Synlett

Synlett 2024; 35: A165-A181DOI: 10.1055/s-0043-1764000Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents

Synlett 2024; 35: V-DOI: 10.1055/s-0043-1773497Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents

SynlettDOI: 10.1055/s-0043-1773496Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, GermanyArticle in Thieme eJournals:Table of contents  |  Full text

Adamantane-based methacrylates are important monomers for the design of polymers used for the development of chemically amplified photoresists. Herein, we present the selection of reaction conditions for obtaining of 2-ethyladamantan-2-yl methacrylate, 2-methyladamantan-2-yl methacrylate, adamantan-1-yl methacrylate, and 3-hydroxyadamantan-1-yl methacrylate from adamantane derivatives and methacryloyl chloride. It is shown that the combination of pyridine as a solvent and base with 1,4-diazabicyclo[2.2.2]octane (DABCO) as a base allows reproducible preparation of the desired products with good yields. The results obtained provide valuable information for upscaling the synthesis of important products for the microelectronics industry.

Here, we have reported a visible-light-mediated organic photoredox-catalyzed difunctionalization of vinyl arenes via radical–radical coupling. A stabilized benzylic radical at the α-position is generated via the regioselective addition of phosphonyl radical at the β-position of the styrene. Subsequently, benzyl or allyl radical, generated via the deaminative pathway from the Katritzky salt, combines with the α-radical of the styrene to furnish the functionalised C–P and C–C bonds in a single reaction.

Chemical-capture-mediated sensing has had a great impact on proteomic research. Toward this end, we demonstrate the chemical trapping of BSA by the reactive formyl functionality of a newly developed fluorescent nucleoside probe, formylphenothiazine-labeled-2′-deoxyuridine. The probe is capable of trapping BSA via Schiff base formation leading to fluorescence ‘switch-on’ sensing with a large hypsochromic shift of ca. 100 nm. The α-amylase does not show any significant change in fluorescence response, demonstrating the efficiency of the probe in selective sensing of BSA. Docking studies suggest the preferential interaction of the phenothiazinylcarbaldehyde-labeled dU with the residual amino acids in site I of the BSA protein as compared to site II.

The catalytic dehydrogenation of methanol to give formaldehyde or formic acid, followed transfer hydrogenation and/or tandem (de)hydrogenation for the hydrogenation and C-methylation of carbonyls, offers advantages over traditional methods, including milder reaction conditions, improved safety, greater selectivity, and enhanced sustainability. This account provides a comprehensive overview of homogeneous catalysts reported for the transfer hydrogenation and C-methylation of various substrates, including ketones, chalcones, esters, and amides, using methanol as both a hydrogen donor and methylation source. We provide specific examples and mechanistic insights for each strategy, offering a thorough and concise overview of recent advancements from 2014 to 2024.1 Introduction2 Methanol Activation Strategies3 Hydrogenation of Carbonyls4 Methylation of Carbonyls5 Outlook and Summary

We report an unprecedented synthesis of bis(pyrazolo[1,5-a]pyrimidin-3-yl)methanes, a new class of di(hetaryl)methanes, from pyrazolo[1,5-a]pyrimidines by using DMSO as a C1 synthon (methylene source). The transformation is mediated by sodium metabisulfite (Na2S2O5), which plays a crucial role in the presence of acetic acid as a promoter. A wide variety of bis(pyrazolo[1,5-a]pyrimidin-3-yl)methanes were synthesized in moderate to good yields of up to 90%. Mechanistic studies suggested that the reaction follows an ionic pathway, probably involving a methyl(methylene)sulfonium ion as an active electrophilic species formed in situ by the reaction of DMSO with Na2S2O5.

Tellurium is now recognized as a ‘technology-critical element’ that is quickly being used in innovative applications. The chemistry of organotellurium ligands has improved rapidly during the last three decades. Because of their enhanced accessibility and the possibility that they would display significantly different properties than their sulfur counterparts, these ligands of heavier chalcogens have sparked considerable attention. The next sections will go through the various tellurium ligands and associated transition-metal complexes. Organochalcogen ligands are exceedingly flexible ligands that may react with nearly any transition metal to form a wide range of compounds, including multidentate ligands.Tellurides of various metals have lately been investigated for potential use in storage devices, solar cells, piezoelectric, medical applications, electronics, photothermal treatment, nanoplatelets, nanocrystals, catalysis, and other fields. Researchers are interested in metal chalcogenide heterostructures because of their improved charge transport and synergistic optoelectronic and catalytic properties. A sensor for various metals based on Te electrodes and a donor ligand are used to generate electrical signals and identify different metals. Due to the scarcity of tellurium, metal telluride nanocrystal heterostructures have received less attention than metal sulfide and metal selenide nanocrystal heterostructures.1 Introduction2 Tellurenated Compounds of Zwitterionic Nature3 Synthesis of Tellurenated Ligands and Complexes4 Catalytic Application and and Suzuki–Miyara Coupling5 Tellurenated Sensors for Metal-Ion Sensing5.1 Tellurium-Ion Detectors5.2 Drawbacks/Catalyst Poisoning5.3 Disadvantages5.4 Advantages and Future Prospects6 Conclusions

The Birch reduction has found a renaissance during the last two decades. In this Synpacts article a short summary of selected recent synthetic applications will be provided. 1,4-Cyclohexadienes, which are formed by Birch reduction in one step, are suitable precursors for radical reactions and are used as surrogates for difficult-to-handle substances. Their rearomatization under acidic conditions offers easy access to selectively alkylated arenes. Additionally, the Birch reduction of benzoic acids and subsequent trapping afford spiro compounds in high yields. Very recently, it was shown that 1,3-cyclohexadienes are directly available by Birch reduction in a one-pot reaction as well.1 Introduction2 Rearomatizations3 Synthesis of Spiro Compounds4 Synthesis of 1,3-Cyclohexadienes5 Conclusion