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Stereoselective Sensing of <scp>l</scp> - and <scp>d</scp> -Amino Acids: Development of a Fluorescence-Array Based on Readily Available Chiral Phosphoric Acids
摘要： A chiral sensor-array for the identification of amino-acids was developed, using six readily available bis- and tris-phosphoric acids in combination with Ni2 + and Eu3 +, resulting in a fluorescence-based array with twelve sensors. This array was successfully applied for the chemoselective identification of 19 amino-acids, but also for the enantioselective discrimination between the l- and d-enantiomers.
关键词： amino-acids,chiral sensor-array,fluorescence-based array,enantioselective discrimination,chemoselective identification
更新于2025-09-23 15:21:01
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Plasmon‐Enhanced InGaZnO Ultraviolet Photodetectors Tuned by Ferroelectric HfZrO
摘要： Allene (C3H4) gas is produced and separated on million-metric-ton scale per year during petroleum refining but is rarely employed in organic synthesis. Meanwhile, the addition of an allyl group (C3H5) to ketones is among the most common and prototypical reactions in synthetic chemistry. Herein, we report that the combination of allene gas with inexpensive and environmentally benign hydrosilanes, such as PMHS, can serve as a replacement for stoichiometric quantities of allylmetal reagents, which are required in most enantioselective ketone allylation reactions. This process is catalyzed by copper salts and commercially available ligands, operates without specialized equipment or pressurization, and tolerates a broad range of functional groups. Furthermore, the exceptional chemoselectivity of this catalyst system enables industrially relevant C3 hydrocarbon mixtures of allene with methylacetylene and propylene to be applied directly.
关键词： enantioselective allylation,allene,copper catalysis,hydrosilanes,petroleum cracking byproduct,ketones
更新于2025-09-19 17:13:59
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Photo‐Organocatalytic Enantioselective Radical Cascade Enabled by Single‐Electron Transfer Activation of Allenes
摘要： Allenes are commonly used in metal-mediated transformations, cycloaddition reactions, and radical processes. However, their activation by single-electron transfer (SET) is largely underexplored. Herein, we report a visible light-driven enantioselective organocatalytic process that uses the excited-state reactivity of chiral iminium ions to activate allenes by SET oxidation. The ensuing allene cation radicals participate in stereocontrolled cascade reactions to deliver bicyclic scaffolds with good enantioselectivity and exquisite diastereoselectivity. Density Functional Theory (DFT) calculations support a mechanism that combines the peculiar chemistry of allene radical cations with polar reactivity.
关键词： photochemistry,cascade process,allene,enantioselective organocatalysis,radical chemistry
更新于2025-09-19 17:13:59
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Observation of persistent orientation of chiral molecules by a laser field with twisted polarization
摘要： Molecular chirality is an omnipresent phenomenon of fundamental significance in physics, chemistry, and biology. For this reason, the search for various techniques for enantioselective control, detection, and separation of chiral molecules is of particular importance. It has been recently predicted that laser fields with twisted polarization may induce a persistent enantioselective field-free orientation of chiral molecules. Here, we report an experimental observation of this phenomenon using propylene oxide molecules (CH3CHCH2O, or PPO) spun by an optical centrifuge—a laser pulse—whose linear polarization undergoes an accelerated rotation around its propagation direction. We show that PPO molecules remain oriented on a timescale exceeding the duration of the centrifuge pulse by several orders of magnitude. The demonstrated long-time field-free enantioselective orientation may open new avenues for optical manipulation, discrimination, and, potentially, the separation of molecular enantiomers.
关键词： enantioselective control,persistent orientation,optical centrifuge,molecular chirality,propylene oxide
更新于2025-09-16 10:30:52
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Laser-induced persistent orientation of chiral molecules
摘要： We study, both classically and quantum mechanically, enantioselective orientation of gas-phase chiral molecules excited by laser fields with twisted polarization. Counterintuitively, the induced orientation, whose direction is laser controllable, does not disappear after the excitation but stays long after the end of the laser pulses. We computationally demonstrate this long-lasting orientation, using propylene oxide molecules (CH3CHCH2O, or PPO) as an example, and consider two kinds of fields with twisted polarization: a pair of delayed cross-polarized pulses and an optical centrifuge. This chiral effect opens avenues for detecting molecular chirality, measuring enantiomeric excess, and separating enantiomers with the help of inhomogeneous external fields.
关键词： laser-induced orientation,propylene oxide,chiral molecules,optical centrifuge,enantioselective
更新于2025-09-11 14:15:04
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Dissymmetry enhancement in enantioselective synthesis of helical polydiacetylene by application of superchiral light
摘要： Superchiral light, generated by the interference of two counter-propagating circularly polarized light (CPL) with same frequency, opposite handedness and different intensity, exhibits enhanced dissymmetry in its interaction with chiral molecules, and has the potential for ultrasensitive detection and characterization of chiral molecules. It is anticipated that the enhanced optical dissymmetry in superchiral light (SCL) field may be utilized to promote asymmetric photochemical reactions efficiency. Herein we reported SCL impart greater chiral bias to trigger asymmetric photo-polymerization reaction from initially achiral diacetylene (DA) monomer, and the enhanced optical dissymmetry for whole polydiacetylene (PDA) films could be achieved. An explanation based on the chiral transfer and amplification of chiral bias from SCL during the polymerization process has been proposed. Moreover, thus formed chiral PDA films polymerized by SCL exhibited enhanced enantioselective recognition ability, and can serve as a direct visual probe for the discrimination of some specific enantiomers.
关键词： polydiacetylene,asymmetric photochemical reactions,chiral molecules,enantioselective recognition,Superchiral light
更新于2025-09-10 09:29:36
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Photochemical generation of radicals from alkyl electrophiles using a nucleophilic organic catalyst
摘要： Chemists extensively use free radical reactivity for applications in organic synthesis, materials science, and life science. Traditionally, generating radicals requires strategies that exploit the bond dissociation energy or the redox properties of the precursors. Here, we disclose a photochemical catalytic approach that harnesses different physical properties of the substrate to form carbon radicals. We use a nucleophilic dithiocarbamate anion catalyst, adorned with a well-tailored chromophoric unit, to activate alkyl electrophiles via an SN2 pathway. The resulting photon-absorbing intermediate affords radicals upon homolytic cleavage induced by visible light. This catalytic SN2-based strategy, which exploits a fundamental mechanistic process of ionic chemistry, grants access to open-shell intermediates from a variety of substrates that would be incompatible with or inert to classical radical-generating strategies. We also describe how the method’s mild reaction conditions and high functional group tolerance could be advantageous for developing C–C bond-forming reactions, for streamlining the preparation of a marketed drug, for the late-stage elaboration of biorelevant compounds and for enantioselective radical catalysis.
关键词： radicals,SN2 pathway,alkyl electrophiles,photochemical,C–C bond-forming reactions,visible light,enantioselective radical catalysis,nucleophilic organic catalyst
更新于2025-09-10 09:29:36
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Enantioselective Allylic Alkylation with 4-Alkyl-1,4-dihydropyridines Enabled by Photoredox/Palladium Cocatalysis
摘要： Highly regio-, and enantioselective allylic alkylation has been achieved enabled by the merger of photoredox and palladium catalysis. In this dual catalytic process, alkyl radicals generated from 4-alkyl-1,4-dihydropyridines act as the coupling partners of the π-allyl palladium complexes. The generality of this method has been illustrated through the reaction of a variety of allyl esters with 4-alkyl-1,4-dihydropyridines. This mechanistically novel strategy expands the scope of the traditional Pd-catalyzed asymmetric allylic alkylation reaction and serves as its alternative and potential complement.
关键词： π-Allyl Palladium Complexes,Palladium Catalysis,4-Alkyl-1,4-dihydropyridines,Photoredox Catalysis,Enantioselective Allylic Alkylation
更新于2025-09-09 09:28:46