting crystallites with melting temperatures of 189-193 degrees C, especially when using cyclic Sn(ii) compounds as catalysts. This suggests that the choice of catalyst can significantly impact the properties of the crystalline products.
Article
Chemistry, Multidisciplinary
Masato Tsuda, Taiki Morita, Hiroyuki Nakamura
Summary: This paper reports the synthesis of benzoisoxazoloborines via gold(I)-catalyzed propargyl azaClaisen rearrangement and electrophilic borylative cyclization. The in situ generation of aminoisoxazole intermediate with allenyl functionality is crucial for obtaining highly substituted compounds. Furthermore, the N-O bond insertion of a zinc carbenoid was used to synthesize oxazine-fused azaborine.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Haitao Liu, Feng Chen, Nannan Zhao, Sai V. C. Vummaleti, Michael B. Sullivan, Jackie Y. Ying, Lei Wang
Summary: Ring expansion reactions are efficient tools in synthetic and medicinal chemistry, but the strategy involving sulfur ylide-initiated [1,4]-sigmatropic rearrangement is still underexploited. In this study, a rhodium-catalyzed ring expansion of thiochromenes and aromatic thiophenes was disclosed, enabling the straightforward assembly of polyaromatic oxathionines and oxathiocines with diverse functionalities.
Article
Chemistry, Physical
Haitao Liu, Feng Chen, Nannan Zhao, Sai V. C. Vummaleti, Michael B. Sullivan, Jackie Y. Ying, Lei Wang
Summary: A rhodium-catalyzed ring expansion reaction has been discovered for the synthesis of polyaromatic oxathionines and oxathiocines with diverse functionalities.
Article
Chemistry, Multidisciplinary
Huan Luo, Junzhi Liu
Summary: Researchers developed a facile and effective method to synthesize a series of nitrogen-doped nanographenes in acceptable yields. Modification of the heptagonal ring endowed the resultant nanographenes with tunable physicochemical properties. Moreover, novel nanographenes containing nitrogen-doped pentagon-octagon pairs were obtained using the same synthetic strategy, demonstrating the superior versatility and efficiency of the proposed ring expansion method.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Jing Shang, Varsha J. Thombare, Carlie L. Charron, Uta Wille, Craig A. Hutton
Summary: The reaction of thiolactams with N-Boc amino acids promoted by Ag-I results in the formation of N-(alpha-aminoacyl) lactam, which can rearrange through an acyl transfer process. Deprotection of Boc leads to the ring expansion adduct, allowing for the insertion of an amino acid into the thioamide bond to generate medium-sized heterocycles. This method is demonstrated for the site-specific insertion of amino acids into cyclic peptides.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Paresh Kumar Majhi, Volker Huch, David Scheschkewitz
Summary: The synthesis and isolation of a stable potassium silagermenide compound with a Si=Ge bond as a suitable synthon for functional silagermenes has been reported. X-ray crystallographic analysis, UV/Vis spectroscopy, and DFT calculations confirmed a significant degree of pi-conjugation between N=C and Si=Ge double bonds in the compound.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Rosalyn L. Falconer, Gary S. Nichol, Ivan Smolyar, Scott L. Cockroft, Michael J. Cowley
Summary: This study presents a new class of organometallic compounds, dihydrodialanes supported by amidophosphine ligands. The ligand acts as a stereochemical reporter for reversible reductive elimination/oxidative addition chemistry involving Al-I and Al-III intermediates.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Lukas Klemmer, Anna-Lena Thoemmes, Michael Zimmer, Volker Huch, Bernd Morgenstern, David Scheschkewitz
Summary: The study reports thermally induced, transition-metal-free metathesis of unsymmetrically substituted digermenes. The use of tethered auxiliary donors helps stabilize the transient germylene fragments, promoting the metathesis reaction. Density functional theory calculations reveal the thermodynamic driving force of the metathesis and the crucial role of tethered donors in the reaction. The bridged tetragermadiene precursor can also undergo heavier acyclic diene metathesis polymerization, similar to the carbon case, resulting in polydigermene formation.
Review
Chemistry, Multidisciplinary
Yannic Heider, David Scheschkewitz
Summary: This review provides a comprehensive overview of the state of the art in the synthesis of molecular silicon clusters, which are divided into three different categories. It emphasizes the importance of functionalization as a necessary prerequisite for the design and construction of more extended systems.
Article
Chemistry, Multidisciplinary
Paresh Kumar Majhi, Michael Zimmer, Bernd Morgenstern, Volker Huch, David Scheschkewitz
Summary: Transition metal p-allyl complexes play important roles in various catalytic and stoichiometric allylation reactions. In this study, the first transition metal complex of a heavier allylic pi-system was reported, providing insights into the formation process and coordination behavior of the complex.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Paresh Kumar Majhi, Michael Zimmer, Bernd Morgenstern, David Scheschkewitz
Summary: A novel sesquimetallic complex containing a Si2Ge cyclopropene has been synthesized, showing a unique coordination mode where the sigma-component of the Ge = Si double bond acts as both a donor and acceptor, allowing for the formation of a nearly unsupported Si-Ge pi-bond. This complex can be easily modified and substituted with different functional groups, providing access to a variety of nickel complexes with high yields.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Inorganic & Nuclear
Andreas T. Kell, Naim M. Obeid, Prasenjit Bag, Michael Zimmer, Volker Huch, David Scheschkewitz
Summary: The regiodivergent reaction of phenylacetylene with various disilenes and bridged tetrasiladienes was studied, revealing that the regioselectivity of the [2+2] cycloaddition strongly depends on the nature of the substituent R. The presence of catalytic quantities of base suppresses cycloaddition in favor of the formal CH addition of phenylacetylene. Intermediacy of an alkynyl-substituted disilanyl lithium suggests a carbolithiation pathway for the net CH addition.
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
(2021)
Article
Chemistry, Inorganic & Nuclear
Marcel Lambert, Nadine E. Poitiers, Volker Huch, Andrea Goforth, David Scheschkewitz
Summary: The first silicon-carbon hybrid ladderanes with highly distorted ring systems and long silicon-carbon bridgehead bonds were obtained.
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
(2022)
Article
Chemistry, Multidisciplinary
Nadine E. Poitiers, Volker Huch, Bernd Morgenstern, Michael Zimmer, David Scheschkewitz
Summary: This study reports the growth of stable siliconoid clusters through a series of substitution, rearrangement, and reduction reactions with a single germanium atom. The findings are significant for understanding nucleation processes in gaseous and condensed phases.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Polymer Science
Hanna Huebner, Bart-Jan Niebuur, Thomas Buettner, Marcus Koch, Bernd Stuehn, Tobias Kraus, David Scheschkewitz, Markus Gallei
Summary: This study characterizes the self-assembled structures of PDMSB-b-P2VP block copolymer in different solvents and evaluates its response to different solvents and temperatures. The influence of additional solvents, temperature, and ultrasonication on colloidal dispersion is investigated. Additionally, the introduction of surfactants in the solvent evaporation method leads to a plethora of additional colloidal structures.
Article
Chemistry, Inorganic & Nuclear
Marc Hunsicker, Nadine E. Poitiers, Volker Huch, Bernd Morgenstern, Michael Zimmer, David Scheschkewitz
Summary: A new potential model system for silicon monoxide has been synthesized by connecting an unsaturated silicon cluster with a polyhedral silsequioxane cage. The stoichiometry between silicon and oxygen in this model system is 14:12.
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
(2022)
Article
Chemistry, Multidisciplinary
Philipp Dabringhaus, Silja Zedlitz, Luisa Giarrana, David Scheschkewitz, Ingo Krossing
Summary: Schnockel's [(AlCp*)(4)] and Jutzi's [SiCp*][B(C6F5)(4)] are important in modern main-group chemistry with various applications in synthesis and catalysis. However, the reactivity between AlCp* and [SiCp*](+) has not been explored. In this study, their reaction was investigated and complex salts [Cp*Si(AlCp*)(3)][WCA] were obtained. The tetrahedral [SiAl3](+) core not only represents a rare example of a low-valent silicon-doped aluminium-cluster, but also provides a convenient preparative entry towards low-valent Si-Al clusters.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Taiki Imagawa, Luisa Giarrana, Diego M. Andrada, Bernd Morgenstern, Masaaki Nakamoto, David Scheschkewitz
Summary: By a series of addition and reduction reactions, the synthesis of a structurally rare silapyramidane compound was achieved from an amidinate-supported silylene and tetrakis(trimethylsilyl)cyclobutadiene as starting materials. The silapyramidane compound exhibited an unusually shielded 29Si NMR resonance at -448.3 ppm for the apex silicon atom. Treatment of the silapyramidane with Fe2(CO)9 resulted in the formation of the corresponding silapyramidane-iron complex. Moreover, the silapyramidane also underwent a reaction with the cyclobutadiene starting material to afford a fluorescent spirobis(silole) compound.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Philipp Grewelinger, Tim Wiesmeier, Carsten Praesang, Bernd Morgenstern, David Scheschkewitz
Summary: A straightforward synthesis of the first peraryl diboriranide was reported, demonstrating its preference for s-type coordination modes towards main group and transition metal centers. The synthesis involved the preparation of the non-classical diborirane from a readily available 1,2-dichlorodiborane(4) and subsequent conversion to the peraryl diboriranide lithium salt in three steps. Representative complexes with tin, copper, gold, and zinc were prepared and characterized to illustrate the reactivity and complexation behavior of the diboriranide.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Inorganic & Nuclear
Thomas Buettner, Oliver Janka, Volker Huch, Debabrata Dhara, Anukul Jana, David Scheschkewitz
Summary: In this study, a new single source chemical vapor deposition (CVD) method was developed for the synthesis of binary iron-germanium thin films. The technique allows for the preparation of uniform and dense Fe(x)G(e)y films under standard CVD conditions, without the need for harsh conditions.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
