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Search for "kinetic" in Full Text gives 612 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Screwing the helical chirality through terminal peri-functionalization
- Devesh Chandra,
- Sachin and
- Upendra Sharma
Beilstein J. Org. Chem. 2026, 22, 205–212, doi:10.3762/bjoc.22.14
- through a catalytic kinetic resolution (KR) process was developed by Liu and co-workers [32]. The authors screened a range of organocatalysts, i.e., Takemoto’s thiourea catalyst, (S,S)-1,2-cyclohexanediamine-derived thioureas, cinchona alkaloid-derived thiourea, and squaramides to achieve the desired
- enantioselectivity. Notably, [6]helicene 3k was also readily produced, via kinetic resolution (Scheme 1). Computational studies suggested that hydrogen bonding and π interactions between the reactants and catalyst L1 controlled the stereochemical output of the products 3. The catalyst proximate both reactants to
- helical chiral entities was reported by Wang and co-workers. They reported an organocatalyzed asymmetric synthesis of phosphorus-containing chiral helicenes enabled by dynamic kinetic resolution using copper and peptide-mimetic phosphonium salts, i.e. amino acid-derived phosphonium iodide and bromide as
Graphical Abstract
Figure 1: Representation of the general practices for the induction of helical chirality in organic scaffolds...
Scheme 1: Asymmetric synthesis of carbohelicenes via peri-C–H functionalization.
Figure 2: Stereomodel for peri-terminal functionalization of carbohelicene. (Figure 2 was reproduced from [32] (© 2024 X....
Scheme 2: Scale-up synthesis and post-synthetic application of chiral helical product 3.
Scheme 3: Asymmetric peri-C–H functionalization of nitro-substituted oxa[5]helicenes.
Scheme 4: Scale-up synthesis and post-synthetic application of chiral helical product 8g.
Scheme 5: Post-synthetic transformation of product 8g to chiral phosphine ligand 12 and its application in Pd...
Figure 3: Stereomodel for the asymmetric peri-C–H functionalization of oxa[5]helicene. (Figure 3 was reproduced from [33]...
Improved synthesis and physicochemical characterization of the selective serotonin 2A receptor agonist 25CN-NBOH
- Adrian G. Rossebø,
- Hannah G. Kolberg,
- Anders E. Tønder,
- Louise Kjaerulff,
- Poul Erik Hansen,
- Karla A. Frydenvang,
- Jesper Østergaard and
- Jesper L. Kristensen
Beilstein J. Org. Chem. 2026, 22, 175–184, doi:10.3762/bjoc.22.11
- in water of 8.5 ± 0.3 mg/mL, leading to a solution with a pH of 6.24 ± 0.01. However, the kinetic solubility appears low; when preparing a solution of 5 mg/mL, the container must be shaken for several minutes. Previously, we reported the solubility of 1 in buffer at pH 7.4 to be 0.4 mg/mL, which is
Graphical Abstract
Figure 1: Synthesis of 25CN-NBOH·HCl (1·HCl). a) 2C-CN is available in 4 steps from 2C-H [12]: 1) TFAA, TEA, DCM;...
Figure 2: a) Single-crystal X-ray structure of 1·HCl. Displacement ellipsoids of the nonhydrogen atoms are sh...
Figure 3: SCXRD and XRPD spectra of different preparations of 1·HCl. Blue: SCXRD spectrum of 1·HCl. Red, gree...
Figure 4: TGA and DSC thermograms of 1·HCl.
Figure 5: Calculated pH-dependent species distribution curves for 25CN-NBOH (1).
Figure 6: a) Structure of the truncated model compound used for DFT calculations, with explicit water molecul...
Circumventing Mukaiyama oxidation: selective S–O bond formation via sulfenamide–alcohol coupling
- Guoling Huang,
- Huarui Zhu,
- Shuting Zhou,
- Wanlin Zheng,
- Fangpeng Liang,
- Zhibo Zhao,
- Yifei Chen and
- Xunbo Lu
Beilstein J. Org. Chem. 2026, 22, 158–166, doi:10.3762/bjoc.22.9
- previously disclosed a PIDA-mediated oxidative strategy for alcohol incorporation via activation of the S–NH bond (Scheme 1a) [14]. More recently, Wu and co-workers advanced the field by developing a dynamic kinetic resolution protocol for the enantioselective synthesis of sulfinimidate esters from racemic
- exceeds the theoretical maximum of 23% expected from the starting diastereomeric ratio, suggesting that the two diastereomers of 5 did not react at identical rates. These results are consistent with a partial kinetic resolution, wherein the major diastereomer of 5 reacts preferentially, leading to the
- reactivities of the two diastereomers. Although these findings strongly support the occurrence of a partial kinetic resolution, further kinetic measurements would be required for definitive confirmation. A plausible mechanism is outlined as follows. First, the sulfenamide 1 is oxidatively brominated by N
Graphical Abstract
Figure 1: Representative molecules containing a sulfilimine moiety.
Scheme 1: PIDA-mediated approach versus the present NBS-mediated approach to sulfinimidate esters.
Scheme 2: Substrate scope of sulfenamides derived from various thiophenols and thiols. Reaction conditions: s...
Scheme 3: Substrate scope of sulfenamides derived from various amides. Reaction conditions: sulfenamide 1 (0....
Scheme 4: Substrate scope of reactions between sulfenamides 1a and various alcohols. Reaction conditions: asu...
Scheme 5: Scale-up synthesis, late-stage derivatization, and substitution of diastereomeric sulfinimidate est...
Total synthesis of natural products based on hydrogenation of aromatic rings
- Haoxiang Wu and
- Xiangbing Qi
Beilstein J. Org. Chem. 2026, 22, 88–122, doi:10.3762/bjoc.22.4
- hydrogenation reaction (Scheme 7) [60]. Using an acid-assisted dynamic kinetic resolution method, they obtained a series of chiral indolines 56 containing exocyclic stereocenters in high yields and excellent enantioselectivity. Mechanistic studies of the reaction revealed that the dynamic kinetic resolution
- the reaction include high functional group tolerance and excellent stereocontrol. In the same year, Zhou and co-workers reported a rhodium/bisphosphine-catalyzed asymmetric hydrogenation reaction of all-carbon aromatic rings 69 (Scheme 8) [64]. Through desymmetrization or kinetic resolution, a series
- protonation during reduction or an isomerization event. Kinetic translocation of the double bond to the correct position enabled an intramolecular Heck reaction, a transformation originally developed by Fukuyama (Scheme 12) [78]. Hydrogenation of (−)-tabersonine to (−)-decahydrotabersonine by Catherine
Graphical Abstract
Scheme 1: The association between dearomatization and natural product synthesis.
Scheme 2: Key challenges in hydrogenation of aromatic rings.
Scheme 3: Hydrogenation of heterocyclic aromatic rings.
Scheme 4: Hydrogenation of the carbocyclic aromatic rings.
Scheme 5: Hydrogenation of the heterocycle part in bicyclic aromatic rings.
Scheme 6: Hydrogenation of the heterocycle part in bicyclic aromatic rings.
Scheme 7: Hydrogenation of benzofuran, indole, and their analogues.
Scheme 8: Hydrogenation of benzofuran, indole, and their analogues.
Scheme 9: Total synthesis of (±)-keramaphidin B by Baldwin and co-workers.
Scheme 10: Total synthesis of (±)-LSD by Vollhardt and co-workers.
Scheme 11: Total synthesis of (±)-dihydrolysergic acid by Boger and co-workers.
Scheme 12: Total synthesis of (±)-lysergic acid by Smith and co-workers.
Scheme 13: Hydrogenation of (−)-tabersonine to (−)-decahydrotabersonine by Catherine Dacquet and co-workers.
Scheme 14: Total synthesis of (±)-nominine by Natsume and co-workers.
Scheme 15: Total synthesis of (+)-nominine by Gin and co-workers.
Scheme 16: Total synthesis of (±)-lemonomycinone and (±)-renieramycin by Magnus.
Scheme 17: Total synthesis of GB13 by Sarpong and co-workers.
Scheme 18: Total synthesis of GB13 by Shenvi and co-workers.
Scheme 19: Total synthesis of (±)-corynoxine and (±)-corynoxine B by Xia and co-workers.
Scheme 20: Total synthesis of (+)-serratezomine E and the putative structure of huperzine N by Bonjoch and co-...
Scheme 21: Total synthesis of (±)-serralongamine A and the revised structure of huperzine N and N-epi-huperzin...
Scheme 22: Early attempts to indenopiperidine core.
Scheme 23: Homogeneous hydrogenation and completion of the synthesis.
Scheme 24: Total synthesis of jorunnamycin A and jorumycin by Stoltz and co-workers.
Scheme 25: Early attempt towards (−)-finerenone by Aggarwal and co-workers.
Scheme 26: Enantioselective synthesis towards (−)-finerenone.
Scheme 27: Total synthesis of (+)-N-methylaspidospermidine by Smith, Grigolo and co-workers.
Scheme 28: Dearomatization approach towards matrine-type alkaloids.
Scheme 29: Asymmetric total synthesis to (−)-senepodine F via an asymmetric hydrogenation of pyridine.
Scheme 30: Selective hydrogenation of indole derivatives and application.
Scheme 31: Synthetic approaches to the oxindole alkaloids by Qi and co-workers.
Scheme 32: Total synthesis of annotinolide B by Smith and co-workers.
Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review
- Daniel S. Müller
Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1
- attracted our interest, prompting a more detailed investigation. Kinetic studies with acetophenone revealed an induction period prior to reaction onset (Figure 5). Elevated temperatures shortened the initiation time, whereas lower temperatures extended it to several hours. Both temperature and reaction time
Graphical Abstract
Figure 1: Representative alkenyl chloride motifs in natural products. References: Pinnaic acid [8], haterumalide ...
Figure 2: Representative alkenyl chloride motifs in pharmaceuticals and pesticides. References: clomifene [25], e...
Figure 3: Graphical overview of previously published reviews addressing the synthesis of alkenyl chlorides.
Figure 4: Classification of synthetic approaches to alkenyl chlorides.
Scheme 1: Early works by Friedel, Henry, and Favorsky.
Scheme 2: Product distribution obtained by H NMR integration of crude compound as observed by Kagan and co-wo...
Scheme 3: Side reactions observed for the reaction of 14 with PCl5.
Scheme 4: Only compounds 15 and 18 were observed in the presence of Hünig’s base.
Scheme 5: Efficient synthesis of dichloride 15 at low temperatures.
Scheme 6: Various syntheses of alkenyl chlorides on larger scale.
Scheme 7: Scope of the reaction of ketones with PCl5 in boiling cyclohexane.
Scheme 8: Side reactions occur when using excess amounts of PCl5.
Scheme 9: Formation of versatile β-chlorovinyl ketones.
Scheme 10: Mixture of PCl5 and PCl3 used for the synthesis of 49.
Scheme 11: Catechol–PCl3 reagents for the synthesis of alkenyl chlorides.
Scheme 12: (PhO)3P–halogen-based reagents for the synthesis of alkenyl halides.
Scheme 13: Preparation of alkenyl chlorides from alkenyl phosphates.
Scheme 14: Preparation of alkenyl chlorides by treatment of ketones with the Vilsmeier reagent.
Scheme 15: Preparation of electron-rich alkenyl chlorides by treatment of ketones with the Vilsmeier reagent.
Scheme 16: Cu-promoted synthesis of alkenyl chlorides from ketones and POCl3.
Figure 5: GC yield of 9 depending on time and reaction temperature.
Figure 6: Broken reaction flask after attempts to clean the polymerized residue.
Figure 7: GC yield of 9 depending on the amount of CuCl and time.
Scheme 17: Treatment of 4-chromanones with PCl3.
Scheme 18: Synthesis of alkenyl chlorides from the reaction of ketones with acyl chlorides.
Scheme 19: ZnCl2-promoted alkenyl chloride synthesis.
Scheme 20: Regeneration of acid chlorides by triphosgene.
Scheme 21: Alkenyl chlorides from ketones and triphosgene.
Scheme 22: Various substitution reactions.
Scheme 23: Vinylic Finkelstein reactions reported by Evano and co-workers.
Scheme 24: Challenge of selective monohydrochlorination of alkynes.
Scheme 25: Sterically encumbered internal alkynes furnish the hydrochlorination products in high yield.
Scheme 26: Recent work by Kropp with HCl absorbed on alumina.
Scheme 27: High selectivities for monhydrochlorination with nitromethane/acetic acid as solvent.
Figure 8: Functionalized alkynes which typically afford the monhydrochlorinated products.
Scheme 28: Related chorosulfonylation and chloroamination reactions.
Scheme 29: Reaction of organometallic reagents with chlorine electrophiles.
Scheme 30: Elimination reactions of dichlorides to furnish alkenyl chlorides.
Scheme 31: Elimination reactions of allyl chloride 182 to furnish alkenyl chloride 183.
Scheme 32: Detailed studies by Schlosser on the elimination of dichloro compounds.
Scheme 33: Stereoselective variation caused by change of solvent.
Scheme 34: Elimination of gem-dichloride 189 to afford alkene 190.
Scheme 35: Oxidation of enones to dichlorides and in situ elimination thereof.
Scheme 36: Oxidation of allylic alcohols to dichlorides and in situ elimination thereof.
Scheme 37: Chlorination of styrenes with SOCl2 and elimination thereof.
Scheme 38: Chlorination of styrenes with SOCl2 and elimination thereof.
Scheme 39: Fluorine–chlorine exchange followed by elimination.
Scheme 40: Intercepting cations with alkynes and trapping of the alkenyl cation intermediate with chloride.
Scheme 41: Investigations by Mayr and co-workers.
Scheme 42: In situ activation of benzyl alcohol 230 with BCl3.
Scheme 43: In situ activation of benzylic alcohols with TiCl4.
Scheme 44: In situ activation of benzylic alcohols with FeCl3.
Scheme 45: In situ activation of benzylic alcohols with FeCl3.
Scheme 46: In situ activation of aliphatic chlorides and alcohols with ZnCl2, InCl3, and FeCl3.
Scheme 47: In situ generation of benzylic cations and trapping thereof with alkynes.
Scheme 48: Intramolecular trapping reactions affording alkenyl halides.
Scheme 49: Intramolecular trapping reactions affording alkenyl chlorides.
Scheme 50: Intramolecular trapping reactions of oxonium and iminium ions affording alkenyl chlorides.
Scheme 51: Palladium and nickel-catalyzed coupling reactions to afford alkenyl chlorides.
Scheme 52: Rhodium-catalyzed couplings of 1,2-trans-dichloroethene with arylboronic esters.
Scheme 53: First report on monoselective coupling reactions for 1,1-dichloroalkenes.
Scheme 54: Negishi’s and Barluenga’s contributions.
Scheme 55: First mechanistic investigation by Johnson and co-workers.
Scheme 56: First successful cross-metathesis with choroalkene 260.
Scheme 57: Subsequent studies by Johnson.
Scheme 58: Hoveyda and Schrock’s work on stereoretentive cross-metathesis with molybdenum-based catalysts.
Scheme 59: Related work with (Z)-dichloroethene.
Scheme 60: Further ligand refinement and traceless protection of functional groups with HBpin.
Scheme 61: Alkenyl chloride synthesis by Wittig reaction.
Scheme 62: Alkenyl chloride synthesis by Julia olefination.
Scheme 63: Alkenyl chloride synthesis by reaction of ketones with Mg/TiCl4 mixture.
Scheme 64: Frequently used allylic substitution reactions which lead to alkenyl chlorides.
Scheme 65: Enantioselective allylic substitutions.
Scheme 66: Synthesis of alkenyl chlorides bearing an electron-withdrawing group.
Scheme 67: Synthesis of α-nitroalkenyl chlorides from aldehydes.
Scheme 68: Synthesis of alkenyl chlorides via elimination of an in situ generated geminal dihalide.
Scheme 69: Carbenoid approach reported by Pace.
Scheme 70: Carbenoid approach reported by Pace.
Scheme 71: Ring opening of cyclopropenes in the presence of MgCl2.
Scheme 72: Electrophilic chlorination of alkenyl MIDA boronates to Z- or E-alkenyl chlorides.
Scheme 73: Hydroalumination and hydroboration of alkynyl chlorides.
Scheme 74: Carbolithiation of chloroalkynes.
Scheme 75: Chlorination of enamine 420.
Scheme 76: Alkyne synthesis by elimination of alkenyl chlorides.
Scheme 77: Reductive lithiation of akenyl chlorides.
Scheme 78: Reactions of alkenyl chlorides with organolithium reagents.
Scheme 79: Reactions of alkenyl chlorides with organolithium reagents.
Scheme 80: Addition–elimination reaction of alkenyl chloride 9 with organolithium reagents.
Scheme 81: C–H insertions of lithiumcarbenoids.
Scheme 82: Pd-catalyzed coupling reactions with alkenyl chlorides as coupling partner.
Scheme 83: Ni-catalyzed coupling of alkenylcopper reagent with alkenyl chloride 183.
Scheme 84: Ni-catalyzed coupling of heterocycle 472 with alkenyl chloride 473.
Scheme 85: Synthesis of α-chloroketones by oxidation of alkenyl chlorides.
Scheme 86: Tetrahalogenoferrate(III)-promoted oxidation of alkenyl chlorides.
Scheme 87: Chlorine–deuterium exchange promoted by a palladium catalyst.
Scheme 88: Reaction of alkenyl chlorides with thiols in the presence of AIBN (azobisisobutyronitrile).
Scheme 89: Chloroalkene annulation.
Recent advances in total synthesis of illisimonin A
- Juan Huang and
- Ming Yang
Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199
- reaction of 87 was employed, generating both the kinetic product 88 and the desired thermodynamic product 89. Heating 88 promoted a retro-Diels–Alder/Diels–Alder equilibrium, favoring the more stable isomer 89. Palladium-catalyzed hydrogenation of the 1,2-disubstituted alkene in 89, followed by Mo(CO)6
Graphical Abstract
Figure 1: The categorization of Illicium sesquiterpenes and representative natural products.
Figure 2: The original assigned (−)-illisimonin A, revised (−)-illisimonin A, and their different draws.
Scheme 1: Proposed biosynthetic pathway of illisimonin A by Yu et al.
Scheme 2: Rychnovsky’s racemic synthesis of illisimonin A (1).
Scheme 3: The absolute configuration revision of (−)-illisimonin A.
Scheme 4: Kalesse’s asymmetric synthesis of (−)-illisimonin A.
Scheme 5: Yang group proposed biosynthetic pathway of illisimonin A.
Scheme 6: Yang’s bioinspired synthesis of illisimonin A.
Scheme 7: Dai’s asymmetric synthesis of (–)-illisimonin A.
Scheme 8: Lu’s total synthesis of illisimonin A.
Scheme 9: Initial efforts toward the total synthesis of illisimonin A by the Lu Group.
Scheme 10: Suzuki’s synthetic effort towards illisimonin A.
Palladium-catalyzed regioselective C1-selective nitration of carbazoles
- Vikash Kumar,
- Jyothis Dharaniyedath,
- Aiswarya T P,
- Sk Ariyan,
- Chitrothu Venkatesh and
- Parthasarathy Gandeepan
Beilstein J. Org. Chem. 2025, 21, 2479–2488, doi:10.3762/bjoc.21.190
- that the cyclopalladation step is irreversible. To further investigate the nature of the C–H activation step, an intramolecular kinetic isotope effect (KIE) experiment was performed using monodeuterated substrate 1a-D1. A modest KIE value of kH/kD = 1.5 was observed under standard reaction conditions
Graphical Abstract
Scheme 1: (a) Representative examples of bioactive nitrocarbazoles. (b) Traditional electrophilic aromatic su...
Figure 1: ORTEP diagram of compound 2a (CCDC 2478298).
Scheme 2: Effect of directing groups on the nitration of the carbazoles.
Scheme 3: Scope of the method. Reaction conditions: 1 (0.2 mmol, 1.0 equiv), Pd2(dba)3 (0.02 mmol, 10 mol %),...
Scheme 4: Gram-scale synthesis, directing group removal, and synthetic utility of our method.
Scheme 5: Key mechanistic studies.
Figure 2: Plausible catalytic cycle.
Catalytic enantioselective synthesis of selenium-containing atropisomers via C–Se bond formations
- Qi-Sen Gao,
- Zheng-Wei Wei and
- Zhi-Min Chen
Beilstein J. Org. Chem. 2025, 21, 2447–2455, doi:10.3762/bjoc.21.186
- catalytic performance. The developed catalytic system demonstrated high activity, excellent yields (mostly exceeding 85%), mild reaction conditions, broad functional group tolerance, as well as high regioselectivity, (E)-selectivity, and enantioselectivity (up to 99% ee). According to the kinetic study, the
Graphical Abstract
Figure 1: Representative examples of chiral selenium-containing compounds.
Scheme 1: Rhodium-catalyzed atroposelective C–H selenylation reported by You’s group [18].
Scheme 2: Rhodium-catalyzed atroposelective C–H selenylation reported by Li et al. [19].
Scheme 3: Organocatalytic asymmetric selenosulfonylation of alkynes.
Scheme 4: Rhodium-catalyzed asymmetric hydroselenation of 1-alkynylindoles. *DCE/DCM 2:1 (v/v), −50 °C.
Scheme 5: Organocatalytic atroposelective hydroselenation of alkynes. *Using cat.3, 4 h.
Adaptive experimentation and optimization in organic chemistry
- Artur M. Schweidtmann and
- Philippe Schwaller
Beilstein J. Org. Chem. 2025, 21, 2367–2368, doi:10.3762/bjoc.21.180
- . provide a comprehensive review of machine learning applications in enantioselective organocatalysis, highlighting both achievements and remaining challenges [10]. Guo et al. present an automated flow chemistry system for nitration reactions, combining kinetic modeling with experimental optimization [11
Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications
- Jullyane Emi Matsushima,
- Khushbu,
- Zuliah Abdulsalam,
- Udyogi Navodya Kulathilaka Conthagamage and
- Víctor García-López
Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179
- pyridinium site. This light-driven shuttling was shown to be fatigue-resistant over multiple cycles, highlighting the robustness of the system. Notably, the authors also reported a general quantification of kinetic asymmetry in a multicycle chemical reaction network, establishing a framework applicable to
Graphical Abstract
Figure 1: Schematic of common rotaxanes (left) and depiction of the macrocycle shuttling (right).
Figure 2: Structure of some common photoswitches integrated into rotaxanes.
Figure 3: Rotaxane with an acridane photoswitch on the axle modulates the translation of a CBQT4+ macrocycle ...
Figure 4: Hydrogel composed of [2]rotaxanes featuring a central azobenzene in the axle and a cyclodextrin mac...
Figure 5: Dendrimer composed of [2]rotaxane with an azobenzene photoswitch functioning as a macroscopic actua...
Figure 6: (a) Structure of the [2]rotaxane and (b) mechanism for K+ cations transport across lipid bilayers. Figure 6...
Figure 7: Dithienylethene-based [2]rotaxane used in writing patterning applications: (a) rotaxane with open d...
Figure 8: Dithienylethene-based [1]rotaxane shuttling motion triggered by pH changes (top). Dithienylethene p...
Figure 9: Depiction of a fumaramide-based [2]rotaxane photoswitching cycle and deposition on glass and mica s...
Figure 10: Hydrazone-based rotaxane controls helical pitch in a liquid crystal. Figure 10 was adapted from [73] (© 2024 S. ...
Figure 11: (a) Light- and pH-responsive Förster resonance energy transfer observed on a spiropyran-based [2]ro...
Figure 12: Photoresponsive bending of artificial muscle with [c2]daisy chain reported by Harada and collaborat...
Figure 13: Light-responsive shuttling motion of [2]rotaxane based on a stiff-stilbene photoswitch. Figure 13 was reprod...
Figure 14: Azobenzene-based rotaxane modulating lipid bilayers upon photoisomerization. Figure 14 was adapted from [23] (© ...
Figure 15: Depiction of fluorescence quenching processes upon external stimuli of a dithienylethene-based [2]r...
Figure 16: Diagrammatic illustration of rotaxane 1-H-SP depicting interconversions between the four isomeric s...
Figure 17: Representation of [2]rotaxane chloride binding modulated by photoisomerization of a stiff-stilbene. ...
Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes
- Suvenika Perera,
- Peter Y. Zavalij and
- Lyle Isaacs
Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176
- (20 mg) is used. Kinetic studies conducted for both hosts H2 and G2W1 in the removal of methylene blue and methylene violet, respectively, demonstrate a rapid sequestration process that reaches a plateau within 30 minutes. In conclusion, this study highlights the importance of avoiding host structural
Graphical Abstract
Figure 1: Chemical structures of selected hosts used as the basis for sequestrants.
Scheme 1: a) Synthesis of triphenylene-derived aromatic walls W1 and W2, and b) structure of commercially ava...
Scheme 2: Synthesis of methylene-bridged glycoluril dimers G2W1–G2W4. Conditions: a) TFA: Ac2O, 95 °C, 3.5 h (...
Figure 2: Chemical structures of dyes used in this study.
Figure 3: 1H NMR spectra recorded (400 MHz, DMSO-d6, rt) for: a) G2W1, b) G2W2, c) G2W3, d) G2W4.
Figure 4: Plot of removal efficiency of dyes from water after incubating with equimolar amounts (7.2 μmol) of ...
Figure 5: Cross-eyed stereoview of: a) one molecule of G2W3 in the crystal, and b) the packing of G2W3 in the...
Figure 6: Cross-eyed stereoview of: a) a molecule of G2W1 in the crystal, b) the packing of G2W1 along the xz...
Figure 7: a) Plot of removal efficiency of methylene blue (240 μM, 1 mL) from water after incubating with dif...
Figure 8: Plot of the removal efficiency versus methylene blue concentration (70, 90, 120, 180, 240, 300, 100...
Figure 9: a) Plot of removal efficiency of methylene blue (240 μM, 1 mL) from water as a function of time aft...
Halogenated butyrolactones from the biomass-derived synthon levoglucosenone
- Johannes Puschnig,
- Martyn Jevric and
- Ben W. Greatrex
Beilstein J. Org. Chem. 2025, 21, 2297–2301, doi:10.3762/bjoc.21.175
- oxymethylene bridge in the 2D NOESY NMR spectrum. Given the instability of fluoro-ketone 13, a one-pot procedure was developed in which the reaction mixture containing 13 was subjected to the Baeyer–Villiger oxidation with H2O2 giving the fluorinated and stable lactone 14, which is the expected kinetic product
Graphical Abstract
Figure 1: Halogen-containing butyrolactone-derived bioactives.
Scheme 1: Preparation of chlorinated and brominated lactones 8a,b and 11a,b.
Scheme 2: Preparation of fluorinated lactone 14.
Scheme 3: Fluorination of LGO (5) and conversion to lactone 17.
Scheme 4: Trifluoromethylation of 9a,b and 15 and subsequent Baeyer–Villiger oxidation.
Pathway economy in cyclization of 1,n-enynes
- Hezhen Han,
- Wenjie Mao,
- Bin Lin,
- Maosheng Cheng,
- Lu Yang and
- Yongxiang Liu
Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173
- regulatory role in chemical transformations, exerting kinetic modulation through solvation effects on activation barriers and reaction rates, dictating thermodynamic equilibria that govern product distribution, and enabling precise reaction pathway regulation via selective stabilization of critical
- control principles for gold catalysis. Temperature-controlled cyclization of 1,n-enynes Temperature, a pivotal thermodynamic parameter, not only governs reaction kinetics but also determines reaction pathways. Typically, kinetic product formation is favored at lower temperatures via pathways with reduced
Graphical Abstract
Scheme 1: Economical synthesis and pathway economy.
Scheme 2: Au(I)-catalyzed cascade cyclization paths of 1,5-enynes.
Scheme 3: Au(I)-catalyzed cyclization paths of 1,7-enynes.
Scheme 4: I2/TBHP-mediated radical cycloisomerization paths of 1,n-enyne.
Scheme 5: Au(I)-catalyzed cycloisomerization paths of 3-allyloxy-1,6-diynes.
Scheme 6: Pd(II)-catalyzed cycloisomerization paths of 2-alkynylbenzoate-cyclohexadienone.
Scheme 7: Stereoselective cyclization of 1,5-enynes.
Scheme 8: Substituent-controlled cycloisomerization of propargyl vinyl ethers.
Scheme 9: Au(I)-catalyzed pathway-controlled domino cyclization of 1,2-diphenylethynes.
Scheme 10: Au(I)-catalyzed tandem cyclo-isomerization of tryptamine-N-ethynylpropiolamide.
Scheme 11: Au(I)-catalyzed tunable cyclization of 1,6-cyclohexenylalkyne.
Scheme 12: Substituent-controlled 7-exo- and 8-endo-dig-selective cyclization of 2-propargylaminobiphenyl deri...
Scheme 13: BiCl3-catalyzed cycloisomerization of tryptamine-ynamide derivatives.
Scheme 14: Au(I)-mediated substituent-controlled cycloisomerization of 1,6-enynes.
Scheme 15: Ligand-controlled regioselective cyclization of 1,6-enynes.
Scheme 16: Ligand-dependent cycloisomerization of 1,7-enyne esters.
Scheme 17: Ligand-controlled cycloisomerization of 1,5-enynes.
Scheme 18: Ligand-controlled cyclization strategy of alkynylamide tethered alkylidenecyclopropanes.
Scheme 19: Ag(I)-mediated pathway-controlled cycloisomerization of tryptamine-ynamides.
Scheme 20: Gold-catalyzed cycloisomerization of indoles with alkynes.
Scheme 21: Catalyst-dependent cycloisomerization of dienol silyl ethers.
Scheme 22: Cycloisomerization of aromatic enynes governed by catalyst.
Scheme 23: Catalyst-dependent 1,2-migration in cyclization of 1-(indol-2-yl)-3-alkyn-1-ols.
Scheme 24: Gold-catalyzed cycloisomerization of N-propargyl-N-vinyl sulfonamides.
Scheme 25: Gold(I)-mediated enantioselective cycloisomerizations of ortho-(alkynyl)styrenes.
Scheme 26: Catalyst-controlled intramolecular cyclization of 1,7-enynes.
Scheme 27: Brønsted acid-catalyzed cycloisomerizations of tryptamine ynamides.
Scheme 28: Catalyst-controlled cyclization of indolyl homopropargyl amides.
Scheme 29: Angle strain-dominated 6-endo-trig cyclization of propargyl vinyl ethers.
Scheme 30: Angle strain-controlled cycloisomerization of alkyn-tethered indoles.
Scheme 31: Geometrical isomeration-dependent cycloisomerization of 1,3-dien-5-ynes.
Scheme 32: Temperature-controlled cyclization of 1,7-enynes.
Scheme 33: Cycloisomerizations of n-(o-ethynylaryl)acrylamides through temperature modulation.
Scheme 34: Temperature-controlled boracyclization of biphenyl-embedded 1,3,5-trien-7-ynes.
Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates
- Gyöngyvér Pusztai,
- László Poszávácz,
- Anna Vincze,
- András Marton,
- Ahmed Qasim Abdulhussein,
- Judit Halász,
- András Dancsó,
- Gyula Simig,
- György Tibor Balogh and
- Balázs Volk
Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169
- physicochemical and early ADME characterization study, in the framework of which logP, pKa and logk values were calculated. Following that, kinetic solubility and in vitro gastrointestinal membrane-specific permeability measurements were carried out to assess the lead-likeness of the compounds. Subsequently, the
- results of physicochemical and early ADME characterization for hydrazones 7 and 9, and target compounds 3 and 10 are summarized in Table 2 and Table 3, respectively (individual column charts on kinetic solubility, permeability, and membrane retention measurements can be found in Supporting Information
- surface area (TPSA) values fell in a desirable range (40–90 Å2) (see the extended table on physicochemical parameters in Supporting Information File 1, Table S1). Based on their pKa values, all compounds are non-ionizable or slightly basic. Kinetic solubility was considered good above 30 µM, moderate
Graphical Abstract
Figure 1: Phthalazinones 1, benzothiadiazine dioxides 2, and thiadiazinoindole dioxides 3.
Scheme 1: Synthesis of tri- and tetracyclic thiadiazinoindole dioxides 3.
Figure 2: 1H NMR and selective 1D NOESY (with the excitation of NH) spectra of (E)-7h.
Figure 3: 1H NMR and selective 1D NOESY (with the excitation of NH) spectra of (Z)-7h.
Scheme 2: Synthesis of pentacyclic compounds 10.
Figure 4: X-ray structures of compounds 3d (A), 7d (B), (Z)-7h (C), and (E)-9a (D).
Figure 5: The capacity factor (logk) vs calculated partition coefficients (clogP) by ACD Labs/Percepta [36]); the...
C2 to C6 biobased carbonyl platforms for fine chemistry
- Jingjing Jiang,
- Muhammad Noman Haider Tariq,
- Florence Popowycz,
- Yanlong Gu and
- Yves Queneau
Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165
- 50% yield and 99% ee after kinetic resolution using Escherichia coli (Scheme 57) [189]. Other reactions: Yamamoto synthesized 6-hydroxy-2-(trifluoromethyl)-2H-pyran-3(6H)-ones from furfural via trifluoromethylation using the Ruppert–Prakash reagent (TMSCF3), followed by a photo-Achmatowicz reaction
Graphical Abstract
Figure 1: C2–C6 biobased carbonyl building blocks.
Scheme 1: Proposed (2 + 2) route to glycolaldehyde and glycolic acid from erythritol by Cu/AC catalyst (AC = ...
Scheme 2: Reductive amination of GCA.
Scheme 3: N-Formylation of secondary amines by reaction with GCA.
Scheme 4: Synthesis and conversion of hydroxy acetals to cyclic acetals.
Scheme 5: Synthesis of 3-(indol-3-yl)-2,3-dihydrofurans via three-component reaction of glycolaldehyde, indol...
Scheme 6: BiCl3-catalyzed synthesis of benzo[a]carbazoles from 2-arylindoles and α-bromoacetaldehyde ethylene...
Scheme 7: Cu/NCNSs-based conversion of glycerol to glycolic acid and other short biobased acids.
Scheme 8: E. coli-based biotransformation of C1 source molecules (CH4, CO2 and CO) towards C2 glycolic acid.
Scheme 9: N-Formylation of amines with C2 (a) or C3 (b) biomass-based feedstocks.
Scheme 10: Methods for the formation of propanoic acid (PA) from lactic acid (LA).
Scheme 11: Co-polymerization of biobased lactic acid and glycolic acid via a bicatalytic process.
Scheme 12: Oxidation of α-hydroxy acids by tetrachloroaurate(III) in acetic acid–sodium acetate buffer medium.
Figure 2: Selective catalytic pathways for the conversion of lactic acid (LA).
Scheme 13: Synthesis of 1,3-PDO via cross-aldol reaction between formaldehyde and acetaldehyde to 3-hydroxypro...
Scheme 14: Hydrothermal conversion of 1,3-dihydroxy-2-propane and 2,3-dihydroxypropanal to methylglyoxal.
Scheme 15: FLS-catalyzed formose reaction to synthesize GA and DHA.
Scheme 16: GCA and DHA oxidation products of glycerol and isomerization of GCA to DHA under flow conditions us...
Scheme 17: Acid-catalyzed reactions of DHA with alcohols.
Scheme 18: Synthesis of dihydroxyacetone phosphate from dihydroxyacetone.
Scheme 19: Bifunctional acid–base catalyst DHA conversion into lactic acid via pyruvaldehyde or fructose forma...
Scheme 20: Catalytic one-pot synthesis of GA and co-synthesis of formamides and formates from DHA.
Scheme 21: (a) Synthesis of furan derivatives and (b) synthesis of thiophene derivative by cascade [3 + 2] ann...
Scheme 22: Brønsted acidic ionic liquid catalyzed synthesis of benzo[a]carbazole from renewable acetol and 2-p...
Scheme 23: Asymmetric hydrogenation of α-hydroxy ketones to 1,2-diols.
Scheme 24: Synthesis of novel 6-(substituted benzylidene)-2-methylthiazolo [2,3-b]oxazol-5(6H)-one from 1-hydr...
Scheme 25: ʟ-Proline-catalyzed synthesis of anti-diols from hydroxyacetone and aldehydes.
Scheme 26: C–C-bond-formation reactions of a biomass-based feedstock aromatic aldehyde (C5) and hydroxyacetone...
Scheme 27: Ethanol upgrading to C4 bulk chemicals via the thiamine (VB1)-catalyzed acetoin condensation.
Scheme 28: One-pot sequential chemoenzymatic synthesis of 2-aminobutane-1,4-diol and 1,2,4-butanetriol via 1,4...
Scheme 29: Synthesis of 1,4-dihydroxybutan-2-one by microbial transformation.
Scheme 30: Conversion of polyols by [neocuproine)Pd(OAc)]2(OTf)2] to α-hydroxy ketones.
Scheme 31: Chemoselective oxidation of alcohols with chiral palladium-based catalyst 2.
Scheme 32: Electrochemical transformation of furfural to 5-hydroxy-2(5H)-furanone (HFO).
Scheme 33: Selective hydrodeoxygenation of HFO and oxidation to γ-butyrolactone (GBL).
Scheme 34: Photosensitized oxygenation of furan towards HFO via ozonide intermediates.
Scheme 35: Conversion of furfural to HFO and MAN by using mesoporous carbon nitride (SGCN) as photocatalyst.
Scheme 36: Synthesis of HFO from furan derivatives.
Scheme 37: Photooxidation of furfural to 5-hydroxy-2(5H)-furanone (HFO).
Scheme 38: Synthesis of Friedel–Crafts indole adduct from HFO.
Scheme 39: Conversion of HFO to α,γ-substituted chiral γ-lactones.
Scheme 40: Tautomeric transformation of HFO to formylacrylic acid.
Scheme 41: Hydrolysis of HFO to succinic acid in aqueous solution.
Scheme 42: Substitution and condensation reactions of 5-hydroxy-2(5H)-furanone (HFO).
Scheme 43: (a) Conversion of HFO towards valuable C4 chemicals and (b) anodic oxidation of 5-hydroxy-2(5H)-fur...
Figure 3: Conversion of HFO towards other natural and synthetic substances.
Scheme 44: Conversion of furfural to maleic anhydride (reaction a: VOx/Al2O3; reaction b: VPO).
Scheme 45: Conversion of furfural into succinic acid.
Scheme 46: Electro‑, photo‑, and biocatalysis for one-pot selective conversions of furfural into C4 chemicals.
Scheme 47: Production route of furfural from hemicellulose.
Scheme 48: Mechanism for xylose dehydration to furfural through a choline xyloside intermediate.
Scheme 49: Conversion of furfural to furfuryl alcohol and its derivatives.
Scheme 50: Conversion of furfural to furfuryl alcohol and 3-(2-furyl)acrolein.
Scheme 51: The aerobic oxidative condensation of biomass-derived furfural and linear alcohols.
Scheme 52: The single-step synthesis of 2-pentanone from furfural.
Scheme 53: Electrocatalytic coupling reaction of furfural and levulinic acid.
Scheme 54: Conversion of furfural to m-xylylenediamine.
Scheme 55: Conversion of furfural to tetrahydrofuran-derived amines.
Scheme 56: Formation of trans-4,5-diamino-cyclopent-2-enones from furfural.
Scheme 57: Production of pyrrole and proline from furfural.
Scheme 58: Synthesis of 1‑(trifluoromethyl)-8-oxabicyclo[3.2.1]oct-3-en-2-ones from furfural.
Scheme 59: Conversion of furfural to furfural-derived diacids.
Scheme 60: A telescope protocol derived from furfural and glycerol.
Scheme 61: A tandem cyclization of furfural and 5,5-dimethyl-1,3-cyclohexanedione.
Scheme 62: A Ugi four-component reaction to construct furfural-based polyamides.
Scheme 63: One-pot synthesis of γ-acyloxy-Cy7 from furfural.
Scheme 64: Dimerization–Piancatelli sequence toward humins precursors from furfural.
Scheme 65: Conversion of furfural to CPN.
Scheme 66: Synthesis of jet fuels range cycloalkanes from CPN and lignin-derived vanillin.
Scheme 67: Solar-energy-driven synthesis of high-density biofuels from CPN.
Scheme 68: Reductive amination of CPN to cyclopentylamine.
Scheme 69: Asymmetric hydrogenation of C=O bonds of exocyclic α,β-unsaturated cyclopentanones.
Scheme 70: Preparation of levulinic acid via the C5 route (route a) or C6 route (routes b1 and b2).
Scheme 71: Mechanism of the rehydration of HMF to levulinic acid and formic acid.
Scheme 72: Important levulinic acid-derived chemicals.
Scheme 73: Direct conversion of levulinic acid to pentanoic acid.
Scheme 74: Catalytic aerobic oxidation of levulinic acid to citramalic acid.
Scheme 75: Conversion of levulinic acid to 1,4-pentanediol (a) see ref. [236]; b) see ref. [237]; c) see ref. [238]; d) see r...
Scheme 76: Selective production of 2-butanol through hydrogenolysis of levulinic acid.
Scheme 77: General reaction pathways proposed for the formation of 5MPs from levulinic acid.
Scheme 78: Selective reductive amination of levulinic acid to N-substituted pyrroles.
Scheme 79: Reductive amination of levulinic acid to chiral pyrrolidinone.
Scheme 80: Reductive amination of levulinic acid to non-natural chiral γ-amino acid.
Scheme 81: Nitrogen-containing chemicals derived from levulinic acid.
Scheme 82: Preparation of GVL from levulinic acid by dehydration and hydrogenation.
Scheme 83: Ruthenium-catalyzed levulinic acid to chiral γ-valerolactone.
Scheme 84: Catalytic asymmetric hydrogenation of levulinic acid to chiral GVL.
Scheme 85: Three steps synthesis of ε-caprolactam from GVL.
Scheme 86: Multistep synthesis of nylon 6,6 from GVL.
Scheme 87: Preparation of MeGVL by α-alkylation of GVL.
Scheme 88: Ring-opening polymerization of five-membered lactones.
Scheme 89: Synthesis of GVL-based ionic liquids.
Scheme 90: Preparation of butene isomers from GVL under Lewis acid conditions.
Scheme 91: Construction of C5–C12 fuels from GVL over nano-HZSM-5 catalysts.
Scheme 92: Preparation of alkyl valerate from GVL via ring opening/reduction/esterification sequence.
Scheme 93: Construction of 4-acyloxypentanoic acids from GVL.
Scheme 94: Synthesis of 1,4-pentanediol (PDO) from GVL.
Scheme 95: Construction of novel cyclic hemiketal platforms via self-Claisen condensation of GVL.
Scheme 96: Copper-catalyzed lactamization of GVL.
Figure 4: Main scaffolds obtained from HMF.
Scheme 97: Biginelli reactions towards HMF-containing dihydropyrimidinones.
Scheme 98: Hantzsch dihydropyridine synthesis involving HMF.
Scheme 99: The Kabachnik–Fields reaction involving HMF.
Scheme 100: Construction of oxazolidinone from HMF.
Scheme 101: Construction of rhodamine-furan hybrids from HMF.
Scheme 102: A Groebke–Blackburn–Bienaymé reaction involving HMF.
Scheme 103: HMF-containing benzodiazepines by [4 + 2 + 1] cycloadditions.
Scheme 104: Synthesis of fluorinated analogues of α-aryl ketones.
Scheme 105: Synthesis of HMF derived disubstituted γ-butyrolactone.
Scheme 106: Functionalized aromatics from furfural and HMF.
Scheme 107: Diels–Alder adducts from HMF or furfural with N-methylmaleimide.
Scheme 108: Pathway of the one-pot conversion of HMF into phthalic anhydride.
Scheme 109: Photocatalyzed preparation of humins (L-H) from HMF mixed with spoiled HMF residues (LMW-H) and fur...
Scheme 110: Asymmetric dipolar cycloadditions on HMF.
Scheme 111: Dipolar cycloadditions of HMF based nitrones to 3,4- and 3,5-substituted isoxazolidines.
Scheme 112: Production of δ-lactone-fused cyclopenten-2-ones from HMF.
Scheme 113: Aza-Piancatelli access to aza-spirocycles from HMF-derived intermediates.
Scheme 114: Cross-condensation of furfural, acetone and HMF into C13, C14 and C15 products.
Scheme 115: Base-catalyzed aldol condensation/dehydration sequences from HMF.
Scheme 116: Condensation of HMF and active methylene nitrile.
Scheme 117: MBH reactions involving HMF.
Scheme 118: Synthesis of HMF-derived ionic liquids.
Scheme 119: Reductive amination/enzymatic acylation sequence towards HMF-based surfactants.
Scheme 120: The formation of 5-chloromethylfurfural (CMF).
Scheme 121: Conversion of CMF to HMF, levulinic acid, and alkyl levulinates.
Scheme 122: Conversion of CMF to CMFCC and FDCC.
Scheme 123: Conversion of CMF to BHMF.
Scheme 124: Conversion of CMF to DMF.
Scheme 125: CMF chlorine atom substitutions toward HMF ethers and esters.
Scheme 126: Introduction of carbon nucleophiles in CMF.
Scheme 127: NHC-catalyzed remote enantioselective Mannich-type reactions of CMF.
Scheme 128: Conversion of CMF to promising biomass-derived dyes.
Scheme 129: Radical transformation of CMF with styrenes.
Scheme 130: Synthesis of natural herbicide δ-aminolevulinic acid from CMF.
Scheme 131: Four step synthesis of the drug ranitidine from CMF.
Scheme 132: Pd/CO2 cooperative catalysis for the production of HHD and HXD.
Scheme 133: Different ruthenium (Ru) catalysts for the ring-opening of 5-HMF to HHD.
Scheme 134: Proposed pathways for preparing HXD from HMF.
Scheme 135: MCP formation and uses.
Scheme 136: Cu(I)-catalyzed highly selective oxidation of HHD to 2,5-dioxohexanal.
Scheme 137: Synthesis of N‑substituted 3‑hydroxypyridinium salts from 2,5-dioxohexanal.
Scheme 138: Ru catalyzed hydrogenations of HHD to 1,2,5-hexanetriol (a) see ref. [396]; b) see ref. [397]).
Scheme 139: Aviation fuel range quadricyclanes produced by HXD.
Scheme 140: Synthesis of HDGK from HXD and glycerol as a chain extender.
Scheme 141: Synthesis of serinol pyrrole from HXD and serinol.
Scheme 142: Synthesis of pyrroles from HXD and nitroarenes.
Scheme 143: Two-step production of PX from cellulose via HXD.
Scheme 144: Preparation of HCPN from HMF via hydrogenation and ring rearrangement.
Scheme 145: Suggested pathways from HMF to HCPN.
Scheme 146: α-Alkylation of HCPN with ethylene gas.
Scheme 147: Synthesis of 3-(hydroxymethyl)cyclopentylamine from HMF via reductive amination of HCPN.
Scheme 148: Production of LGO and Cyrene® from biomass.
Scheme 149: Synthesis of HBO from LGO and other applications.
Scheme 150: Construction of m-Cyrene® homopolymer.
Scheme 151: Conversion of Cyrene® to THFDM and 1,6-hexanediol.
Scheme 152: RAFT co-polymerization of LGO and butadienes.
Scheme 153: Polycondensation of HO-LGOL and diols with dimethyl adipate.
Scheme 154: Self-condensation of Cyrene® and Claisen–Schmidt reactions.
Scheme 155: Synthesis of 5-amino-2-(hydroxymethyl)tetrahydropyran from Cyrene®.
Switchable pathways of multicomponent heterocyclizations of 5-amino-1,2,4-triazoles with salicylaldehydes and pyruvic acid
- Yana I. Sakhno,
- Oleksander V. Buravov,
- Kostyantyn Yu. Yurkov,
- Anastasia Yu. Andryushchenko,
- Svitlana V. Shishkina and
- Valentyn A. Chebanov
Beilstein J. Org. Chem. 2025, 21, 2030–2035, doi:10.3762/bjoc.21.158
- similar compounds based on 5-amino-1H-pyrazole-4-carbonitrile [22]. It should be noted that diazocines 4 were stable and did not undergo transformations when heated or irradiated with ultrasound. This may indicate that pyrimidine-7-carboxylic acids 5 and 6 are formed in parallel processes under kinetic
Graphical Abstract
Scheme 1: Diversity of heterocyclization products from reaction of aminoazoles with salicylaldehydes, and pyr...
Scheme 2: MCRs of 3-amino-5-methylthio-1,2,4-triazole (1a) and 3-amino-5-methoxy-1,2,4-triazole (1b) with sal...
Scheme 3: MCRs of 3-amino-5-methylthio-1,2,4-triazole (1a), salicylaldehydes 2a–c,f, and pyruvic acid (3) und...
Figure 1: Molecular structure of compound 4c according to X-ray diffraction data. Thermal ellipsoids are show...
Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics
- Leticia A. Gomes and
- Steven A. Lopez
Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156
- to experimentally measure the stereoselectivity of the reaction. In 1965, Crawford and co-workers experimentally found kinetic evidence for a 1,3-diradical from the thermal decomposition of 1 [56]. In 1963, Steel investigated the photolysis of diazabicyclo[2.1.1]hep-2-ene in solution, and the
Graphical Abstract
Scheme 1: Applications of bicyclo[1.1.0]butane (a) and bicyclo[2.1.0]pentane (b). Molecules with biological a...
Scheme 2: Diastereoselectivity in the direct photolysis of 2,3-diazabicyclo[2.2.1]hept-2-enes.
Scheme 3: Mechanism for the photodenitrogenation of DBH proposed in the literature.
Figure 1: CASSCF(8,9) active space of 1 with average electron occupancies. Orbitals were calculated at the SA...
Figure 2: Absorption spectra and geometric overlays corresponding to Wigner-sampled geometries of 1 (a), 3 (b...
Figure 3: Minimum energy path using XMS-CASPT2(8,9)/ANO-S-VDZP for 1 (a), 3 (b), and 5 (c). The dots on the g...
Figure 4: (a) The bond lengths we calculated are depicted. σCN bonds plotted against each other for 1 (b), 3 ...
Figure 5: (a) Geometrical parameters. Plots show trajectories for a 1 ps NAMD simulation with CASSCF (8,9)/AN...
Figure 6: (a) Geometrical parameters. H–C–C–C dihedral angles plotted against each other for S1-to-S0 hopping...
Figure 7: The minimum energy conical intersection geometries are shown for the partially inverted hopping poi...
Enantioselective desymmetrization strategy of prochiral 1,3-diols in natural product synthesis
- Lihua Wei,
- Rui Yang,
- Zhifeng Shi and
- Zhiqiang Ma
Beilstein J. Org. Chem. 2025, 21, 1932–1963, doi:10.3762/bjoc.21.151
- suppress potential intramolecular acyl migration. To further improve the optical purity of monoester 53, a Pseudomonas aeruginosa lipase-mediated kinetic resolution was performed with ethoxyvinyl butyrate 54, ultimately achieving monoester 53 with 97% ee in 60% yield and the diester 53a. With
- -worker described the asymmetric synthesis of (−)-rasfonin, harnessing an enantioselective enzymatic desymmetrization with lipase AK and an enzymatic oxidative kinetic resolution to install stereocenters [47]. The synthesis commenced with the preparation of fragment 100 from ethylene glycol (97) (Scheme
- functional group manipulations, alcohol 103 was subjected to enzymatic oxidative kinetic resolution with the bacterium Gluconobacter oxydans, producing alcohol 104 and acid 105. The alcohol 104 with the desired C9 stereocenter was then converted into fragment 106 in nine steps, while acid 105 was recycled to
Graphical Abstract
Scheme 1: General mechanism of a lipase-catalyzed esterification.
Scheme 2: Shishido’s synthesis of (−)-xanthorrhizol (4) and (+)-heliannuol D (8).
Scheme 3: Shishido’s synthesis of a) (−)-heliannuol A (15) and b) heliannuol G (20) and heliannuol H (21).
Scheme 4: Deska’s synthesis of hyperione A (30) and ent-hyperione B (31).
Scheme 5: Huang’s synthesis of (+)-brazilin (37).
Scheme 6: Shishido’s synthesis of (−)-heliannuol D (42) and (+)-heliannuol A (43).
Scheme 7: Chênevert’s synthesis of (S)-α-tocotrienol (49).
Scheme 8: Kita’s synthesis of monoester 53.
Scheme 9: Kita’s synthesis of fredericamycin A (60).
Scheme 10: Takabe’s synthesis of (E)-3,7-dimethyl-2-octene-1,8-diol (64).
Scheme 11: Takabe’s synthesis of (18S)-variabilin (70).
Scheme 12: Kawasaki’s synthesis of (S)-Rosaphen (74) and (R)-Rosaphen (75).
Scheme 13: Tokuyama’s synthesis of a) (−)-petrosin (84) and b) (+)-petrosin (86).
Scheme 14: Fukuyama’s synthesis of leustroducsin B (96).
Scheme 15: Nanda’s synthesis of a) fragment 100, b) fragment 106 and c) (−)-rasfonin (109).
Scheme 16: Davies’ synthesis of (+)-pilocarpine (115) and (+)-isopilocarpine (116).
Scheme 17: Ōmura’s synthesis of salinosporamide A (125).
Scheme 18: Kang’s synthesis of ʟ-cladinose (124) and its derivative.
Scheme 19: Kang’s preparation of fragment 139.
Scheme 20: Kang’s synthesis of azithromycin (149).
Scheme 21: Kang’s synthesis of (−)-dysiherbaine (156).
Scheme 22: Kang’s synthesis of (−)-kaitocephalin (166).
Scheme 23: Kang’s synthesis of laidlomycin (180).
Scheme 24: Snyder’s synthesis of arboridinine (190).
Scheme 25: Ma’s synthesis of (+)-alstrostine G (203).
Scheme 26: Trost’s synthesis of (−)-18-epi-peloruside A (215).
Scheme 27: Lindel’s synthesis of (–)-dihydroraputindole (223).
Scheme 28: Iwata’s synthesis of a) (−)-talaromycin B (232) and b) (+)-talaromycin A (235).
Scheme 29: Cook’s synthesis of a) (−)-vincamajinine (240) and b) (−)-11-methoxy-17-epivincamajine (245).
Scheme 30: Cook’s synthesis of (+)-dehydrovoachalotine (249) and voachalotine (250).
Scheme 31: Cook’s synthesis of a) (−)-12-methoxy-Nb-methylvoachalotine (257) and b) (+)-polyneuridine, macusin...
Scheme 32: Trauner’s synthesis of stephadiamine (273).
Scheme 33: Garg’s synthesis of (–)-ψ-akuammigine (285).
Scheme 34: Ding’s synthesis of (+)-18-benzoyldavisinol (293) and (+)-davisinol (294).
Chiral phosphoric acid-catalyzed asymmetric synthesis of helically chiral, planarly chiral and inherently chiral molecules
- Wei Liu and
- Xiaoyu Yang
Beilstein J. Org. Chem. 2025, 21, 1864–1889, doi:10.3762/bjoc.21.145
- without the CPA catalyst. Notably, indolohelicenoid 23e could effectively be converted into the fully aromatic indolohelicene 24e under DDQ-mediated oxidative conditions without compromising the enantiopurity of the compound. Kinetic resolution stands as one of the most practical and efficient strategies
- ]. While CPAs have been extensively utilized in kinetic resolution of centrally chiral [26][27][28] and axially chiral compounds [29], their application in the kinetic resolution of helically chiral compounds remains largely unexplored. In 2024, Liu and co-workers developed an effective method for
- catalytic kinetic resolution of racemic helical polycyclic phenols through an organocatalyzed enantioselective dearomative amination reaction [30]. The racemic polycyclic phenol derivatives 25, which exist as single diastereomers featuring both central chirality and helical chirality, were readily prepared
Graphical Abstract
Figure 1: General structure of CPAs and selected CPAs with various chiral scaffolds.
Figure 2: Representative elements of molecular chirality.
Scheme 1: CPA-catalyzed asymmetric synthesis of azahelicenes via Fischer indole synthesis.
Scheme 2: CPA-catalyzed asymmetric synthesis of azahelicenes via sequential Povarov reaction and oxidative ar...
Scheme 3: CPA-catalyzed asymmetric synthesis of azahelicenes via sequential Povarov reaction involving 3-viny...
Scheme 4: CPA-catalyzed asymmetric synthesis of heterohelicenes via sequential Povarov reaction involving 2-v...
Scheme 5: Diverse enantioselective synthesis of hetero[7]helicenes via a CPA-catalyzed double annulation stra...
Scheme 6: CPA-catalyzed asymmetric synthesis of indolohelicenoids through enantioselective cycloaddition and ...
Scheme 7: Kinetic resolution of helical polycyclic phenols via CPA-catalyzed enantioselective aminative dearo...
Scheme 8: Kinetic resolution of azahelicenes via CPA-catalyzed transfer hydrogenation.
Scheme 9: Asymmetric synthesis of planarly chiral macrocycles via CPA-catalyzed electrophilic aromatic aminat...
Scheme 10: Enantioselective synthesis of planarly chiral macrocycles via CPA-catalyzed macrocyclization.
Scheme 11: (Dynamic) kinetic resolution of planarly chiral paracyclophanes via CPA-catalyzed asymmetric reduct...
Scheme 12: Kinetic resolution of macrocyclic paracyclophanes through CPA/Bi-catalyzed asymmetric allylation.
Scheme 13: Enantioselective synthesis of planarly chiral macrocycles via CPA-catalyzed coupling of carboxylic ...
Scheme 14: Kinetic resolution of substituted amido[2.2]paracyclophanes via CPA-catalyzed asymmetric electrophi...
Scheme 15: Enantioselective synthesis of inherently chiral calix[4]arenes via sequential CPA-catalyzed Povarov...
Scheme 16: Asymmetric synthesis of inherently chiral calix[4]arenes via CPA-catalyzed aminative desymmetrizati...
Scheme 17: Asymmetric synthesis of chiral heterocalix[4]arenes via CPA-catalyzed intramolecular SNAr reaction.
Scheme 18: Enantioselective synthesis of inherently chiral DDDs via CPA-catalyzed cyclocondensation.
Scheme 19: Asymmetric synthesis of saddle-shaped inherently chiral 9,10-dihydrotribenzoazocines via CPA-cataly...
Scheme 20: Enantioselective synthesis of inherently chiral saddle-shaped dibenzo[b,f][1,5]diazocines via CPA-c...
Scheme 21: Enantioselective synthesis of inherent chiral 7-membered tribenzocycloheptene oximes via CPA-cataly...
Photoswitches beyond azobenzene: a beginner’s guide
- Michela Marcon,
- Christoph Haag and
- Burkhard König
Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143
- absence of light. Apart from some special cases where more competing mechanisms are operating [5], the thermal isomerisation typically is a first-order decay: Where I is the monitored signal at the time t, I0 the initial signal, and k the kinetic constant. Once k is known, the thermal half-life t1/2 can
Graphical Abstract
Figure 1: Energy diagram of a two-state photoswitch. Figure 1 was redrawn from [2].
Figure 2: Example of the absorption spectra of the isomers of a photoswitch with most efficient irradiation w...
Scheme 1: Photoswitch classes described in this review.
Figure 3: Azoheteroarenes.
Scheme 2: E–Z Isomerisation (top) and mechanisms of thermal Z–E isomerisation (bottom).
Scheme 3: Rotation mechanism favoured by the electron displacement in push–pull systems. Selected examples of...
Figure 4: A) T-shaped and twisted Z-isomers determine the thermal stability and the Z–E-PSS (selected example...
Figure 5: Effect of di-ortho-substitution on thermal half-life and PSS.
Figure 6: Selected thermal lifetimes of azoindoles in different solvents and concentrations. aConcentration o...
Figure 7: Aryliminopyrazoles: N-pyrazoles (top) and N-phenyl (bottom).
Scheme 4: Synthesis of symmetrical heteroarenes through oxidation (A), reduction (B), and the Bayer–Mills rea...
Scheme 5: Synthesis of diazonium salt (A); different strategies of azo-coupling: with a nucleophilic ring (B)...
Scheme 6: Synthesis of arylazothiazoles 25 (A) and heteroaryltriazoles 28 (B).
Scheme 7: Synthesis of heteroarylimines 31a,b [36-38].
Figure 8: Push–pull non-ionic azo dye developed by Velasco and co-workers [45].
Scheme 8: Azopyridine reported by Herges and co-workers [46].
Scheme 9: Photoinduced phase transitioning azobispyrazoles [47].
Figure 9: Diazocines.
Scheme 10: Isomers, conformers and enantiomers of diazocine.
Scheme 11: Partial overlap of the ππ* band with electron-donating substituents and effect on the PSS. Scheme 11 was ada...
Figure 10: Main properties of diazocines with different bridges. aMeasured in n-hexane [56]. bMeasured in THF. cMe...
Scheme 12: Synthesis of symmetric diazocines.
Scheme 13: Synthesis of asymmetric diazocines.
Scheme 14: Synthesis of O- and S-heterodiazocines.
Scheme 15: Synthesis of N-heterodiazocines.
Scheme 16: Puromycin diazocine photoswitch [60].
Figure 11: Indigoids.
Figure 12: The main representatives of the indigoid photoswitch class.
Scheme 17: Deactivation process that prevents Z-isomerisation of indigo.
Figure 13: Stable Z-indigo derivative synthesised by Wyman and Zenhäusern [67].
Figure 14: Selected examples of indigos with aliphatic and aromatic substituents [68]. Dashed box: proposed π–π in...
Scheme 18: Resonance structures of indigo and thioindigo involving the phenyl ring.
Scheme 19: Possible deactivation mechanism for 4,4'-dihydroxythioindigo [76].
Scheme 20: Effect of different heteroaryl rings on the stability and the photophysical properties of hemiindig...
Figure 15: Thermal half-lives of red-shifted hemithioindigos in toluene [79]. aMeasured in toluene-d8.
Scheme 21: Structures of pyrrole [81] and imidazole hemithioindigo [64].
Figure 16: Examples of fully substituted double bond hemithioindigo (left), oxidised hemithioindigos (centre),...
Scheme 22: Structure of iminothioindoxyl 72 (top) and acylated phenyliminoindolinone photoswitch 73 (bottom). ...
Scheme 23: (top) Transition states of iminothioindoxyl 72. The planar transition state is associated with a lo...
Scheme 24: Baeyer–Drewsen synthesis of indigo (top) and N-functionalisation strategies (bottom).
Scheme 25: Synthesis of hemiindigo.
Scheme 26: Synthesis of hemithioindigo and iminothioindoxyl.
Scheme 27: Synthesis of double-bond-substituted hemithioindigos.
Scheme 28: Synthesis of phenyliminoindolinone.
Scheme 29: Hemithioindigo molecular motor [85].
Figure 17: Arylhydrazones.
Scheme 30: Switching of arylhydrazones. Note: The definitions of stator and rotor are arbitrary.
Scheme 31: Photo- and acidochromism of pyridine-based phenylhydrazones.
Scheme 32: A) E–Z thermal inversion of a thermally stable push–pull hydrazone [109]. B) Rotation mechanism favoured...
Scheme 33: Effect of planarisation on the half-life.
Scheme 34: The longest thermally stable hydrazone switches reported so far (left). Modulation of thermal half-...
Figure 18: Dependency of t1/2 on concentration and hypothesised aggregation-induced isomerisation.
Figure 19: Structure–property relationship of acylhydrazones.
Scheme 35: Synthesis of arylhydrazones.
Scheme 36: Synthesis of acylhydrazones.
Scheme 37: Photoswitchable fluorophore by Aprahamian et al. [115].
Scheme 38: The four-state photoswitch synthesised by the Cigáň group [116].
Figure 20: Diarylethenes.
Scheme 39: Isomerisation and oxidation pathway of E-stilbene to phenanthrene.
Scheme 40: Strategies adapted to avoid E–Z isomerisation and oxidation.
Scheme 41: Molecular orbitals and mechanism of electrocyclisation for a 6π system.
Figure 21: Aromatic stabilisation energy correlated with the thermal stability of the diarylethenes [127,129].
Figure 22: Half-lives of diarylethenes with increasing electron-withdrawing groups [128,129].
Scheme 42: Photochemical degradation pathway promoted by electron-donating groups [130].
Figure 23: The diarylethenes studied by Hanazawa et al. [134]. Increased rigidity leads to bathochromic shift.
Scheme 43: The dithienylethene synthesised by Nakatani's group [135].
Scheme 44: Synthesis of perfluoroalkylated diarylethenes.
Scheme 45: Synthesis of 139 and 142 via McMurry coupling.
Scheme 46: Synthesis of symmetrical derivatives 145 via Suzuki–Miyaura coupling.
Scheme 47: Synthesis of acyclic 148, malonic anhydride 149, and maleimide derivatives 154.
Figure 24: Gramicidin S (top left) and two of the modified diarylethene derivatives: first generation (bottom ...
Scheme 48: Pyridoxal 5'-phosphate and its reaction with an amino acid (top). The analogous dithienylethene der...
Figure 25: Fulgides.
Scheme 49: The three isomers of fulgides.
Scheme 50: Thermal and photochemical side products of unsubstituted fulgide [150].
Figure 26: Maximum absorption λc of the closed isomer compared with the nature of the aromatic ring and the su...
Scheme 51: Possible rearrangement of the excited state of 5-dimethylaminoindolylfulgide [153].
Figure 27: Quantum yields of ring closure (ΦE→C) and E–Z isomerisation (ΦE→Z) correlated with the increasing s...
Scheme 52: Active (Eα) and inactive (Eβ) conformers (left) and the bicyclic sterically blocked fulgide 169 (ri...
Scheme 53: Quantum yield of ring-opening (ΦC→E) and E–Z isomerisation (ΦE→Z) for different substitution patter...
Scheme 54: Stobbe condensation pathway for the synthesis of fulgides 179, fulgimides 181 and fulgenates 178.
Scheme 55: Alternative synthesis of fulgides through Pd-catalysed carbonylation.
Scheme 56: Optimised synthesis of fulgimides [166].
Scheme 57: Photoswitchable FRET with a fulgimide photoswitch [167].
Scheme 58: Three-state fulgimide strategy by Slanina's group.
Figure 28: Spiropyrans.
Scheme 59: Photochemical (left) and thermal (right) ring-opening mechanisms for an exemplary spiropyran with a...
Figure 29: Eight possible isomers of the open merocyanine according to the E/Z configurations of the bonds hig...
Scheme 60: pH-Controlled photoisomerisation between the closed spiropyran 191-SP and the open E-merocyanine 19...
Scheme 61: Behaviour of spiropyran in water buffer according to Andréasson and co-workers [180]. 192-SP in an aqueo...
Scheme 62: (left box) Proposed mechanism of basic hydrolysis of MC [184]. (right box) Introduction of electron-dona...
Scheme 63: Photochemical interconversion of naphthopyran 194 (top) and spirooxazine 195 (bottom) photoswitches...
Scheme 64: Synthesis of spiropyrans and spirooxazines 198 and the dicondensation by-product 199.
Scheme 65: Alternative synthesis of spiropyrans and spirooxazines with indolenylium salt 200.
Scheme 66: Synthesis of 4’-substituted spiropyrans 203 by condensation of an acylated methylene indoline 201 w...
Scheme 67: Synthesis of spironaphthopyrans 210 by acid-catalysed condensation of naphthols and diarylpropargyl...
Scheme 68: Photoswitchable surface wettability [194].
Figure 30: Some guiding principles for the choice of the most suitable photoswitch. Note that this guide is ve...
Research progress on calixarene/pillararene-based controlled drug release systems
- Liu-Huan Yi,
- Jian Qin,
- Si-Ran Lu,
- Liu-Pan Yang,
- Li-Li Wang and
- Huan Yao
Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139
- processes. For example, supramolecular self-assembly technology enhances the targeting of chemotherapeutic drugs to tumor tissues, reducing systemic adverse reactions. (3) Macrocyclic aromatic supramolecular nano-valves have a pseudo-rotaxane structure with host–guest coordination and the kinetic properties
Graphical Abstract
Figure 1: Schematic diagram of drug-controlled release mechanisms based on aromatic macrocycles.
Figure 2: Chemical structure of a) calix[n]arene (m = 1,3,5), and b) pillar[n]arene (m = 1,2,3).
Figure 3: Changes in pH conditions cause the release of drugs from CA8 host–guest complexes [101]. Figure 3 was adapted wi...
Figure 4: The illustration of the pH-mediated 1:1 complex formation between the host and guest molecules in a...
Figure 5: Illustration of the pH-responsive self-assembly of mannose-modified CA4 into micelles and the subse...
Figure 6: Illustration of the assembly of supramolecular prodrug nanoparticles from WP6 and DOX-derived prodr...
Figure 7: Illustration of the formation of supramolecular vesicles and their pH-dependent drug release [93]. Figure 7 was...
Figure 8: Schematic illustration of the application of the multifunctional nanoplatform CyCA@POPD in combined...
Figure 9: Illustration of the photolysis of an amphiphilic assembly via CA-induced aggregation [114]. Figure 9 was reprint...
Figure 10: Schematic illustration of drug release controlled by the photo-responsive macroscopic switch based ...
Figure 11: Schematic illustration of the formation process of Azo-SMX and its photoisomerization reaction unde...
Figure 12: Schematic illustration of the enzyme-responsive behavior of supramolecular polymers [95]. Figure 12 was used wit...
Figure 13: Schematic illustration of the amphiphilic assembly of SC4A and its enzyme-responsive applications [119]. ...
Figure 14: Stimuli-responsive nanovalves based on MSNs and choline-SC4A[2]pseudorotaxanes, MSN-C1 with ester-l...
Figure 15: A schematic diagram showing the construction of a supramolecular system by host–guest interaction b...
Figure 16: A schematic diagram showing the formation of the host–guest complex DOX@Biotin-SAC4A by biotin modi...
Figure 17: A schematic diagram showing the self-assembly of CA4 into a hypoxia-responsive peptide hydrogel, wh...
Figure 18: Schematic illustration of the formation process of Lip@GluAC4A and the release of Lip under hypoxic...
Figure 19: Schematic illustration of the construction of a supramolecular vesicle based on the host–guest comp...
Figure 20: Schematic illustration of WP6 self-assembly at pH > 7, and the stimulus-responsive drug release beh...
Figure 21: Schematic illustration of the formation of supramolecular vesicles based on the WP5⊃G super-amphiph...
Figure 22: Schematic illustrations of the host–guest recognition of QAP5⊃SXD, the formation of the nanoparticl...
Figure 23: Schematic illustration of the activation of T-SRNs by acid, alkali, or Zn2+ stimuli to regulate the...
Figure 24: Illustration of the triggered release of BH from CP[5]A@MSNs-Q NPs in response to a drop in pH or a...
Figure 25: Illustration of the supramolecular amphiphiles TPENCn@1 (n = 6 and 12) self-assembling with disulfi...
Approaches to stereoselective 1,1'-glycosylation
- Daniele Zucchetta and
- Alla Zamyatina
Beilstein J. Org. Chem. 2025, 21, 1700–1718, doi:10.3762/bjoc.21.133
- '-neotrehalosamines 7 and 9, respectively (Scheme 1) [38]. The stereochemical outcome was found to be independent of the initial anomeric configuration of the N-phthalimido-protected lactol acceptor, which was explained by kinetic control and a rapid anomerization in favor of the β-anomer [50]. The applicability of
Graphical Abstract
Scheme 1: Application of chloride-, bromide-, and trichloroacetimidate donors in 1,1'-coupling reactions towa...
Scheme 2: Application of trichloroacetimidates as donors in 1,1'-β,α coupling reactions and the use of 1,2-or...
Scheme 3: The β-anomeric configuration in the lactol acceptors can be trapped and fixed within the five-membe...
Scheme 4: Diarylborinic acid-promoted β,α-1,1' glycosylation.
Scheme 5: The anomeric configuration in the lactol acceptor can be trapped in the form of a TMS-glycoside.
Scheme 6: The anomeric configuration in the lactol acceptor can be trapped in form of a 1-O-TMS-glycoside tha...
Scheme 7: Influence of remote protecting groups on the stereoselectivity and efficiency of 1,1'-β,α bond form...
Scheme 8: Synthesis of non-symmetrically fully orthogonally protected β,α-1,1' diglucosamines.
Scheme 9: Synthesis of non-symmetric β,β-1,1'-linked disaccharides.
Scheme 10: Synthesis of non-symmetric, fully orthogonally protected β,β-1,1'-diglucosamines.
Scheme 11: Synthesis of α,α-1,1'-disaccharides.
Scheme 12: Synthesis of α,α-1,1'-thiodisacchrides.
Scheme 13: Synthesis of partially desymmetrized α,α-1,1'-linked disaccharides.
Scheme 14: Synthesis of non-symmetric orthogonally protected α,α-1,1'-linked disaccharides involving an aminos...
Continuous-flow-enabled intensification in nitration processes: a review of technological developments and practical applications over the past decade
- Feng Zhou,
- Chuansong Duanmu,
- Yanxing Li,
- Jin Li,
- Haiqing Xu,
- Pan Wang and
- Kai Zhu
Beilstein J. Org. Chem. 2025, 21, 1678–1699, doi:10.3762/bjoc.21.132
- classifications necessitate tailored nitrating reagent selections, giving rise to fundamentally distinct mechanistic pathways. This reactivity is exemplified by the comparative kinetic profiles: N-nitration of amines and O-nitration of alcohols – facilitated by accessible lone electron pairs – exhibit markedly
- higher kinetic feasibility than aliphatic C-nitration in saturated carbon frameworks [3]. Following determination of substrate–nitrating agent combinations, reactor system specification emerges as the critical engineering decision. Nitration reactor selection – encompassing batch, semi-batch, continuous
- , throughput, and side reactions. The reaction temperature (usually 0–60 °C) governs kinetic rates and selectivity, where lower temperatures suppress polynitration reactions while higher temperatures demand enhanced heat dissipation. The molar ratio of HNO3/substrate (usually 1.0–3.0) directly regulates the
Graphical Abstract
Figure 1: Three key dimensions of a complete nitration process.
Figure 2: A typical continuous-flow nitration reaction system.
Figure 3: Corrosion characteristics of common wetted materials used in continuous-flow nitration system. Note...
Figure 4: Analysis of the literature on continuous-flow nitration reaction over the past decade.
Scheme 1: Model reaction for the homogeneous nitration by nitric acid/mixed acid.
Figure 5: Safety assessment criteria for nitration reactions. Notes: apressure-independent; bno hazards arisi...
Figure 6: Guide for the investigation of continuous-flow nitration processes.
Influence of the cation in hypophosphite-mediated catalyst-free reductive amination
- Natalia Lebedeva,
- Fedor Kliuev,
- Olesya Zvereva,
- Klim Biriukov,
- Evgeniya Podyacheva,
- Maria Godovikova,
- Oleg I. Afanasyev and
- Denis Chusov
Beilstein J. Org. Chem. 2025, 21, 1661–1670, doi:10.3762/bjoc.21.130
- the target amine (Scheme 4c). The experiments with H3PO2 and D3PO2 resulted in the same yield of the amine obtained from enamine under the same reaction conditions. Thus, the kinetic isotope effect (KIE) was not observed in reduction of enamine. Although the experiments with D3PO2 did not allow us to
Graphical Abstract
Scheme 1: Rationale of the current study: a) Our previous work [20]; b) this work.
Scheme 2: Comparison of KH2PO2 and NaH2PO2 under the optimal conditions.
Figure 1: Substrate scope. Reaction conditions: carbonyl compound (1.45 mmol, 1 equiv), amine (1.81 mmol, 1.2...
Scheme 3: Control experiments.
Scheme 4: Experiments with D3PO2.
Scheme 5: Principal steps of the mechanism of the reductive amination with K2CO3/H3PO2 reducing system.
Figure 2: Reaction profile and DFT energies of intermediates and transition states. M062X functional with the...
Catalytic asymmetric reactions of isocyanides for constructing non-central chirality
- Jia-Yu Liao
Beilstein J. Org. Chem. 2025, 21, 1648–1660, doi:10.3762/bjoc.21.129
- unsymmetrical diisocyanide was used, the initial isocyanide insertion was found to be non-regioselective, delivering a 1:1 mixture of regioisomers (17c and 17c’). Intriguingly, 17a could act as a chiral acylating reagent, applying in the kinetic resolution of racemic primary amines rac-18. Additionally, after
- reaction between alkene 43 and 2,2′-dienone 44. The corresponding spirooxindole 45 was obtained in >19:1 dr, 63% yield, and 89% ee. Dynamic kinetic resolution of configurationally labile bridged biaryls The catalytic asymmetric dynamic kinetic resolution (DKR) of configurationally labile bridged biaryls
- Groebke–Blackburn–Bienaymé reaction. Construction of axially chiral 3-arylpyrroles via de novo pyrrole formation. Synthesis of atropoisomeric 3-arylpyrroles via central-to-axial chirality transfer. Dynamic kinetic resolution of bridged biaryls with α-acidic isocyanides. Desymmetrization of prochiral
Graphical Abstract
Figure 1: a) Common types of chirality. b) Representative functional molecules bearing non-central chirality.
Scheme 1: Construction of planar chirality.
Scheme 2: Construction of axial chirality.
Scheme 3: Construction of inherent chirality.
Scheme 4: Construction of helical chirality.
Scheme 5: CPA-catalyzed enantioselective Groebke–Blackburn–Bienaymé reaction.
Scheme 6: Construction of axially chiral 3-arylpyrroles via de novo pyrrole formation.
Scheme 7: Synthesis of atropoisomeric 3-arylpyrroles via central-to-axial chirality transfer.
Scheme 8: Dynamic kinetic resolution of bridged biaryls with α-acidic isocyanides.
Scheme 9: Desymmetrization of prochiral compounds with α-acidic isocyanides.
