- PERIOD
- Last 30 days
- per year
- whole period
A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis
- Magnus Rueping and
- Boris J. Nachtsheim
Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6
Graphical Abstract
Scheme 1: AlCl3-mediated reaction between amyl chloride and benzene as developed by Friedel and Crafts.
Figure 1: Most often used metal salts for catalytic FC alkylations and hydroarylations of arenes.
Figure 2: 1,1-diarylalkanes with biological activity.
Scheme 2: Alkylating reagents and side products produced.
Scheme 3: Initially reported TeCl4-mediated FC alkylation of 1-penylethanol with toluene.
Scheme 4: Sc(OTf)3-catalyzed FC benzylation of arenes.
Scheme 5: Reductive FC alkylation of arenes with arenecarbaldehydes.
Scheme 6: Iron(III)-catalyzed FC benzylation of arenes and heteroarenes.
Scheme 7: A gold(III)-catalyzed route to beclobrate.
Scheme 8: Catalytic FC-type alkylations of 1,3-dicarbonyl compounds.
Scheme 9: Iron(III)-catalyzed synthesis of phenprocoumon.
Scheme 10: Bi(OTf)3-catalyzed FC alkylation of benzyl alcohols developed by Rueping et al.
Scheme 11: (A) Bi(OTf)3-catalyzed intramolecular FC alkylation as an efficient route to substituted fulvenes. ...
Scheme 12: FC-type glycosylation of 1,2-dimethylindole and trimethoxybenzene.
Scheme 13: FC alkylation with highly reactive ferrocenyl- and benzyl alcohols. The reaction proceeds even with...
Scheme 14: Reductive FC alkylation of arenes with benzaldehyde and acetophenone catalyzed by the Ir-carbene co...
Scheme 15: Formal synthesis of 1,1-diarylalkanes from benzyl alcohols and styrenes.
Scheme 16: (A) Mo-catalyzed hydroarylation of styrenes and cyclohexenes. (B) Hydroalkylation–cyclization casca...
Scheme 17: Bi(III)-catalyzed hydroarylation of styrenes with arenes and heteroarenes.
Scheme 18: BiCl3-catalyzed ene/FC alkylation reaction cascade – A fast access to highly arylated dihydroindene...
Scheme 19: Au(I)/Ag(I)-catalyzed hydroarylation of indoles with styrenes, aliphatic and cyclic alkenes.
Scheme 20: First transition-metal-catalyzed ortho-hydroarylation developed by Beller et al.
Scheme 21: (A) Ti(IV)-mediated rearrangement of an N-benzylated aniline to the corresponding ortho-alkylated a...
Scheme 22: Dibenzylation of aniline gives potentially useful amine-based ligands in a one-step procedure.
Scheme 23: FC-type alkylations with allyl alcohols as alkylating reagents – linear vs. branched product format...
Scheme 24: (A) First catalytic FC allylation and cinnamylation using allyl alcohols and its derivatives. (B) E...
Scheme 25: FC allylation/cyclization reaction yielding substituted chromanes.
Scheme 26: Synthesis of (all-rac)-α-tocopherol utilizing Lewis- and strong Brønsted-acids.
Scheme 27: Au(III)-catalyzed cinnamylation of arenes.
Scheme 28: “Exhaustive” allylation of benzene-1,3,5-triol.
Scheme 29: Palladium-catalyzed allylation of indole.
Scheme 30: Pd-catalyzed synthesis of pyrroloindoles from L-tryptophane.
Scheme 31: Ru(IV)-catalyzed allylation of indole and pyrroles with unique regioselectivity.
Scheme 32: Silver(I)-catalyzed intramolecular FC-type allylation of arenes and heteroarenes.
Scheme 33: FC-type alkylations of arenes using propargyl alcohols.
Scheme 34: (A) Propargylation of arenes with stoichiometric amounts of the Ru-allenylidene complex 86. (B) Fir...
Scheme 35: Diruthenium-catalyzed formation of chromenes and 1H-naphtho[2,1-b]pyrans.
Scheme 36: Rhenium(V)-catalyzed FC propargylations as a first step in the total synthesis of podophyllotoxin, ...
Scheme 37: Scandium-catalyzed arylation of 3-sulfanyl- and 3-selanylpropargyl alcohols.
Scheme 38: Synthesis of 1,3-diarylpropynes via direct coupling of propargyl trichloracetimidates and arenes.
Scheme 39: Diastereoselective substitutions of benzyl alcohols.
Scheme 40: (A) First diastereoselective FC alkylations developed by Bach et al. (B) anti-Selective FC alkylati...
Scheme 41: Diastereoselective AuCl3-catalyzed FC alkylation.
Scheme 42: Bi(OTf)3-catalyzed alkylation of α-chiral benzyl acetates with silyl enol ethers.
Scheme 43: Bi(OTf)3-catalyzed diastereoselective substitution of propargyl acetates.
Scheme 44: Nucelophilic substitution of enantioenriched ferrocenyl alcohols.
Scheme 45: First catalytic enantioselective propargylation of arenes.
Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes
- Bartłomiej Pigulski
Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99
Graphical Abstract
Figure 1: a) Stone–Wales (red) and azulene (blue) defects in graphene; b) azulene and its selected resonance ...
Figure 2: Examples of azulene-embedded 2D allotropic forms of carbon: a) phagraphene and b) TPH-graphene.
Scheme 1: Synthesis of non-alternant isomers of pyrene (2 and 6) using dehydrogenation.
Scheme 2: Synthesis of non-alternant isomer 9 of benzo[a]pyrene and 14 of benzo[a]perylene using dehydrogenat...
Scheme 3: Synthesis of azulene-embedded isomers of benzo[a]pyrene (18 and 22) inspired by Ziegler–Hafner azul...
Figure 3: General strategies leading to azulene-embedded nanographenes: a) construction of azulene moiety in ...
Scheme 4: Synthesis of biradical PAHs possessing significant biradical character using oxidation of partially...
Scheme 5: Synthesis of dicyclohepta[ijkl,uvwx]rubicene (29) and its further modifications.
Scheme 6: Synthesis of warped PAHs with one embedded azulene subunit using Scholl-type oxidation.
Scheme 7: Synthesis of warped PAHs with two embedded azulene subunits using Scholl oxidation.
Scheme 8: Synthesis of azulene-embedded PAHs using [3 + 2] annulation accompanied by ring expansion.
Scheme 9: Synthesis of azulene-embedded isomers of linear acenes using [3 + 2] annulation accompanied by ring...
Scheme 10: Synthesis of azulene-embedded PAHs using intramolecular C–H arylation.
Scheme 11: Synthesis of azulene-embedded isomers of acenes using intramolecular C–H arylation.
Scheme 12: Synthesis of azulene-embedded PAHs using intramolecular condensations.
Scheme 13: Synthesis of azulene-embedded PAH 89 using palladium-catalysed [5 + 2] annulation.
Scheme 14: Synthesis of azulene-embedded PAHs using oxidation of substituents around the azulene core.
Scheme 15: Synthesis of azulene-embedded PAHs using the oxidation of reactive positions 1 and 3 of azulene sub...
Scheme 16: Synthesis of azulene-embedded PAHs using intramolecular C–H arylation.
Scheme 17: Synthesis of an azulene-embedded isomer of terylenebisimide using tandem Suzuki coupling and C–H ar...
Scheme 18: Synthesis of azulene embedded PAHs using a bismuth-catalyzed cyclization of alkenes.
Scheme 19: Synthesis of azulene-embedded nanographenes using intramolecular cyclization of alkynes.
Scheme 20: Synthesis of azulene-embedded graphene nanoribbons and azulene-embedded helicenes using annulation ...
Scheme 21: Synthesis of azulene-fused acenes.
Scheme 22: Synthesis of non-alternant isomer of perylene 172 using Yamamoto-type homocoupling.
Scheme 23: Synthesis of N- and BN-nanographenes with embedded azulene unit(s).
Scheme 24: On-surface synthesis of azulene-embedded nanographenes from benzenoid precursors via dehydrogenatio...
Scheme 25: On-surface synthesis of azulene-embedded nanographenes from benzenoid precursors.
Scheme 26: On-surface synthesis of azulene-embedded nanoribbons.
Recent advances in synthetic approaches for bioactive cinnamic acid derivatives
- Betty A. Kustiana,
- Galuh Widiyarti and
- Teni Ernawati
Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85
Graphical Abstract
Figure 1: Biologically active cinnamic acid derivatives.
Scheme 1: General synthetic strategies for cinnamic acid derivatizations.
Scheme 2: Cinnamic acid coupling via isobutyl anhydride formation.
Scheme 3: Amidation reaction via O/N-pivaloyl activation.
Scheme 4: Cinnamic acid amidation using TCCA/PPh3 reagent.
Scheme 5: Cinnamic acid amidation using triazine-based reagents.
Scheme 6: Cinnamic acid amidation using continuous flow mechanochemistry.
Scheme 7: Cinnamic acid amidation using COMU as coupling reagent.
Scheme 8: Cinnamic acid amidation using allenone coupling reagent.
Scheme 9: Cinnamic acid amidation using 4-acetamidophenyl triflimide as reagent.
Scheme 10: Cinnamic acid amidation using methyltrimethoxysilane (MTM).
Scheme 11: Cinnamic acid amidation utilizing amine–borane reagent.
Scheme 12: Cinnamic acid amidation using TCCA/PPh3 reagent.
Scheme 13: Cinnamic acid amidation using PPh3/I2 reagent.
Scheme 14: Cinnamic acid amidation using PCl3 reagent.
Scheme 15: Cinnamic acid amidation utilizing pentafluoropyridine (PFP) as reagent.
Scheme 16: Cinnamic acid amidation using hypervalent iodine(III).
Scheme 17: Mechanochemical amidation using 1,1,2,2-tetrafluoroethyl-N,N-dimethylamine (TFEDMA) reagent.
Scheme 18: Methyl ester preparation using tris(2,4,6-trimethoxyphenyl)phosphine (TMPP).
Scheme 19: N-Trifluoromethyl amide preparation using isothiocyanate and AgF.
Scheme 20: POCl3-mediated amide coupling of carboxylic acid and DMF.
Scheme 21: O-Alkylation of cinnamic acid using alkylating agents.
Scheme 22: Glycoside preparation via Mitsunobu reaction.
Scheme 23: O/N-Acylation via rearrangement reactions.
Scheme 24: Amidation reactions using sulfur-based alkylating agents.
Scheme 25: Amidation reaction catalyzed by Pd0 via C–N cleavage.
Scheme 26: Amidation reaction catalyzed by CuCl/PPh3.
Scheme 27: Cu(II) triflate-catalyzed N-difluoroethylimide synthesis.
Scheme 28: Cu/Selectfluor-catalyzed transamidation reaction.
Scheme 29: CuO–CaCO3-catalyzed amidation reaction.
Scheme 30: Ni-catalyzed reductive amidation.
Scheme 31: Lewis acidic transition-metal-catalyzed O/N-acylations.
Scheme 32: Visible-light-promoted amidation of cinnamic acid.
Scheme 33: Sunlight/LED-promoted amidation of cinnamic acid.
Scheme 34: Organophotocatalyst-promoted N–O cleavage of Weinreb amides to synthesize primary amides.
Scheme 35: Cinnamamide synthesis through [Ir] photocatalyst-promoted C–N-bond cleavage of tertiary amines.
Scheme 36: Blue LED-promoted FeCl3-catalyzed reductive transamidation.
Scheme 37: FPyr/TCT-catalyzed amidation of cinnamic acid derivative 121.
Scheme 38: Cs2CO3/DMAP-mediated esterification.
Scheme 39: HBTM organocatalyzed atroposelective N-acylation.
Scheme 40: BH3-catalyzed N-acylation reactions.
Scheme 41: Borane-catalyzed N-acylation reactions.
Scheme 42: Catalytic N-acylation reactions via H/F bonding activation.
Scheme 43: Brønsted base-catalyzed synthesis of cinnamic acid esters.
Scheme 44: DABCO/Fe3O4-catalyzed N-methyl amidation of cinnamic acid 122.
Scheme 45: Catalytic oxidation reactions of acylating agents.
Scheme 46: Preparation of cinnamamide-substituted benzocyclooctene using I(I)/I(III) catalysis.
Scheme 47: Pd-colloids-catalyzed oxidative esterification of cinnamyl alcohol.
Scheme 48: Graphene-supported Pd/Au alloy-catalyzed oxidative esterification via hemiacetal intermediate.
Scheme 49: Au-supported on A) carbon nanotubes (CNT) and B) on porous boron nitride (pBN) as catalyst for the ...
Scheme 50: Cr-based catalyzed oxidative esterification of cinnamyl alcohols with H2O2 as the oxidant.
Scheme 51: Co-based catalysts used for oxidative esterification of cinnamyl alcohol.
Scheme 52: Iron (A) and copper (B)-catalyzed oxidative esterification of cinnamaldehyde.
Scheme 53: NiHPMA-catalyzed oxidative esterification of cinnamaldehyde.
Scheme 54: Synthesis of cinammic acid esters through NHC-catalyzed oxidative esterification via intermolecular...
Scheme 55: Redox-active NHC-catalyzed esterification via intramolecular oxidation.
Scheme 56: Electrochemical conversion of cinnamaldehyde to methyl cinnamate.
Scheme 57: Bu4NI/TBHP-catalyzed synthesis of bisamides from cinnamalaldehyde N-tosylhydrazone.
Scheme 58: Zn/NC-950-catalyzed oxidative esterification of ketone 182.
Scheme 59: Ru-catalyzed oxidative carboxylation of terminal alkenes.
Scheme 60: Direct carboxylation of alkenes using CO2.
Scheme 61: Carboxylation of alkenylboronic acid/ester.
Scheme 62: Carboxylation of gem-difluoroalkenes with CO2.
Scheme 63: Photoredox-catalyzed carboxylation of difluoroalkenes.
Scheme 64: Ru-catalyzed carboxylation of alkenyl halide.
Scheme 65: Carboxylation of alkenyl halides under flow conditions.
Scheme 66: Cinnamic acid ester syntheses through carboxylation of alkenyl sulfides/sulfones.
Scheme 67: Cinnamic acid derivatives synthesis through a Ag-catalyzed decarboxylative cross-coupling proceedin...
Scheme 68: Pd-catalyzed alkyne hydrocarbonylation.
Scheme 69: Fe-catalyzed alkyne hydrocarbonylation.
Scheme 70: Alkyne hydrocarboxylation using CO2.
Scheme 71: Alkyne hydrocarboxylation using HCO2H as CO surrogate.
Scheme 72: Co/AlMe3-catalyzed alkyne hydrocarboxylation using DMF.
Scheme 73: Au-catalyzed oxidation of Au–allenylidenes.
Scheme 74: Pd-catalyzed C–C-bond activation of cyclopropenones to synthesize unsaturated esters and amides.
Scheme 75: Ag-catalyzed C–C-bond activation of diphenylcyclopropenone.
Scheme 76: Cu-catalyzed C–C bond activation of diphenylcyclopropenone.
Scheme 77: PPh3-catalyzed C–C-bond activation of diphenylcyclopropenone.
Scheme 78: Catalyst-free C–C-bond activation of diphenylcyclopropenone.
Scheme 79: Cu-catalyzed dioxolane cleavage.
Scheme 80: Multicomponent coupling reactions.
Scheme 81: Pd-catalyzed partial hydrogenation of electrophilic alkynes.
Scheme 82: Nickel and cobalt as earth-abundant transition metals used as catalysts for the partial hydrogenati...
Scheme 83: Metal-free-catalyzed partial hydrogenation of conjugated alkynes.
Scheme 84: Horner–Wadsworth–Emmons reaction between triethyl 2-fluoro-2-phosphonoacetate and aldehydes with ei...
Scheme 85: Preparation of E/Z-cinnamates using thiouronium ylides.
Scheme 86: Transition-metal-catalyzed ylide reactions.
Scheme 87: Redox-driven ylide reactions.
Scheme 88: Noble transition-metal-catalyzed olefination via carbenoid species.
Scheme 89: TrBF4-catalyzed olefination via carbene species.
Scheme 90: Grubbs catalyst (cat 7)/photocatalyst-mediated metathesis reactions.
Scheme 91: Elemental I2-catalyzed carbonyl-olefin metathesis.
Scheme 92: Cu-photocatalyzed E-to-Z isomerization of cinnamic acid derivatives.
Scheme 93: Ni-catalyzed E-to-Z isomerization.
Scheme 94: Dehydration of β-hydroxy esters via an E1cB mechanism to access (E)-cinnamic acid esters.
Scheme 95: Domino ring-opening reaction induced by a base.
Scheme 96: Dehydroamination of α-aminoester derivatives.
Scheme 97: Accessing methyl cinnamate (44) via metal-free deamination or decarboxylation.
Scheme 98: The core–shell magnetic nanosupport-catalyzed condensation reaction.
Scheme 99: Accessing cinnamic acid derivatives from acetic acid esters/amides through α-olefination.
Scheme 100: Accessing cinnamic acid derivatives via acceptorless α,β-dehydrogenation.
Scheme 101: Cu-catalyzed formal [3 + 2] cycloaddition.
Scheme 102: Pd-catalyzed C–C bond formation via 1,4-Pd-shift.
Scheme 103: NHC-catalyzed Rauhut–Currier reactions.
Scheme 104: Heck-type reaction for Cα arylation.
Scheme 105: Cu-catalyzed trifluoromethylation of cinnamamide.
Scheme 106: Ru-catalyzed alkenylation of arenes using directing groups.
Scheme 107: Earth-abundant transition-metal-catalyzed hydroarylation of α,β-alkynyl ester 374.
Scheme 108: Precious transition-metal-catalyzed β-arylation of cinnamic acid amide/ester.
Scheme 109: Pd-catalyzed β-amination of cinnamamide.
Scheme 110: S8-mediated β-amination of methyl cinnamate (44).
Scheme 111: Pd-catalyzed cross-coupling reaction of alkynyl esters with phenylsilanes.
Scheme 112: Pd-catalyzed β-cyanation of alkynyl amide/ester.
Scheme 113: Au-catalyzed β-amination of alkynyl ester 374.
Scheme 114: Metal-free-catalyzed Cβ-functionalizations of alkynyl esters.
Scheme 115: Heck-type reactions.
Scheme 116: Mizoroki–Heck coupling reactions using unconventional functionalized arenes.
Scheme 117: Functional group-directed Mizoroki–Heck coupling reactions.
Scheme 118: Pd nanoparticles-catalyzed Mizoroki–Heck coupling reactions.
Scheme 119: Catellani-type reactions to access methyl cinnamate with multifunctionalized arene.
Scheme 120: Multicomponent coupling reactions.
Scheme 121: Single atom Pt-catalyzed Heck coupling reaction.
Scheme 122: Earth-abundant transition metal-catalyzed Heck coupling reactions.
Scheme 123: Polymer-coated earth-abundant transition metals-catalyzed Heck coupling reactions.
Scheme 124: Earth-abundant transition-metal-based nanoparticles as catalysts for Heck coupling reactions.
Scheme 125: CN- and Si-based directing groups to access o-selective cinnamic acid derivatives.
Scheme 126: Amide-based directing group to access o-selective cinnamic acid derivatives.
Scheme 127: Carbonyl-based directing group to access o-selective cinnamic acid derivatives.
Scheme 128: Stereoselective preparation of atropisomers via o-selective C(sp2)–H functionalization.
Scheme 129: meta-Selective C(sp2)–H functionalization using directing group-tethered arenes.
Scheme 130: para-Selective C(sp2)–H functionalization using directing group-tethered arenes.
Scheme 131: Non-directed C(sp2)–H functionalization via electrooxidative Fujiwara–Moritani reaction.
Scheme 132: Interconversion of functional groups attached to cinnamic acid.
Scheme 133: meta-Selective C(sp2)–H functionalization of cinnamate ester.
Scheme 134: C(sp2)–F arylation using Grignard reagents.
Scheme 135: Truce–Smiles rearrangement of N-aryl metacrylamides.
Scheme 136: Phosphine-catalyzed cyclization of γ-vinyl allenoate with enamino esters.
Synthetic approach to borrelidin fragments: focus on key intermediates
- Yudhi Dwi Kurniawan,
- Zetryana Puteri Tachrim,
- Teni Ernawati,
- Faris Hermawan,
- Ima Nurasiyah and
- Muhammad Alfin Sulmantara
Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91
Graphical Abstract
Figure 1: Chemical structure of borrelidin (1).
Scheme 1: Synthetic strategy for Morken’s C2–C12 intermediate 20 as reported by Uguen et al. [41].
Scheme 2: Preparation of monoacetates 37 and ent-38 by Uguen et al. [41].
Scheme 3: Preparation of sulfones 27 and ent-27 by Uguen et al. [41].
Scheme 4: Attempts to couple sulfones 27 and ent-27 with epoxides 23a–c reported by Uguen et al. [41].
Scheme 5: Modified synthetic plan for Morken’s C2–C12 intermediate by Uguen [41].
Scheme 6: Revised synthetic strategy for Morken’s C2–C12 intermediate 20 by Uguen [41].
Scheme 7: Iterative synthesis of polydeoxypropionates developed by Zhou et al. [40].
Scheme 8: Application of iterative synthesis of polydeoxypropionate to construct the C3–C11 fragment 60 of bo...
Scheme 9: Retrosynthetic analysis of borrelidin by Yadav et al. [39].
Scheme 10: Two-carbon homologation of precursor 66 in the synthesize C1–C11 fragment 61 of borrelidin [39].
Scheme 11: Synthesis of the C1–C11 fragment 61 of borrelidin from monoalcohol 65 [39].
Scheme 12: Synthetic plan for Theodorakis’ C3–C11 fragment 82 of borrelidin by Laschat et al. [38].
Scheme 13: Synthesis of Theodorakis’ C3–C11 fragment 82 from compound 88 [38].
Scheme 14: Retrosynthesis of 61 and 62b by Minnaard and Madduri [37].
Scheme 15: Synthesis of intermediate 98 by Minnaard and Madduri [37].
Scheme 16: Synthesis of Ōmura’s C1–C11 fragment 61 by Minnaard and Madduri [37].
Scheme 17: Synthesis of fragment 62b of borrelidin as proposed by Minnaard and Madduri [37].
Scheme 18: Iterative directed allylation for the synthesis of deoxypropionates by Herber and Breit [33].
Scheme 19: Iterative copper-mediated directed allyl substitution for the synthesis of Theodorakis’ C3–C11 frag...
Scheme 20: Retrosynthesis of the C3–C17 fragment of borrelidin by Iqbal and co-workers [35].
Scheme 21: Synthesis of key intermediates 137 and 147 for the synthesis of the C3–C17 fragment of borrelidin.
Scheme 22: Synthesis of the C3–C17 fragment 150a,b of borrelidin.
Scheme 23: Synthesis of the C11–C15 fragment 155a of borrelidin.
Scheme 24: Macrocyclization of borrelidin model compounds 155a and 155b using ring-closing metathesis.
A multicomponent reaction-initiated synthesis of imidazopyridine-fused isoquinolinones
- Ashutosh Nath,
- John Mark Awad and
- Wei Zhang
Beilstein J. Org. Chem. 2025, 21, 1161–1169, doi:10.3762/bjoc.21.92
Graphical Abstract
Figure 1: Bioactive compounds bearing imidazopyridine (red) and isoquinolinone-kind (blue) rings.
Scheme 1: GBB-initiated synthesis of imidazopyridine-fused isoquinolinones.
Scheme 2: GBB reaction and N-acylation for the preparation of imidazo[1,2-a]pyridines 6.
Scheme 3: Substrate scope for IMDA and dehydrative aromatization in making 8. Reaction conditions: 6 and AlCl3...
Figure 2: Transition state analysis of IMDA reactions for 6a, 6j, 6h and 6r.
Figure 3: Relative energy diagram for the synthesis of 8a from 6a.
Scheme 4: Using thiophene-2-carbaldehyde for the synthesis of 8t.
Scheme 5: Proposed mechanisms for IMDA reaction and dehydration re-aromatization.
Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters
- Carlos R. Azpilcueta-Nicolas and
- Jean-Philip Lumb
Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35
Graphical Abstract
Scheme 1: Comparison between Barton and NHPI ester radical precursors.
Scheme 2: Overview of the mechanisms and activation modes involved in radical generation from RAEs.
Scheme 3: Common mechanisms in photocatalysis.
Scheme 4: A) Giese-type radical addition of NHPI esters mediated by a reductive quenching photocatalytic cycl...
Scheme 5: A) Minisci-type radical addition of NHPI esters. B) Reaction mechanism involving an “off-cycle” red...
Scheme 6: Activation of NHPI esters through hydrogen-bonding in an oxidative quenching photocatalytic cycle.
Scheme 7: SET activation of RAE facilitated by a Lewis acid catalyst.
Scheme 8: PCET activation of NHPI esters in the context of a radical-redox annulation.
Scheme 9: Activation enabled by a strong excited-state reductant catalyst and its application in the dearomat...
Scheme 10: Proposed formation of an intramolecular charge-transfer complex in the synthesis of (spiro)anellate...
Scheme 11: Formation of a charge-transfer complex between enamides and NHPI esters enabled by a chiral phospha...
Scheme 12: Activation of NHPI ester through the formation of photoactive EDA-complexes.
Scheme 13: A) EDA complex-mediated radical hydroalkylation reactions of NHPI esters. B) Proposed mechanism for...
Scheme 14: Proposed radical chain mechanism initiated by EDA-complex formation.
Scheme 15: A) Photoinduced decarboxylative borylation. B) Proposed radical chain mechanism.
Scheme 16: A) Activation of NHPI esters mediated by PPh3/NaI. B) Proposed catalytic cycle involving EDA-comple...
Scheme 17: A) Radical generation facilitated by EDA complex formation between PTH1 catalyst and NHPI esters. B...
Scheme 18: Proposed catalytic cycle for the difunctionalization of styrenes.
Scheme 19: Formation of a charge-transfer complex between NHPI esters and Cs2CO3 enables decarboxylative amina...
Scheme 20: 3-Acetoxyquinuclidine as catalytic donor in the activation of TCNHPI esters.
Scheme 21: A) Photoinduced Cu-catalyzed decarboxylative amination. B) Proposed catalytic cycle. C) Radical clo...
Scheme 22: A) Photoinduced Pd-catalyzed aminoalkylation of 1,4-dienes. B) Proposed catalytic cycle.
Scheme 23: A) TM-catalyzed decarboxylative coupling of NHPI esters and organometallic reagents. B) Representat...
Scheme 24: Synthetic applications of the TM-catalyzed decarboxylative coupling of NHPI esters and organometall...
Scheme 25: A) Ni-catalyzed cross-electrophile coupling of NHPI esters. B) Representative catalytic cycle.
Scheme 26: A) Synthetic applications of decarboxylative cross-electrophile couplings. B) Decarboxylative aryla...
Scheme 27: A) Activation of tetrachlorophthalimide redox-active esters enabled by a low-valency Bi complex. B)...
Scheme 28: Activation of NHPI esters mediated by Zn0 applied in a Z-selective alkenylation reaction.
Scheme 29: A) Activation of NHPI esters enabled by a pyridine-boryl radical species applied to the decarboxyla...
Scheme 30: A) Decarboxylative coupling of RAE and aldehydes enabled by NHC-catalyzed radical relay. B) Propose...
Scheme 31: A) Decarboxylative C(sp3)–heteroatom coupling reaction of NHPI esters under NHC catalysis B) The NH...
Scheme 32: A) Electrochemical Giese-type radical addition of NHPI esters. B) Reaction mechanism.
Scheme 33: Electrochemical Minisci-type radical addition of NHPI-esters.
Scheme 34: Ni-electrocatalytic cross-electrophile coupling of NHPI esters with aryl iodides.
Scheme 35: A) Decarboxylative arylation of NHPI esters under Ag-Ni electrocatalysis B) Formation of AgNP on th...
Scheme 36: Synthetic applications of decarboxylative couplings of NHPI esters under Ni-electrocatalysis.
Scheme 37: Examples of natural product syntheses in which RAEs were used in key C–C bond forming reactions.
Enhancing chemical synthesis planning: automated quantum mechanics-based regioselectivity prediction for C–H activation with directing groups
- Julius Seumer,
- Nicolai Ree and
- Jan H. Jensen
Beilstein J. Org. Chem. 2025, 21, 1171–1182, doi:10.3762/bjoc.21.94
Graphical Abstract
Figure 1: Overview of the predictive workflow: For the shown substrate on the left, three unique activation s...
Figure 2: Example of the output from running the SMARTS pattern approach introduced by Tomberg et al. [9] with t...
Figure 3: An example where our algorithm found a more specific SMARTS pattern match than highlighted in Tombe...
Figure 4: An example highlighting the difficulties in prioritizing the SMARTS patterns. All three patterns ma...
Figure 5: Example of a combination of C–H bond and DG that is discarded because of the angle constraint on th...
Figure 6: Example of combinations of C–H bonds and DGs that are considered identical because of symmetry of t...
Figure 7: Example of combinations of C–H bonds and DGs that are considered identical because of symmetry of t...
Figure 8: Example of combinations of C–H bonds and DGs that are considered identical because of resonance str...
Figure 9: A: Distribution of correct (green) and wrong (red) predictions for molecules with two to five poten...
Figure 10: Molecules with five potential reaction sites that are predicted wrong by the QM workflow. The exper...
Figure 11: Predictions of reaction sites within a 1 kcal·mol−1 threshold for ten molecules are marked with a b...
Figure 12: Substrate with six potential unique reaction sites for C–H functionalization. The experimentally de...
Facile one-pot reduction of β-nitrostyrenes to phenethylamines using sodium borohydride and copper(II) chloride
- Laura D’Andrea and
- Simon Jademyr
Beilstein J. Org. Chem. 2025, 21, 39–46, doi:10.3762/bjoc.21.4
Graphical Abstract
Scheme 1: Brief comparison between the main traditional synthetic routes for the preparation of substituted p...
Figure 1: The β-nitrostyrene analogues used in this work.
Scheme 2: Additional products obtained via this method: nitrobenzene and methyl benzoate are reduced in excel...
Figure 2: Numerous masses (m/z) were detected by ESI-MS at T = 0 upon mixing all the reagents to produce 1b.
Figure 3: Structures of proposed adducts. Their masses, 254.2 and 242.2, respectively, were found at T = 0 by...
Scheme 3: Proposed mechanism for the formation of the hydroxylamine side product b. N-Phenethylhydroxylamine (...
Red light excitation: illuminating photocatalysis in a new spectrum
- Lucas Fortier,
- Corentin Lefebvre and
- Norbert Hoffmann
Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22
Graphical Abstract
Figure 1: Influence of the metal center M (Fe, Ru, Os) on the position of the MLCT and MC (metal-centered) ab...
Scheme 1: Red-light-mediated ring-closing metathesis through activation of a ruthenium catalyst by an osmium ...
Scheme 2: Photocatalyzed polymerization of dicylopentadiene mediated with red or blue light.
Figure 2: Comparison between [Ru(bpy)3]2+ and [Os(tpy)2]2+ in a photocatalyzed trifluoromethylation reaction:...
Scheme 3: Red-light photocatalyzed C–N cross-coupling reaction by T. Rovis et al. (SET = single-electron tran...
Figure 3: Red-light-mediated aryl oxidative addition with a bismuthinidene complex.
Scheme 4: Red-light-mediated reduction of aryl derivatives by O. S. Wenger et al. (PC = photocatalyst, anh = ...
Scheme 5: Red-light-mediated aryl halides reduction with an isoelectronic chromium complex (TDAE = tetrakis(d...
Scheme 6: Red-light-photocatalyzed trifluoromethylation of styrene derivatives with Umemoto’s reagent and a p...
Scheme 7: Red-light-mediated energy transfer for the cross-dehydrogenative coupling of N-phenyltetrahydroisoq...
Scheme 8: Red-light-mediated oxidative cyanation of tertiary amines with a phthalocyanin zinc complex.
Scheme 9: Formation of dialins and tetralins via a red-light-photocatalyzed reductive decarboxylation mediate...
Scheme 10: Oxidation of β-citronellol (28) via energy transfer mediated by a red-light activable silicon phtha...
Scheme 11: Formation of alcohol derivatives 32 from boron compounds 31 using chlorophyll (chl) as a red-light-...
Scheme 12: Red-light-driven reductive dehalogenation of α-halo ketones mediated by a thiaporphyrin photocataly...
Figure 4: Photoinduced electron transfer-reversible addition-fragmentation chain transfer polymerization medi...
Figure 5: Recent examples of red-light-mediated photocatalytic reactions with traditional organic dyes.
Figure 6: Squaraine photocatalysts used by Goddard et al. and aza-Henry reaction with squaraine-based photoca...
Figure 7: Reactions described by Goddard et al. involving 40 as the photocatalyst.
Figure 8: Various structures of squaraine derivatives used to initiate photopolymerizations.
Figure 9: Naturally occurring cyanins.
Figure 10: Influence of the structure on the photophysical properties of a cyanin dye.
Figure 11: NIR-light-mediated aza-Henry reaction photocatalyzed by 46.
Scheme 13: Photocatalyzed arylboronic acids oxidation by 46.
Figure 12: Cyanin structures synthetized and characterized by Goddard et al. (redox potentials given against s...
Figure 13: N,N′-Di-n-propyl-1,13-dimethoxyquinacridinium (55) with its redox potentials at its ground state an...
Scheme 14: Dual catalyzed C(sp2)–H arylation of 57 using DMQA 55 as the red-light-absorbing photocatalyst.
Scheme 15: Red-light-mediated aerobic oxidation of arylboronic acids 59 into phenols 60 via the use of DMQA as...
Figure 14: Red-light-photocatalyzed reactions proposed by Gianetti et al. using DMQA as the photocatalyst.
Scheme 16: Simultaneous release of NO and production of superoxide (O2•−) and their combination yielding the p...
Figure 15: Palladium porphyrin complex as the photoredox catalyst and the NO releasing substrate are linked in...
Scheme 17: Uncaging of compound 69 which is a microtubule depolymerizing agent using near IR irradiation. The ...
Scheme 18: Photochemical uncaging of drugs protected with a phenylboronic acid derivative using near IR irradi...
Scheme 19: Photoredox catalytical generation of aminyl radicals with near IR irradiation for the transfer of b...
Scheme 20: Photoredox catalytical fluoroalkylation of tryptophan moieties.
Figure 16: Simultaneous absorption of two photons of infrared light of low energy enables electronic excitatio...
Scheme 21: Uncaging Ca2+ ions using two-photon excitation with near infrared light.
A versatile route towards 6-arylpipecolic acids
- Erich Gebel,
- Cornelia Göcke,
- Carolin Gruner and
- Norbert Sewald
Beilstein J. Org. Chem. 2025, 21, 1104–1115, doi:10.3762/bjoc.21.88
Graphical Abstract
Scheme 1: ᴅ-2-Aminoadipic acid (1) can be used to generate C6 aryl and alkynyl-modified pipecolic acid deriva...
Scheme 2: Methyl ester formation, followed by cyclization, N-formylation, as well as bromination under Vilsme...
Scheme 3: Suzuki–Miyaura cross-coupling reaction between bromide 2 and a variety of boronic acids 8.
Scheme 4: Reaction of 3a to (2R,6S)-9a and (2R,6R)-9a. The chromatograms prove the simple diastereoselection.
Figure 1: The minor diastereomer of the catalytic hydrogenation was assigned as (2R,6R)-9, based on the analy...
Figure 2: 1H NMR spectra with both signal sets for the chair and half-chair configuration as well as Newman p...
Figure 3: 1H NMR spectra with signal set for the chair configuration as well as Newman projection for both pr...
Scheme 5: a) Sonogashira–Hagihara cross-coupling reaction followed by b) NaBH3CN reduction of the N-acylimini...
Figure 4: 1H NMR with Newman projection for both protons H2 and H6 with corresponding dihedral angles ϕ for a...
Scheme 6: Overview of reduction and deprotection to the final pipecolic acid derivatives (2R,6S)-5.
