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Search for "diol" in Full Text gives 402 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Oxetanes: formation, reactivity and total syntheses of natural products
- Peter Gabko,
- Martin Kalník and
- Maroš Bella
Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101
- transfer. In the second protocol, the β-lactone intermediates 7 are reduced to a diol and a subsequent Williamson etherification affords the oxetanes. Since both protocols consist of two steps and give only moderate yields, the overall oxetane yield and synthetic efficiency are rather low. In 2019, Marini
Graphical Abstract
Figure 1: Bond lengths and bond angles in oxetane at 140 K [2].
Figure 2: Analogy of 3-substituted oxetanes to carbonyl and gem-dimethyl groups [12].
Figure 3: Use of oxetanes in drug design – selected examples.
Figure 4: Examples of oxetane-containing natural products.
Scheme 1: Synthetic strategies towards construction of the oxetane ring.
Scheme 2: Overview of intramolecular Williamson etherification and competing Grob fragmentation.
Scheme 3: Synthesis of spiro-oxetanes via 1,4-C–H insertion and Williamson etherification.
Scheme 4: Use of phenyl vinyl selenone in the synthesis of spirooxindole oxetanes.
Scheme 5: Synthesis of bicyclic 3,5-anhydrofuranoses via double epoxide opening/etherification.
Scheme 6: Preparation of spirooxetanes by cycloisomerisation via MHAT/RPC.
Scheme 7: Oxetane synthesis via alcohol C–H functionalisation.
Scheme 8: Access to oxetanes 38 from α-acetyloxy iodides.
Scheme 9: The kilogram-scale synthesis of oxetane intermediate 41.
Scheme 10: Overview of the intramolecular opening of 3-membered rings.
Scheme 11: Synthesis of 4,7-dioxatricyclo[3.2.1.03,6]octane skeletons.
Scheme 12: Silicon-directed electrophilic cyclisation of homoallylic alcohols.
Scheme 13: Hydrosilylation–iodocyclisation of homopropargylic alcohols.
Scheme 14: Cu-catalysed intramolecular O-vinylation of γ-bromohomoallylic alcohols.
Scheme 15: Cu-catalysed intramolecular cross-coupling of hydroxyvinylstannanes.
Scheme 16: Isomerisation of oxiranyl ethers containing weakly carbanion-stabilising groups.
Scheme 17: Cyclisation of diethyl haloalkoxymalonates.
Scheme 18: Synthesis of oxetanes through a 1,5-HAT/radical recombination sequence.
Scheme 19: General approach to oxetanes via [2 + 2] cycloadditions.
Scheme 20: Synthesis of tricyclic 4:4:4 oxetanes through a photochemical triple cascade reaction.
Scheme 21: Iridium-catalysed Paternò–Büchi reaction between α-ketoesters and simple alkenes.
Scheme 22: Three-step synthesis of spirocyclic oxetanes 83 via Paternò–Büchi reaction, nucleophilic ring openi...
Scheme 23: Enantioselective Paternò–Büchi reaction catalysed by a chiral iridium photocatalyst.
Scheme 24: Synthesis of polysubstituted oxetanes 92 via Cu(II)-mediated formal [2 + 2] cycloadditions.
Scheme 25: Synthesis of alkylideneoxetanes via NHC- and DBU-mediated formal [2 + 2] cycloadditions.
Scheme 26: Use of sulphur-stabilised carbanions in ring expansions.
Scheme 27: Synthesis of α,α-difluoro(arylthio)methyl oxetanes.
Scheme 28: Ring expansion in an industrial synthesis of PF-06878031.
Scheme 29: Ring contraction of triflated 2-hydroxy-γ-lactones.
Scheme 30: Ring contraction in an industrial synthesis of PF-06878031.
Scheme 31: Photochemical ring contraction of 2,5-dihydrofurans by aryldiazoacetic acid esters.
Scheme 32: Synthesis of 3-oxetanones via O-H insertion of carbenes.
Scheme 33: Synthesis of phosphonate oxetanones via gold-mediated alkyne oxidation/O–H insertion.
Scheme 34: Syntheses and common derivatisations of 3-oxetanone.
Scheme 35: SN1 substitution of 3-aryloxetan-3-ols by thiols and alcohols.
Scheme 36: Fe–Ni dual-catalytic olefin hydroarylation towards 3-alkyl-3-(hetero)aryloxetanes.
Scheme 37: Synthesis of 3-aryloxetan-3-carboxylic acids.
Scheme 38: Decarboxylative alkylation of 3-aryloxetan-3-carboxylic acids.
Scheme 39: Synthesis of 3-amino-3-aryloxetanes via photoredox/nickel cross-coupling catalysis.
Scheme 40: Intermolecular cross-selective [2 + 2] photocycloaddition towards spirooxetanes.
Scheme 41: Synthesis of 3-aryl-3-aminooxetanes via defluorosulphonylative coupling.
Scheme 42: Two-step synthesis of amide bioisosteres via benzotriazolyl Mannich adducts 170.
Scheme 43: Functionalisation of oxetanyl trichloroacetimidates 172.
Scheme 44: Synthesis of oxetane-amino esters 176.
Scheme 45: Tandem Friedel–Crafts alkylation/intramolecular ring opening of 3-aryloxetan-3-ols.
Scheme 46: Synthesis of polysubstituted furans and pyrroles.
Scheme 47: Synthesis of oxazolines and bisoxazolines.
Scheme 48: Tandem, one-pot syntheses of various polycyclic heterocycles.
Scheme 49: Synthesis of 1,2-dihydroquinolines via skeletal reorganisation of oxetanes.
Scheme 50: Synthesis of benzoindolines and 2,3-dihydrobenzofurans and their derivatisations.
Scheme 51: Synthesis of polysubstituted 1,4-dioxanes.
Scheme 52: Preparation of various lactones via ring opening of oxetane-carboxylic acids 219.
Scheme 53: Tsuji-Trost allylation/ring opening of 3-aminooxetanes.
Scheme 54: Arylative skeletal rearrangement of 3-vinyloxetan-3-ols to 2,5-dihydrofurans.
Scheme 55: Reductive opening of oxetanes using catalytic Mg–H species.
Scheme 56: Opening of oxetanes by silyl ketene acetals.
Scheme 57: Rhodium-catalysed hydroacylation of oxetanes.
Scheme 58: Generation of radicals from oxetanes mediated by a vitamin B12-derived cobalt catalyst.
Scheme 59: Reductive opening of oxetanes by B–Si frustrated Lewis pairs.
Scheme 60: Zirconocene-mediated reductive opening of oxetanes.
Scheme 61: Enantioselective syntheses of small and medium-size rings using chiral phosphoric acids.
Scheme 62: Asymmetric synthesis of 2,3-dihydrobenzo[b]oxepines catalysed by a chiral scandium complex.
Scheme 63: Enantioselective synthesis of 1,3-bromohydrins under a chiral squaramide catalysis.
Scheme 64: Enantioselective opening of 2-aryl-2-ethynyloxetanes by anilines.
Scheme 65: Ru-catalysed insertion of diazocarbonyls into oxetanes.
Scheme 66: Ring expansion of oxetanes by stabilised carbenes generated under blue light irradiation.
Scheme 67: Expansion of oxetanes via nickel-catalysed insertion of alkynyltrifluoroborates.
Scheme 68: Nickel-catalysed expansion of oxetanes into ε-caprolactones.
Scheme 69: Expansion of oxetanes via cobalt-catalysed carbonyl insertion.
Scheme 70: Gold-catalysed intramolecular 1,1-carboalkoxylation of oxetane-ynamides.
Scheme 71: Expansion of oxetanes by stabilised sulphoxonium ylides.
Scheme 72: Cu-catalysed ring expansion of 2-vinyloxetanes by diazoesters.
Scheme 73: Total synthesis of (+)-oxetin.
Scheme 74: Total synthesis of racemic oxetanocin A.
Scheme 75: Total synthesis of (−)-merrilactone A.
Scheme 76: Total synthesis of (+)-dictyoxetane.
Scheme 77: Total synthesis of ent-dichrocephone B.
Scheme 78: Total synthesis of (−)-mitrephorone A.
Scheme 79: Total synthesis of (−)-taxol.
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
- with vinyl acetate as the acylating agent, Amano lipase AK (AKL) was identified as the most effective biocatalyst for achieving selective acetylation, converting diol 28 to the monoacetate 37 in 91% yield with >99.4% de (by HPLC). The diacetate byproduct 39 was formed in a small amount (9%). A similar
- diol desymmetrization of ent-28 was best achieved with Amano lipase PS (PSL), yielding monoacetate ent-37 (de 99.6%, 93% yield) without the formation of diacetate ent-39. Compound 37 was tosylated using tosyl chloride in pyridine with the addition of DMAP and the resulting product was treated with
- reduced with LiAlH4 to remove the OTs group, and after silyl group removal, diol 32b was obtained in 92% yield. Protection of the primary alcohol as a tosyl ester and the secondary as a TBDMS ether afforded intermediate 32c (72%). This intermediate was then treated with sodium thiophenol in ethanol
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.
Recent total synthesis of natural products leveraging a strategy of enamide cyclization
- Chun-Yu Mi,
- Jia-Yuan Zhai and
- Xiao-Ming Zhang
Beilstein J. Org. Chem. 2025, 21, 999–1009, doi:10.3762/bjoc.21.81
- cyclopentane ring, dihydroxylation, and oxidation of the diol to a diketone, produced intermediate 25 in its enol form. From this common intermediate, regioselective etherification at the less hindered position formed an enol ether. Final reduction of both the amide and the ketone using alane completed the
Graphical Abstract
Figure 1: Reactivity of enamides and enamide cyclizations.
Scheme 1: Total synthesis of (−)-dihydrolycopodine and (−)-lycopodine.
Scheme 2: Collective total synthesis of fawcettimine-type alkaloids.
Scheme 3: Total syntheses of cephalotaxine and cephalezomine H.
Scheme 4: Collective total syntheses of Cephalotaxus alkaloids.
Scheme 5: Asymmetric tandem cyclization/Pictet–Spengler reaction of tertiary enamides.
Scheme 6: Tandem cyclization/Pictet–Spengler reaction for the synthesis of chiral tetracyclic compounds.
Scheme 7: Total synthesis of (−)-cephalocyclidin A.
A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids
- Zhiyang Zhang,
- Jialei Hu,
- Hanfeng Ding,
- Li Zhang and
- Peirong Rao
Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75
- molecules could be synthesized from diol 9 through a late-stage modification involving adjustment of the oxidation state and regioselective acylation. The formation of 9 was envisioned to proceed via an intramolecular pinacol coupling [30][31] of [5,5,6,6]-tetracycle 10, which forges the A2 ring while
Graphical Abstract
Figure 1: Representative limonoid triterpenes.
Scheme 1: Structures and retrosynthetic analysis of krishnolides A (7) and C (8).
Scheme 2: Construction of α-iodoenone 13.
Scheme 3: Construction of aldehyde 14.
Scheme 4: Synthesis of the advanced intermediate 10 (in the X ray structure of 10 solvent molecule is omitted...
Dicarboxylate recognition based on ultracycle hosts through cooperative hydrogen bonding and anion–π interactions
- Wen-Hui Mi,
- Teng-Yu Huang,
- Xu-Dong Wang,
- Yu-Fei Ao,
- Qi-Qiang Wang and
- De-Xian Wang
Beilstein J. Org. Chem. 2025, 21, 884–889, doi:10.3762/bjoc.21.72
- [29][31]. A one-pot reaction of submacrocycle 1a and 2-(benzyloxy)benzene-1,3-diol (2a) in the presence of 8.0 equivalents of CsF yielded the ultracycle precursor compounds. Three reorganized products B4a, B5a, and B6a with different ring sizes were isolated. As previously observed, the structural
Graphical Abstract
Scheme 1: Synthesis of ultracycles.
Figure 1: (a, b) Crystal structure of B4aH (hydrogen atoms are omitted for clarity), and (c) the stacking str...
Figure 2: (a) The structures of host and guests, (b) 1H NMR spectra (298 K, 400 MHz, CD3CN) of B4aH upon titr...
Figure 3: (a–c) DFT-optimized structure of the B4aH-C72− complex. The blue dotted lines represent hydrogen bo...
Cryptophycin unit B analogues
- Thomas Schachtsiek,
- Jona Voss,
- Maren Hamsen,
- Beate Neumann,
- Hans-Georg Stammler and
- Norbert Sewald
Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40
- acidolysis was followed by macrolactamisation to obtain diol 24, albeit in poor yield of 11%. LC–MS analyses revealed that the low yield cannot be attributed to either incomplete acidolysis or incomplete conversion of the deprotected seco-cryptophycin during macrolactamisation. Rather, LC–MS analyses
- indicate the major presence of a fully deprotected and trifluoroacetylated seco-cryptophycin, most likely a TFA ester of one of the free hydroxy groups, a finding which might reason the comparably low yields (21–25%) of structurally similar unit B analogues reported earlier [21]. Contrary, diol 25 was
- obtained through Grubbs metathesis and subsequent acetonide cleavage in a superior yield of 76%. The finalising steps to obtain epoxides 26 and 2 (Scheme 3) were a diol–epoxide transformation [11][19][32], including firstly the formation of a cyclic orthoester, secondly the formation of a bromohydrin
Graphical Abstract
Figure 1: A: Structure of cryptophycin-52. B: Cryptophycin-52 derivatives modified with conjugation handles i...
Scheme 1: Synthesis of modified unit B derivatives. a) HNO3, H2SO4, 0 °C, 5 h, 48% (isolated as monohydrate);...
Figure 2: Molecular structure of Boc-ᴅ-Phe(4-NHMe)-OMe 7 as determined by single-crystal X-ray diffraction me...
Scheme 2: Synthesis of cryptophycin diols 24 and 25. a) EDC·HCl, DMAP, NEt3, CH2Cl2, 0 °C to rt, 22 h, 60%; b...
Scheme 3: Three-step diol–epoxide transformation starting from diols 24 and 25. a) (MeO)3CH, pyridinium p-tol...
Synthesis of electrophile-tethered preQ1 analogs for covalent attachment to preQ1 RNA
- Laurin Flemmich and
- Ronald Micura
Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35
- 3b in almost quantitative yield. The bis(3-bromopropyl)-modified ligand 3c was generated by heating preQ1 together with bis(3-hydroxypropyl)amine. It is noteworthy that the amine exchange reaction is thought to proceed via a purine methide intermediate [11]. Subsequent treatment of the diol with
Graphical Abstract
Scheme 1: A) Chemical structures of hypermodified nucleobase queuine and nucleoside queuosine (Q) occurring a...
Scheme 2: Three-step syntheses of preQ1 (1) and DPQ1 (2). For the synthesis of m6preQ1 (16) see Supporting Information File 1.
Scheme 3: Syntheses of haloalkyl- and mesyloxyalkyl-modified preQ1 as and DPQ1 ligands.
Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions
- Francesco Mele,
- Ana M. Constantin,
- Andrea Porcheddu,
- Raimondo Maggi,
- Giovanni Maestri,
- Nicola Della Ca’ and
- Luca Capaldo
Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33
- shaking a 1:1 mixture of chalcone (4.1) and 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol (4.2) with a test-tube shaker under irradiation with a high-pressure Hg lamp, the [2 + 2] syn-head-to-tail dimer product 4.3 was obtained selectively in 80% yield after 10 h (Scheme 4) [66]. In detail, 4.2 works as a
Graphical Abstract
Figure 1: The Grotthuss–Draper, Einstein–Stark, and Beer–Lambert laws. T: transmittance; ε: molar attenuation...
Figure 2: The benefits of merging photochemistry with mechanochemical setups (top). Most common setups for ph...
Scheme 1: Mechanochemically triggered pedal-like motion in solid-state [2 + 2] photochemical cycloaddition fo...
Scheme 2: Mechanically promoted [2 + 2] photodimerization of trans-1,2-bis(4-pyridyl)ethylene (2.1) via supra...
Scheme 3: Photo-thermo-mechanosynthesis of quinolines [65].
Scheme 4: Study of the mechanically assisted [2 + 2] photodimerization of chalcone [66].
Scheme 5: Liquid-assisted vortex grinding (LAVG) for the synthesis of [2.2]paracyclophane [68].
Scheme 6: Photomechanochemical approach for the riboflavin tetraacetate-catalyzed photocatalytic oxidation of...
Scheme 7: Photomechanochemical oxidation of 1,2-diphenylethyne to benzil. The photo in Scheme 7 was republished with ...
Scheme 8: Photomechanochemical borylation of aryldiazonium salts. The photo in Scheme 8 was reproduced from [72] (© 2017 ...
Scheme 9: Photomechanochemical control over stereoselectivity in the [2 + 2] dimerization of acenaphthylene. ...
Scheme 10: Photomechanochemical synthesis of polyaromatic compounds using UV light. The photo in Scheme 10 was reproduc...
Scheme 11: Mechanically assisted photocatalytic reactions: A) atom-transfer-radical addition, B) pinacol coupl...
Scheme 12: Use of mechanoluminescent materials as photon sources for photomechanochemistry. SAOED: SrAl2O4:Eu2+...
Figure 3: SWOT (strengths, weaknesses, opportunities, threats) analysis of photomechanochemistry.
Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates
- Kirill A. Gomonov,
- Vasilii V. Pelipko,
- Igor A. Litvinov,
- Ilya A. Pilipenko,
- Anna M. Stepanova,
- Nikolai A. Lapatin,
- Ruslan I. Baichurin and
- Sergei V. Makarenko
Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24
- furopyran, furocoumarin [9][10], and furopyrimidine series [11][12]. It is known that the main approaches to the synthesis of naphtho[2,3-b]furan-4,9-diones are reactions of hydroxynaphthalene-1,4-dione with ethane-1,2-diol [13], chloroacetaldehyde [14], ethenyl methyl sulfone [15], or ethenyl acetate [16
Graphical Abstract
Scheme 1: Approaches to the synthesis of naphtho[2,3-b]furan-4,9-diones.
Scheme 2: Approaches to the synthesis of furo[2,3-d]pyrimidin-4(3H)-ones.
Scheme 3: Approaches to the synthesis of furan-containing pyranopyrans and pyranochromenes.
Scheme 4: Reaction of alkyl 3-bromo-3-nitroacrylates 1a,b with 2-hydroxynaphthalene-1,4-dione (2a).
Scheme 5: Reaction of alkyl 3-bromo-3-nitroacrylates 1a,b with 4-hydroxy-7,7-dimethyl-7,8-dihydro-2H-1-benzop...
Scheme 6: Reaction of alkyl 3-bromo-3-nitroacrylates 1a,b with 4-hydroxy-7-methyl-2H,5H-pyrano[4,3-b]pyran-2,...
Scheme 7: Reaction of alkyl 3-bromo-3-nitroacrylates 1a,b with pyrimidine-4,6-diols 2e–g.
Discovery of ianthelliformisamines D–G from the sponge Suberea ianthelliformis and the total synthesis of ianthelliformisamine D
- Sasha Hayes,
- Yaoying Lu,
- Bernd H. A. Rehm and
- Rohan A. Davis
Beilstein J. Org. Chem. 2024, 20, 3205–3214, doi:10.3762/bjoc.20.266
- ETD ESI-qTOF. Alltech Davisil (30–40 µm, 60 Å) C8-bonded silica and Alltech Davisil (30–40 µm, 60 Å) diol-bonded silica were used for pre-adsorption work before RP- or NP-HPLC, respectively. The pre-adsorbed material was subsequently packed into an Alltech stainless steel guard cartridge (10 × 30 mm
- phenyl-bonded silica (5 μm, 100 Å, 150 × 21.2 mm) and Phenomenex Luna C18 column (5 µm, 90–110 Å, 10 mm × 250 mm) were used for RP-HPLC separations. For NP-HPLC, a YMC diol-bonded silica (5 μm, 120 Å, 150 × 20 mm) column was used. The frozen marine sponge was dried using a Dynamic FD12 freeze dryer and
Graphical Abstract
Figure 1: Chemical structures of ianthelliformisamines A–G (1–7) and aplysterol (8).
Figure 2:
Key COSY (![[Graphic 1]](/bjoc/content/inline/1860-5397-20-266-i2.svg?max-width=637&scale=1.18182)
), HMBC (![[Graphic 2]](/bjoc/content/inline/1860-5397-20-266-i3.svg?max-width=637&scale=1.18182)
) and ROESY (![[Graphic 3]](/bjoc/content/inline/1860-5397-20-266-i4.svg?max-width=637&scale=1.18182)
) correlations for ianthelliformisamines D (4) and E (5).
Figure 3:
Key COSY (![[Graphic 4]](/bjoc/content/inline/1860-5397-20-266-i5.svg?max-width=637&scale=1.18182)
) and HMBC (![[Graphic 5]](/bjoc/content/inline/1860-5397-20-266-i6.svg?max-width=637&scale=1.18182)
) correlations for ianthelliformisamines F (6) and G (7).
Scheme 1: Total synthesis of ianthelliformisamine D (4).
Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures
- Yosuke Akae
Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252
- , [3]rotaxane diol 10 was used as the initiator of the controlled ring-opening polymerization (ROP) of ε-caprolactone in the presence of a diphenyl phosphate catalyst to introduce the polyester main chain into the rotaxane framework; the successive end-capping reactions yielded macromolecular [3
- ]rotaxane 11 (Figure 12). In this synthesis, the hydroxy groups on CDs were completely acetylated to facilitate ROP only from the axle-end diol moieties and increase the solubility of [3]rotaxane. Further, subjecting the polymer to heat treatment induced the deslipping of CDs from the central alkyl chain on
Graphical Abstract
Figure 1: Overview of the CD-based rotaxane as a polymer material covered in this review.
Figure 2: CD structure.
Figure 3: Typical pathway for synthesizing CD-based rotaxanes.
Scheme 1: (A) Synthesis of α-CD-based [2]rotaxane via a metal–ligand complex. (B) Chemical structures of meth...
Scheme 2: Synthesis of α-CD-based polyrotaxane.
Scheme 3: Facile [3]rotaxane synthesis by the urea end-capping method.
Figure 4: (A) Single-crystal structure of α-CD-based [3]rotaxane 3 and PMα-CD-based [3]rotaxane 4. (B) Schema...
Figure 5: Structural control of CD-based [2]rotaxane via (A) light irradiation and (B) light irradiation and ...
Figure 6: Relationship among the plus–minus signs of ICD, the position of the guest molecule, and the axis of...
Figure 7: Structural control of CD-based rotaxane via (A) redox reaction and (B) in a solvent.
Scheme 4: (A) Synthesis of pseudopolyrotaxane bearing an ABA triblock copolymer as an axle. (B) Two synthetic...
Scheme 5: Slippage of size-complementary rotaxanes.
Figure 8: (A) Reversible formation of the CD-based [2]rotaxane. (B) Deslipping reaction of the CD-based size-...
Figure 9: (A) Chemical structures of [3]rotaxanes 2 and 3. (B) Schematic of the deslipping reaction of [3]rot...
Figure 10: (A) Modification of the axle ends of [3]rotaxane by (1) bromination and (2) the Suzuki coupling rea...
Figure 11: (A) ICD spectra of [3]rotaxanes bearing acylated (top) and conventional (bottom) CDs. (B) Schematic...
Figure 12: Synthesis of macromolecular[3]rotaxane via a size-complementary protocol.
Figure 13: Conjugated polymer insulated by (A) β-CD. (B) Triphenylamine-substituted β-CD.
Figure 14: Synthesis of the VSC and successive rotaxane-crosslinked polymer (RCP) preparation.
Figure 15: (A) Chemical structure of the [3]rotaxane crosslinker (RC). (B) Schematic of the synthesis and de-c...
Figure 16: (A) Random vinylation of the CD-based [3]rotaxane; (B) Schematic of the reaction between α-CD and m...
Figure 17: (A) Aggregation of CD-based [3]rotaxane. (B) Schematic of the plausible mechanism of the aggregatio...
4,6-Diaryl-5,5-difluoro-1,3-dioxanes as chiral dopants for liquid crystal compositions
- Maurice Médebielle,
- Peer Kirsch,
- Jérémy Merad,
- Carolina von Essen,
- Clemens Kühn and
- Andreas Ruhl
Beilstein J. Org. Chem. 2024, 20, 2940–2945, doi:10.3762/bjoc.20.246
- range of chiral, twisted molecules such as binaphthyls [23][24][25], biphenyls [26][27], TADDOLs [16][17] and 1,2-diphenylethane-1,2-diol [28] to reveal possible relationships between the molecular structure of chiral dopants and their HTP value. However, quantitative structure–property relationships
- still remain elusive and are not well understood [29]. Recently we have become interested in the preparation of racemic [30] anti- and highly enantioenriched 2,2-difluoro-1,3-diols [30][31][32] through an acylative double catalytic kinetic resolution (DoCKR) process [33]. While the 1,3-diol motif is
- -1,3-diphenyl-1,3-propanediol (rac-2). These enantiomers were then evaluated as chiral dopants using two commercially available liquid crystal host mixtures (Host 1 and Host 2 from Merck KGaA) (Scheme 2). Results and Discussion Racemic anti-2,2-difluoro-1,3-diol rac-2 was easily prepared through a
Graphical Abstract
Figure 1: Selected examples of chiral dopants with high HTPs in their nematic host LC mixture.
Scheme 1: Structure–property relationship of 4,6-diheteroaryl-5,5-difluoro-1,3-dioxanes as potential chiral d...
Scheme 2: The syntheses of chiral 4,6-diphenyl-5,5-difluoro-1,3-dioxanes 3 and 4 as dopants for cholesteric l...
Scheme 3: Synthesis of rac-2 as precursor of rac-3 and rac-4.
Figure 2: Configuration of (R,R)-3 determined by X-ray crystallography.
Figure 3: Configuration of (R,R)-4 determined by X-ray crystallography.
The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)
- Cristina Martini,
- Muhammad Idham Darussalam Mardjan and
- Andrea Basso
Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162
- underwent cyclization and dehydration to produce linked polyheterocyclic indoles 75. The authors managed to prepare five adducts in 15–33% yield. Another mechanistic scenario occurred at higher temperature (Scheme 25, conditions b). The secondary amine of diol 73 substituted both secondary alcohols to
Graphical Abstract
Scheme 1: Mechanism of the GBB reaction.
Scheme 2: Comparison of the performance of Sc(OTf)3 with some RE(OTf)3 in a model GBB reaction. Conditions: a...
Scheme 3: Comparison of the performance of various Brønsted acid catalysts in the synthesis of GBB adduct 6. ...
Scheme 4: Synthesis of Brønsted acidic ionic liquid catalyst 7. Conditions: a) neat, 60 °C, 24 h; b) TfOH, DC...
Scheme 5: Aryliodonium derivatives as organic catalysts in the GBB reaction. In the box the proposed binding ...
Scheme 6: DNA-encoded GBB reaction in micelles made of amphiphilic polymer 13. Conditions: a) 13 (50 equiv), ...
Scheme 7: GBB reaction catalyzed by cyclodextrin derivative 14. Conditions: a) 14 (1 mol %), water, 100 °C, 4...
Scheme 8: Proposed mode of activation of CALB. a) activation of the substrates; b) activation of the imine; c...
Scheme 9: One-pot GBB reaction–Suzuki coupling with a bifunctional hybrid biocatalyst. Conditions: a) Pd(0)-C...
Scheme 10: GBB reaction employing 5-HMF (23) as carbonyl component. Conditions: a) TFA (20 mol %), EtOH, 60 °C...
Scheme 11: GBB reaction with β-C-glucopyranosyl aldehyde 26. Conditions: a) InCl3 (20 mol %), MeOH, 70 °C, 2–3...
Scheme 12: GBB reaction with diacetylated 5-formyldeoxyuridine 29, followed by deacetylation of GBB adduct 30....
Scheme 13: GBB reaction with glycal aldehydes 32. Conditions: a) HFIP, 25 °C, 2–4 h.
Scheme 14: Vilsmeier–Haack formylation of 6-β-acetoxyvouacapane (34) and subsequent GBB reaction. Conditions: ...
Scheme 15: GBB reaction of 4-formlyl-PCP 37. Conditions: a) HOAc or HClO4, MeOH/DCM (2:3), rt, 3 d.
Scheme 16: GBB reaction with HexT-aldehyde 39. Conditions: a) 39 (20 nmol) and amidine (20 μmol), MeOH, rt, 6 ...
Scheme 17: GBB reaction of 2,4-diaminopirimidine 41. Conditions: a) Sc(OTf)3 (20 mol %), MeCN, 120 °C (MW), 1 ...
Scheme 18: Synthesis of N-edited guanine derivatives from 3,6-diamine-1,2,4-triazin-5-one 44. Conditions: a) S...
Scheme 19: Synthesis of 2-aminoimidazoles 49 by a Mannich-3CR followed by a one-pot intramolecular oxidative a...
Scheme 20: On DNA Suzuki–Miyaura reaction followed by GBB reaction. Conditions: a) CsOH, sSPhos-Pd-G2; b) AcOH...
Scheme 21: One-pot cascade synthesis of 5-iminoimidazoles. Conditions: a) Na2SO4, DMF, 220 °C (MW).
Scheme 22: GBB reaction of 5-amino-1H-imidazole-4-carbonile 57. Conditions: a) HClO4 (5 mol %), MeOH, rt, 24 h....
Scheme 23: One-pot cascade synthesis of indole-imidazo[1,2,a]pyridine hybrids. In blue the structural motif in...
Scheme 24: One-pot cascade synthesis of fused polycyclic indoles 67 or 69 from indole-3-carbaldehyde. Conditio...
Scheme 25: One-pot cascade synthesis of linked- and bridged polycyclic indoles from indole-2-carbaldehyde (70)...
Scheme 26: One-pot cascade synthesis of pentacyclic dihydroisoquinolines (X = N or CH). In blue the structural...
Scheme 27: One-pot stepwise synthesis of imidazopyridine-fused benzodiazepines 85. Conditions: a) p-TsOH (20 m...
Scheme 28: One-pot stepwise synthesis of benzoxazepinium-fused imidazothiazoles 89. Conditions: a) Yb(OTf)3 (2...
Scheme 29: One-pot stepwise synthesis of fused imidazo[4,5,b]pyridines 95. Conditions: a) HClO4, MeOH, rt, ove...
Scheme 30: Synthesis of heterocyclic polymers via the GBB reaction. Conditions: a) p-TsOH, EtOH, 70 °C, 24 h.
Scheme 31: One-pot multicomponent reaction towards the synthesis of covalent organic frameworks via the GBB re...
Scheme 32: One-pot multicomponent reaction towards the synthesis of covalent organic frameworks via the GBB re...
Scheme 33: GBB-like multicomponent reaction towards the synthesis of benzothiazolpyrroles (X = S) and benzoxaz...
Scheme 34: GBB-like multicomponent reaction towards the formation of imidazo[1,2,a]pyridines. Conditions: a) I2...
Scheme 35: Post-functionalization of GBB products via Ugi reaction. Conditions a) HClO4, DMF, rt, 24 h; b) MeO...
Scheme 36: Post-functionalization of GBB products via Click reaction. Conditions: a) solvent-free, 150 °C, 24 ...
Scheme 37: Post-functionalization of GBB products via cascade alkyne–allene isomerization–intramolecular nucle...
Scheme 38: Post-functionalization of GBB products via metal-catalyzed intramolecular N-arylation. In red and b...
Scheme 39: Post-functionalization of GBB products via isocyanide insertion (X = N or CH). Conditions: a) HClO4...
Scheme 40: Post-functionalization of GBB products via intramolecular nucleophilic addition to nitriles. Condit...
Scheme 41: Post-functionalization of GBB products via Pictet–Spengler cyclization. Conditions: a) 4 N HCl/diox...
Scheme 42: Post-functionalization of GBB products via O-alkylation. Conditions: a) TFA (20 mol %), EtOH, 120 °...
Scheme 43: Post-functionalization of GBB products via macrocyclization (X = -CH2CH2O-, -CH2-, -(CH2)4-). Condi...
Figure 1: Antibacterial activity of GBB-Ugi adducts 113 on both Gram-negative and Gram-positive strains.
Scheme 44: GBB multicomponent reaction using trimethoprim as the precursor. Conditions: a) Yb(OTf)3 or Y(OTf)3...
Figure 2: Antibacterial activity of GBB adducts 152 against MRSA and VRE; NA = not available.
Figure 3: Antibacterial activity of GBB adduct 153 against Leishmania amazonensis promastigotes and amastigot...
Figure 4: Antiviral and anticancer evaluation of the GBB adducts 154a and 154b. In vitro antiproliferative ac...
Figure 5: Anticancer activity of the GBB-furoxan hybrids 145b, 145c and 145d determined through antiprolifera...
Scheme 45: Synthesis and anticancer activity of the GBB-gossypol conjugates. Conditions: a) Sc(OTf)3 (10 mol %...
Figure 6: Anticancer activity of polyheterocycles 133a and 136a against human neuroblastoma. Clonogenic assay...
Figure 7: Development of GBB-adducts 158a and 158b as PD-L1 antagonists. HTRF assays were carried out against...
Figure 8: Development of imidazo[1,2-a]pyridines and imidazo[1,2-a]pyrazines as TDP1 inhibitors. The SMM meth...
Figure 9: GBB adducts 164a–c as anticancer through in vitro HDACs inhibition assays. Additional cytotoxic ass...
Figure 10: GBB adducts 165, 166a and 166b as anti-inflammatory agents through HDAC6 inhibition; NA = not avail...
Scheme 46: GBB reaction of triphenylamine 167. Conditions: a) NH4Cl (10 mol %), MeOH, 80 °C (MW), 1 h.
Scheme 47: 1) Modified GBB-3CR. Conditions: a) TMSCN (1.0 equiv), Sc(OTf)3 (0.2 equiv), MeOH, 140 °C (MW), 20 ...
Scheme 48: GBB reaction to assemble imidazo-fused heterocycle dimers 172. Conditions: a) Sc(OTf)3 (20 mol %), ...
Figure 11: Model compounds 173 and 174, used to study the acid/base-triggered reversible fluorescence response...
Syntheses and medicinal chemistry of spiro heterocyclic steroids
- Laura L. Romero-Hernández,
- Ana Isabel Ahuja-Casarín,
- Penélope Merino-Montiel,
- Sara Montiel-Smith,
- José Luis Vega-Báez and
- Jesús Sandoval-Ramírez
Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152
- diol 141 with chloroacetyl chloride, followed by cyclization induced by formation of the alcoholate. On the other hand, amino diol 141b was N-alkylated with methyl bromoacetate and then microwaved in the presence of potassium carbonate to obtain morpholinone 144 (Scheme 38). Romero-Hernández and Merino
Graphical Abstract
Figure 1: Steroidal spiro heterocycles with remarkable pharmacological activity.
Scheme 1: Synthesis of the spirooxetanone 2. a) t-BuOK, THF, rt, 16%.
Scheme 2: Synthesis of the 17-spirooxetane derivative 7. a) HC≡C(CH2)2CH2OTBDPS, n-BuLi, THF, BF3·Et2O, −78 °...
Scheme 3: Pd-catalyzed carbonylation of steroidal alkynols to produce α-methylene-β-lactones at C-3 and C-17 ...
Scheme 4: Catalyst-free protocol to obtain functionalized spiro-lactones by an intramolecular C–H insertion. ...
Scheme 5: One-pot procedure from dienamides to spiro-β-lactams. a) 1. Ac2O, DMAP, Et3N, CH2Cl2, 2. malononitr...
Scheme 6: Spiro-γ-lactone 20 afforded from 7α-alkanamidoestrone derivative 17. a) HC≡CCH2OTHP, n-BuLi, THF, –...
Scheme 7: Synthesis of the 17-spiro-γ-lactone 23, a key intermediate to obtain spironolactone. a) Ethyl propi...
Scheme 8: Synthetic pathway to obtain 17-spirodihydrofuran-3(2H)-ones from 17-oxosteroids. a) 1-Methoxypropa-...
Scheme 9: One-pot procedure to obtain 17-spiro-2H-furan-3-one compounds. a) NaH, diethyl oxalate, benzene, rt...
Scheme 10: Synthesis of 17-spiro-2H-furan-3-one derivatives. a) RCH=NOH, N-chlorosuccinimide/CHCl3, 99%; b) H2...
Scheme 11: Intramolecular condensation of a γ-acetoxy-β-ketoester to synthesize spirofuranone 37. a) (CH3CN)2P...
Scheme 12: Synthesis of spiro 2,5-dihydrofuran derivatives. a) Allyl bromide, DMF, NaH, 0 °C to rt, 93%; b) G-...
Scheme 13: First reported synthesis of C-16 dispiropyrrolidine derivatives. a) Sarcosine, isatin, MeOH, reflux...
Scheme 14: Cycloadducts 47 with antiproliferative activity against human cancer cell lines. a) 1,4-Dioxane–MeO...
Scheme 15: Spiropyrrolidine compounds generated from (E)-16-arylidene steroids and different ylides. a) Acenap...
Scheme 16: 3-Spiropyrrolidines 52a–c obtained from ketones 50a–c. a) p-Toluenesulfonyl hydrazide, MeOH, rt; b)...
Scheme 17: 16-Spiropyrazolines from 16-methylene-13α-estrone derivatives. a) AgOAc, toluene, rt, 78–81%.
Scheme 18: 6-Spiroimidazolines 57 synthesized by a one-pot multicomponent reaction. a) R3-NC, T3P®, DMSO, 70 °...
Scheme 19: Synthesis of spiro-1,3-oxazolines 60, tested as progesterone receptor antagonist agents. a) CF3COCF3...
Scheme 20: Synthesis of spiro-1,3-oxazolidin-2-ones 63 and 66a,b. a) RNH2, EtOH, 70 °C, 70–90%; b) (CCl3O)2CO,...
Scheme 21: Formation of spiro 1,3-oxazolidin-2-one and spiro 2-substituted amino-4,5-dihydro-1,3-oxazoles from ...
Scheme 22: Synthesis of diastereomeric spiroisoxazolines 74 and 75. a) Ar-C(Cl)=N-OH, DIPEA, toluene, rt, 74 (...
Scheme 23: Spiro 1,3-thiazolidine derivatives 77–79 obtained from 2α-bromo-5α-cholestan-3-one 76. a) 2-aminoet...
Scheme 24: Method for the preparation of derivative 83. a) Benzaldehyde, MeOH, reflux, 77%; b) thioglycolic ac...
Scheme 25: Synthesis of spiro 1,3-thiazolidin-4-one derivatives from steroidal ketones. a) Aniline, EtOH, refl...
Scheme 26: Synthesis of spiro N-aryl-1,3-thiazolidin-4-one derivatives 91 and 92. a) Sulfanilamide, DMF, reflu...
Scheme 27: 1,2,4-Trithiolane dimers 94a–e selectively obtained from carbonyl derivatives. a) LR, CH2Cl2, reflu...
Scheme 28: Spiro 1,2,4-triazolidin-3-ones synthesized from semicarbazones. a) H2O2, CHCl3, 0 °C, 82–85%.
Scheme 29: Steroidal spiro-1,3,4-oxadiazoline 99 obtained in two steps from cholest-5-en-3-one (97). a) NH2NHC...
Scheme 30: Synthesis of spiro-1,3,4-thiadiazoline 101 by cyclization and diacetylation of thiosemicarbazone 100...
Scheme 31: Mono- and bis(1,3,4-thiadiazolines) obtained from estrane and androstane derivatives. a) H2NCSNHNH2...
Scheme 32: Different reaction conditions to synthesize spiro-1,3,2-oxathiaphospholanes 108 and 109.
Scheme 33: Spiro-δ-lactones derived from ADT and epi-ADT as inhibitors of 17β-HSDs. a) CH≡C(CH2)2OTHP, n-BuLi,...
Scheme 34: Spiro-δ-lactams 123a,b obtained in a five-step reaction sequence. a) (R)-(+)-tert-butylsulfinamide,...
Scheme 35: Steroid-coumarin conjugates as fluorescent DHT analogues to study 17-oxidoreductases for androgen m...
Scheme 36: 17-Spiro estradiolmorpholinones 130 bearing two types of molecular diversity. a) ʟ- or ᴅ-amino acid...
Scheme 37: Steroidal spiromorpholinones as inhibitors of enzyme 17β-HSD3. a) Methyl ester of ʟ- or ᴅ-leucine, ...
Scheme 38: Steroidal spiro-morpholin-3-ones achieved by N-alkylation or N-acylation of amino diols 141, follow...
Scheme 39: Straightforward method to synthesize a spiromorpholinone derivative from estrone. a) BnBr, K2CO3, CH...
Scheme 40: Pyrazolo[4,3-e][1,2,4]-triazine derivatives 152–154. a) 4-Aminoantipyrine, EtOH/DMF, reflux, 82%; b...
Scheme 41: One-pot procedure to synthesize spiro-1,3,4-thiadiazine derivatives. a) NH2NHCSCONHR, H2SO4, dioxan...
Scheme 42: 1,2,4-Trioxanes with antimalarial activity. a) 1. O2, methylene blue, CH3CN, 500 W tungsten halogen...
Scheme 43: Tetraoxanes 167 and 168 synthesized from ketones 163, 165 and 166. a) NaOH, iPrOH/H2O, 80 °C, 93%; ...
Scheme 44: 1,2,4,5-Tetraoxanes bearing a steroidal moiety and a cycloalkane. a) 30% H2O2/CH2Cl2/CH3CN, HCl, rt...
Scheme 45: Spiro-1,3,2-dioxaphosphorinanes obtained from estrone derivatives. a) KBH4, MeOH, THF or CH2Cl2; b)...
Scheme 46: Synthesis of steroidal spiro-ε-lactone 183. a) 1. Jones reagent, acetone, 0 °C to rt, 2. ClCOCOCl, ...
Scheme 47: Synthesis of spiro-2,3,4,7-tetrahydrooxepines 185 and 187 derived from mestranol and lynestrenol (38...
Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations
- Ryo Tanifuji and
- Hiroki Oguri
Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151
- , introduce hydroxy groups at C8 and C16 to produce FD-8β,16-diol (7), and BscE-catalyzed O-methylation generates the putative intermediate 8. The subsequent oxidative allylic rearrangement (8→9), catalyzed by the nonheme iron(II) and 2-oxoglutarate (Fe(II)/2OG)-dependent dioxygenase BscD, was a key step
Graphical Abstract
Scheme 1: Targeted natural products and key enzymatic transformations in the chemo-enzymatic total syntheses ...
Scheme 2: Biosynthetic pathway to brassicicenes in Pseudocercospora fijiensis [14]. (A) Cyclization phase catalyz...
Scheme 3: Chemo-enzymatic total synthesis of cotylenol (1) and brassicicenes. (A) Chemical cyclization phase....
Scheme 4: (A) Biosynthetic pathway for trichodimerol (2) in Penicillium chrysogenum. (B) Chemo-enzymatic tota...
Scheme 5: (A) Proposed biosynthetic pathway for chalcomoracin (3) in Morus alba. (B) Outline of the biosynthe...
Scheme 6: (A) Chemo-enzymatically synthesized natural products by using the originally identified MaDA. (B) M...
Scheme 7: Proposed biosynthetic mechanism of tylactone (4) in Streptomyces fradiae.
Scheme 8: (A) Chemical synthesis and cascade enzymatic transformations of cyclization precursors. (B) Late-st...
Scheme 9: Proposed biosynthetic mechanism of saframycin A (5) in Streptomyces lavendulae.
Scheme 10: (A) Chemo-enzymatic total synthesis of saframycin A (5) and jorunnamycin A (103). (B) Chemo-enzymat...
Ring opening of photogenerated azetidinols as a strategy for the synthesis of aminodioxolanes
- Henning Maag,
- Daniel J. Lemcke and
- Johannes M. Wahl
Beilstein J. Org. Chem. 2024, 20, 1671–1676, doi:10.3762/bjoc.20.148
- 1), we successfully conducted the desired sequence by raising the temperature to 100 °C to initiate ring opening, and employing a mild transesterification method for diol release [43][44][45]. Thus, we were able to isolate 3-amino-1,2-diol 21 in 49% yield. Conclusion Within this work, we
Graphical Abstract
Scheme 1: Build and release approach for the functionalization of simple precursors. a) General overview. b) ...
Scheme 2: Modularity of the Norrish–Yang cyclization for the synthesis of azetidines.
Scheme 3: Ring-opening reactions using electron-deficient ketones and boronic acids.
Synthetic applications of the Cannizzaro reaction
- Bhaskar Chatterjee,
- Dhananjoy Mondal and
- Smritilekha Bera
Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120
- intramolecular Cannizzaro reaction while accomplishing the synthesis of the bicyclic core structure of proposed ottelione A (47) [85]. Commencing from the Diels–Alder adduct 48, an enzymatic desymmetrization of the reduced diol 49 formed the enantiopure 50 (ee >99%). A cascade of reaction sequences delivered the
- tetracyclic cage compound 51. Acetal opening in 51 afforded the keto-aldehyde 52 which underwent an intramolecular Cannizzaro reaction to give the trihydroxy acid 53, finally cyclizing to the lactone diol 54, elaboration of which led to the desired target (Scheme 18). An interesting application of the
- yield (92%) and formed the diol 77, after the removal of the Boc-protecting group, where the prochiral hydroxymethyl groups ultimately paved the way towards the natural products (Scheme 22). Bernhardson and coworkers developed a simple scalable route towards ertugliflozin (80), a C-glycoside containing
Graphical Abstract
Figure 1: Types and mechanism of the Cannizzaro reaction.
Figure 2: Various approaches of the Cannizzaro reaction.
Figure 3: Representative molecules synthesized via the Cannizzaro reaction.
Scheme 1: Intramolecular Cannizzaro reaction of aryl glyoxal hydrates using TOX catalysts.
Scheme 2: Intramolecular Cannizzaro reaction of aryl methyl ketones using ytterbium triflate/selenium dioxide....
Scheme 3: Intramolecular Cannizzaro reaction of aryl glyoxals using Cr(ClO4)3 as catalyst.
Scheme 4: Cu(II)-PhBox-catalyzed asymmetric Cannizzaro reaction.
Scheme 5: FeCl3-based chiral catalyst applied for the enantioselective intramolecular Cannizzaro reaction rep...
Scheme 6: Copper bis-oxazoline-catalysed intramolecular Cannizzaro reaction and proposed mechanism.
Scheme 7: Chiral Fe catalysts-mediated enantioselective Cannizzaro reaction.
Scheme 8: Ruthenium-catalyzed Cannizzaro reaction of aromatic aldehydes.
Scheme 9: MgBr2·Et2O-assisted Cannizzaro reaction of aldehydes.
Scheme 10: LiBr-catalyzed intermolecular Cannizzaro reaction of aldehydes.
Scheme 11: γ-Alumina as a catalyst in the Cannizzaro reaction.
Scheme 12: AlCl3-mediated Cannizzaro disproportionation of aldehydes.
Scheme 13: Ru–N-heterocyclic carbene catalyzed dehydrogenative synthesis of carboxylic acids.
Figure 4: Proposed catalytic cycle for the dehydrogenation of alcohols.
Scheme 14: Intramolecular desymmetrization of tetraethylene glycol.
Scheme 15: Desymmetrization of oligoethylene glycol dialdehydes.
Scheme 16: Intramolecular Cannizzaro reaction of calix[4]arene dialdehydes.
Scheme 17: Desymmetrization of dialdehydes of symmetrical crown ethers using Ba(OH)2.
Scheme 18: Synthesis of ottelione A (proposed) via intramolecular Cannizzaro reaction.
Scheme 19: Intramolecular Cannizzaro reaction for the synthesis of pestalalactone.
Scheme 20: Synthetic strategy towards nigricanin involving an intramolecular Cannizzaro reaction.
Scheme 21: Spiro-β-lactone-γ-lactam part of oxazolomycins via aldol crossed-Cannizzaro reaction.
Scheme 22: Synthesis of indole alkaloids via aldol crossed-Cannizzaro reaction.
Scheme 23: Aldol and crossed-Cannizzaro reaction towards the synthesis of ertuliflozin.
Scheme 24: Synthesis of cyclooctadieneones using a Cannizzaro reaction.
Scheme 25: Microwave-assisted crossed-Cannizzaro reaction for the synthesis of 3,3-disubstituted oxindoles.
Scheme 26: Synthesis of porphyrin-based rings using the Cannizzaro reaction.
Scheme 27: Synthesis of phthalides and pestalalactone via Cannizarro–Tishchenko-type reaction.
Scheme 28: Synthesis of dibenzoheptalene bislactones via a double intramolecular Cannizzaro reaction.
Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer
- Mohd Farhan Ansari,
- Atul Kumar Maurya,
- Abhishek Kumar and
- Saravanakumar Elangovan
Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98
- dehydrogenated secondary alcohols into ketone B and diol into aldehyde A. Further, aldol condensation occurred between the ketone and aldehyde and produced α,β-unsaturated ketone C, which was subsequently hydrogenated by complex Mn1-c, followed by allyl isomerization, which led to the formation of hydroxy ketone
- -membered ring products. They isolated cyclic five to seven-membered ring products by changing the lengths of the diols. For example, for the formation of cyclopentane products, butane-1,4-diol was used as the alcohol under the same reaction conditions, giving 31 to 70% yield of the desired products. Seven
- -membered rings were also formed only by changing the alcohols to hexane-1,6-diol under the same conditions as above, giving yields up to 80%. In addition, several ketones were investigated under these conditions with different diol systems, giving 55–80% yields of the cyclic products (Scheme 36). DFT
Graphical Abstract
Scheme 1: General scheme of the borrowing hydrogen (BH) or hydrogen auto-transfer (HA) methodology.
Scheme 2: General scheme for C–N bond formation. A) Traditional cross-couplings with alkyl or aryl halides. B...
Figure 1: Manganese pre-catalysts used for the N-alkylation of amines with alcohols.
Scheme 3: Manganese(I)-pincer complex Mn1 used for the N-alkylation of amines with alcohols and methanol.
Scheme 4: N-Methylation of amines with methanol using Mn2.
Scheme 5: C–N-Bond formation with amines and methanol using PN3P-Mn complex Mn3 reported by Sortais et al. [36]. a...
Scheme 6: Base-assisted synthesis of amines and imines with Mn4. Reaction assisted by A) t-BuOK and B) t-BuON...
Scheme 7: Coupling of alcohols and hydrazine via the HB approach reported by Milstein et al. [38]. aReaction time...
Scheme 8: Proposed mechanism for the coupling of alcohols and hydrazine catalyzed by Mn5.
Scheme 9: Phosphine-free manganese catalyst for N-alkylation of amines with alcohols reported by Balaraman an...
Scheme 10: N-Alkylation of sulfonamides with alcohols.
Scheme 11: Mn–NHC catalyst Mn6 applied for the N-alkylation of amines with alcohols. a3 mol % of Mn6 were used....
Scheme 12: N-Alkylation of amines with primary and secondary alcohols. a80 °C, b100 °C.
Scheme 13: Manganese(III)-porphyrin catalyst for synthesis of tertiary amines.
Scheme 14: Proposed mechanism for the alcohol dehydrogenation with Mn(III)-porphyrin complex Mn7.
Scheme 15: N-Methylation of nitroarenes with methanol using catalyst Mn3.
Scheme 16: Mechanism of manganese-catalyzed methylation of nitroarenes using Mn3 as the catalyst.
Scheme 17: Bidentate manganese complex Mn8 applied for the N-alkylation of primary anilines with alcohols. aOn...
Scheme 18: N-Alkylation of amines with alcohols in the presence of manganese salts and triphenylphosphine as t...
Scheme 19: N-Alkylation of diazo compounds with alcohols using catalyst Mn9.
Scheme 20: Proposed mechanism for the amination of alcohols with diazo compounds catalyzed by catalyst Mn9.
Scheme 21: Mn1 complex-catalyzed synthesis of polyethyleneimine from ethylene glycol and ethylenediamine.
Scheme 22: Bis-triazolylidene-manganese complex Mn10 for the N-alkylation of amines with alcohols.
Figure 2: Manganese complexes applied for C-alkylation reactions of ketones with alcohols.
Scheme 23: General scheme for the C–C bond formation with alcohols and ketones.
Scheme 24: Mn1 complex-catalyzed α-alkylation of ketones with primary alcohols.
Scheme 25: Mechanism for the Mn1-catalyzed alkylation of ketones with alcohols.
Scheme 26: Phosphine-free in situ-generated manganese catalyst for the α-alkylation of ketones with primary al...
Scheme 27: Plausible mechanism for the Mn-catalyzed α-alkylation of ketones with alcohols.
Scheme 28: α-Alkylation of esters, ketones, and amides using alcohols catalyzed by Mn11.
Scheme 29: Mono- and dialkylation of methylene ketones with primary alcohols using the Mn(acac)2/1,10-phenanth...
Scheme 30: Methylation of ketones with methanol and deuterated methanol.
Scheme 31: Methylation of ketones and esters with methanol. a50 mol % of t-BuOK were used, bCD3OD was used ins...
Scheme 32: Alkylation of ketones and secondary alcohols with primary alcohols using Mn4.
Scheme 33: Bidentate manganese-NHC complex Mn6 applied for the synthesis of alkylated ketones using alcohols.
Scheme 34: Mn1-catalyzed synthesis of substituted cycloalkanes by coupling diols and secondary alcohols or ket...
Scheme 35: Proposed mechanism for the synthesis of cycloalkanes via BH method.
Scheme 36: Synthesis of various cycloalkanes from methyl ketones and diols catalyze by Mn13. aReaction time wa...
Scheme 37: N,N-Amine–manganese complex (Mn13)-catalyzed alkylation of ketones with alcohols.
Scheme 38: Naphthyridine‑N‑oxide manganese complex Mn14 applied for the alkylation of ketones with alcohols. a...
Scheme 39: Proposed mechanism of the naphthyridine‑N‑oxide manganese complex (Mn14)-catalyzed alkylation of ke...
Scheme 40: α-Methylation of ketones and indoles with methanol using Mn15.
Scheme 41: α-Alkylation of ketones with primary alcohols using Mn16. aNMR yield.
Figure 3: Manganese complexes used for coupling of secondary and primary alcohols.
Scheme 42: Alkylation of secondary alcohols with primary alcohols catalyzed by phosphine-free catalyst Mn17. a...
Scheme 43: PNN-Manganese complex Mn18 for the alkylation of secondary alcohols with primary alcohols.
Scheme 44: Mechanism for the Mn-pincer catalyzed C-alkylation of secondary alcohols with primary alcohols.
Scheme 45: Upgrading of ethanol with methanol for isobutanol production.
Scheme 46: Mn-Pincer catalyst Mn19 applied for the β-methylation of alcohols with methanol. a2.0 mol % of Mn19...
Scheme 47: Functionalized ketones from primary and secondary alcohols catalyzed by Mn20. aMn20 (5 mol %), NaOH...
Scheme 48: Synthesis of γ-disubstituted alcohols and β-disubstituted ketones through Mn9-catalyzed coupling of...
Scheme 49: Proposed mechanism for the Mn9-catalyzed synthesis of γ-disubstituted alcohols and β-disubstituted ...
Scheme 50: Dehydrogenative coupling of ethylene glycol and primary alcohols catalyzed by Mn4.
Scheme 51: Mn18-cataylzed C-alkylation of unactivated esters and amides with alcohols.
Scheme 52: Alkylation of amides and esters using Mn21.
Scheme 53: α-Alkylation of nitriles with primary alcohols using in situ-generated manganese catalyst.
Scheme 54: Proposed mechanism for the α-alkylation of nitriles with primary alcohols.
Scheme 55: Mn9-catalyzed α-alkylation of nitriles with primary alcohols. a1,4-Dioxane was used as solvent, 24 ...
Figure 4: Manganese complexes used for alkylation of heterocyclic compounds.
Scheme 56: Aminomethylation of aromatic compounds with secondary amines and methanol catalyzed by Mn22.
Scheme 57: Regioselective alkylation of indolines with alcohols catalyzed by Mn9. aMn9 (4 mol %), 48 h.
Scheme 58: Proposed mechanism for the C- and N-alkylation of indolines with alcohols.
Scheme 59: C-Alkylation of methyl N-heteroarenes with primary alcohols catalyzed by Mn1. aTime was 60 h.
Scheme 60: C-Alkylation of oxindoles with secondary alcohols.
Scheme 61: Plausible mechanism for the Mn23-catalyzed C-alkylation of oxindoles with secondary alcohols.
Scheme 62: Synthesis of C-3-alkylated products by coupling alcohols with indoles and aminoalcohols.
Scheme 63: C3-Alkylation of indoles using Mn1.
Scheme 64: C-Methylation of indoles with Mn15 and methanol.
Scheme 65: α-Alkylation of 2-oxindoles with primary and secondary alcohols catalyzed by Mn25. aReaction carrie...
Scheme 66: Dehydrogenative alkylation of indolines with Mn1. aMn1 (5.0 mol %) was used.
Scheme 67: Synthesis of bis(indolyl)methane derivatives from indoles and alcohols catalyzed by Mn26. aMn26 (5....
Scheme 68: One-pot synthesis of pyrimidines via BH.
Scheme 69: Synthesis of pyrroles from alcohols and aminoalcohols using Mn4.
Scheme 70: Synthesis of pyrroles via multicomponent reaction catalyzed by Mn12.
Scheme 71: Friedländer quinoline synthesis using an in situ-generated phosphine-free manganese catalyst.
Scheme 72: Quinoline synthesis using bis-N-heterocyclic carbene-manganese catalyst Mn6.
Scheme 73: Quinoline synthesis using manganese(III)-porphyrin catalyst Mn7.
Scheme 74: Manganese-catalyzed tetrahydroquinoline synthesis via borrowing BH.
Scheme 75: Proposed mechanism for the manganese-catalyzed tetrahydroquinoline synthesis.
Scheme 76: Synthesis of C3-alkylated indoles using Mn24.
Scheme 77: Synthesis of C-3-alkylated indoles using Mn1.
Scheme 78: C–C Bond formation by coupling of alcohols and ylides.
Scheme 79: C-Alkylation of fluorene with alcohols catalyzed by Mn24.
Scheme 80: Proposed mechanism for the C-alkylation of fluorene with alcohols catalyzed by Mn24.
Scheme 81: α-Alkylation of sulfones using Mn-PNN catalyst Mn28.
A Diels–Alder probe for discovery of natural products containing furan moieties
- Alyssa S. Eggly,
- Namuunzul Otgontseren,
- Carson B. Roberts,
- Amir Y. Alwali,
- Haylie E. Hennigan and
- Elizabeth I. Parkinson
Beilstein J. Org. Chem. 2024, 20, 1001–1010, doi:10.3762/bjoc.20.88
- for 18 was more complicated, showing many more side products compared to other tested substrates (see Figure S7 in Supporting Information File 1). We hypothesize this is due to 18 undergoing a reaction in aqueous solutions to generate a geminal diol in place of an aldehyde, as has been previously
Graphical Abstract
Figure 1: A) Bioactive natural products containing a furan ring (blue) or 3-furoic acid moiety (red): plakors...
Figure 2: A) A diagram of an example of a molecular probe. B) The maleimide-based probe (6) for furans.
Figure 3: A) General Diels–Alder reaction scheme. B) MMF derivatives explored in this reaction.
Figure 4: A. Reaction scheme. B. Representative mass spectra of MMF5 cycloadduct 24 with 3:1 isotopic ratio p...
Figure 5: A. The UV trace (254 nm) for M145 control, M145 + probe 6, W75 control, and W75 + probe 6. M145 con...
Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas
- Alexander S. Hampton,
- David R. W. Hodgson,
- Graham McDougald,
- Linhua Wang and
- Graham Sandford
Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41
- 13C{1H} NMR spectra contained signals supporting the presence of ketone (e.g., δC = 185.6 ppm for 5a) and ester (δC = 161.9 ppm for 5a) functionalities. Difluoroketoester products were found to hydrate readily to give gem-diol derivatives during aqueous work-up [39], thus reducing the efficiency of
- extraction. Indeed, attempts to grow a single crystal of 5e from a mixture of EtOH and water led to the isolation of the corresponding gem-diol (Figure 3). There are very few examples of organic structures containing a C(OH)2–CF2–C fragment in the CCDC and only three acyclic examples (CSD 5.43 (Nov. 2021
Graphical Abstract
Scheme 1: Monofluorination of 1,3-diphenylpropane-1,3-dione with Selectfluor.
Scheme 2: Synthesis of 2,2-difluoro-1,3-diphenylpropane-1,3-dione (3a).
Figure 1: Molecular structure of 2,2-difluoro-1,3-diphenylpropane-1,3-dione (3a).
Figure 2: Crystal packing structure of 3f as determined by SXRC.
Figure 3: Molecular structure and crystal packing of 5e as determined by SXRC.
Scheme 3: Proposed mechanism of the quinuclidine-mediated difluorination of 1,3-dicarbonyl substrates.
Scheme 4: Proposed mechanisms of carbonate and chloride ion-mediated difluorination of 1,3-dicarbonyl substra...
Comparison of glycosyl donors: a supramer approach
- Anna V. Orlova,
- Nelly N. Malysheva,
- Maria V. Panova,
- Nikita M. Podvalnyy,
- Michael G. Medvedev and
- Leonid O. Kononov
Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18
- prepared from the known sialic acid derivative 5 [36] with an 8,9-O-isopropylidene group by a three-step reaction sequence (see Scheme 2). Exhaustive chloroacetylation of hydroxy groups in diol 5 with chloroacetic anhydride and 2,4,6-collidine in CH2Cl2 gave bis-chloroacetate 6 (90% yield), which was
- treated with 90% aq trifluoroacetic acid in CH2Cl2 to give diol 7 (70% yield) that was formed due to migration of a chloroacetyl group from O-7 to O-9. The structure of diol 7 was established by NMR spectroscopy, high-resolution mass spectrometry and X-ray diffraction analysis (see the Experimental
- section and Supporting Information File 1 for the details). Diol 7 was converted into glycosyl donor 2 by O-trifluoroacetylation with trifluoroacetic anhydride and sodium trifluoroacetate under previously developed [36][55] conditions. Supramer analysis As we know that the concentrations of reactants can
Graphical Abstract
Scheme 1: Model sialylation reaction. TFA = CF3CO; ClAc = ClCH2CO.
Scheme 2: Synthesis of sialyl donor 2.
Figure 1: Concentration dependence of the specific optical rotation ([α]D28 / deg·dm−1·cm3·g−1) of solutions ...
Figure 2: Comparison of the outcome of the sialylation of glycosyl acceptor 3 with sialyl donors 1 or 2 perfo...
Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis
- Bel Youssouf G. Mountessou,
- Élodie Gisèle M. Anoumedem,
- Blondelle M. Kemkuignou,
- Yasmina Marin-Felix,
- Frank Surup,
- Marc Stadler and
- Simeon F. Kouam
Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112
- × 50 mm, Phenomenex), and Nucleosil 120 OH Diol (7 µm, 250 × 21 mm, Machery-Nagel, Düren, Germany) columns maintained at room temperature. Normal phase p-HPLC equipped with DAD detector (Agilent 1100 Series, Santa Clara, USA) was connected to a Nucleosil 120 OH Diol column. Deionized water used for RP
- fractions from the three repeated runs were combined to give three sub-fractions (D1–D3). All these sub-fractions D1 (12 mg), D2 (8 mg), and D3 (15.8 mg) were further separately purified over normal phase preparative HPLC with a DAD detector with a Nucleosil 120 OH Diol column (7 µm, 250 × 21 mm) used as
- , tR = 11.21 min), and 7 (1.45 mg, yellow neat solid, tR = 15.00 min), 4 (2.45 mg, white amorphous powder, tR = 22.00 min), respectively. Successive purifications of series F (898 mg) over normal (CH2CH2/MeOH 92:8, Nucleosil 120 OH Diol column) and reversed-phase preparative HLPC (Gilson, PLC 2020
Graphical Abstract
Figure 1: Chemical structures of compounds 1 and 2.
Figure 2: Key COSY and HMBC correlations of compounds 1 and 2.
Synthesis of ether lipids: natural compounds and analogues
- Marco Antônio G. B. Gomes,
- Alicia Bauduin,
- Chloé Le Roux,
- Romain Fouinneteau,
- Wilfried Berthe,
- Mathieu Berchel,
- Hélène Couthon and
- Paul-Alain Jaffrès
Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96
- produces the diester 4.12 with an inversion of the configuration of the chiral carbon atom. Then, 4.12 was hydrolyzed in the presence of KOH to produce 4.10. The installation of the phosphocholine group was achieved following two schemes: a) Starting from the diol 4.10 (Figure 4C), tritylation and
- also achieved in the last step (Figure 5) [73]. DIBALH (diisobutylaluminium hydride) in toluene was added to hexadecanol in dichloromethane at 0 °C (Figure 5) to form in situ a lithium alcoholate. Then, S-glycidol was added at rt to produce in 50% yield the diol 5.2 after a regioselective opening of
- deprotection of diol with HCl, the aryl ether glycerol 10.3. The protection of the sn-2 position with a benzyl group was achieved by a classical tritylation of the primary alcohol, benzylation of the secondary alcohol and removing the trityl protecting group. The low yield of this three-step sequence is due to
Graphical Abstract
Figure 1: Chemical structure of some natural ether lipids (ELs).
Figure 2: Synthesis of lyso-PAF and PAF from 1-O-alkylglycerol [64].
Figure 3: Synthesis of lyso-PAF from 1,3-benzylideneglycerol 3.1 [69].
Figure 4: A) Synthesis of the two enantiomers of octadecylglycerol (4.6 and 4.10) from ᴅ-mannitol (4.1); B) s...
Figure 5: Four-step synthesis of PAF 5.6 from (S)-glycidol [73].
Figure 6: Synthesis of 1-O-alkylglycerol A) from solketal, B) from ᴅ- or ʟ-tartaric acid and the intermediate ...
Figure 7: Synthesis of EL building blocks starting from substituted glycidol 7.1a–c [82].
Figure 8: Synthesis of PAF 8.5 by using phosphoramidite 8.2 [86].
Figure 9: Synthesis of oleyl-PAF 9.7 from ʟ-serine [88].
Figure 10: Synthesis of racemic analogues of lyso-PAF 10.8 and PAF 10.9 featuring a phenyl group between the g...
Figure 11: Synthesis of racemic deoxy-lyso-PAF 11.7 and deoxy-PAF 11.8 [91].
Figure 12: Synthesis of racemic thio-PAF 12.8 [93].
Figure 13: Racemic synthesis of 13.6 to illustrate the modification of the glycerol backbone by adding a methy...
Figure 14: Racemic synthesis of 14.5 as an illustration of the introduction of methyl substituents on the glyc...
Figure 15: Synthesis of functionalized sn-2-acyl chains of PC-EL; A) Steglich esterification or acylation reac...
Figure 16: Synthesis of racemic mc-PAF (16.3), a carbamate analogue of PAF [102].
Figure 17: A) Synthesis of (R)-17.2 and (S)-17.6 starting from (S)-solketal (17.1); B) synthesis of N3-PAF (17...
Figure 18: Modification of the phosphocholine polar head to produce PAF analogues [81].
Figure 19: Racemic PAF analogues 19.3 and 19.5 characterized by the absence of the phosphate group [107].
Figure 20: Synthesis of PIP3-PAF (20.7) [108].
Figure 21: Large-scale synthesis of C18-edelfosine (21.8) [116].
Figure 22: Synthesis of C16-edelfosine (22.10) starting from isopropylidene-ʟ-glyceric acid methyl ester (22.1...
Figure 23: Phosphocholine moiety installation by the use of chlorophosphite 23.2 as key reagent [119].
Figure 24: Synthesis of rac-1-alkyl-2-O-methylglycerol (AMG) [120].
Figure 25: Synthesis of stereocontrolled 1-alkyl-2-O-methyl glycerol 25.9 (AMG) from dimethyl ᴅ-tartrate [81].
Figure 26: A) Racemic synthesis of thioether 26.4 [129,130], B) structure of sulfone analogue 26.5 [129].
Figure 27: Stereocontrolled synthesis of C18-edelfosine thioether analogue 27.8 [118].
Figure 28: Synthesis of thioether 28.4 that include a thiophosphate function [134].
Figure 29: Synthesis of ammonium thioether 29.4 and 29.6 [135].
Figure 30: Synthesis of the N-methylamino analogue of edelfosine 30.6 (BN52211) [138].
Figure 31: Synthesis of 1-desoxy analogues of edelfosine; A) with a saturated alkyl chain; B) synthesis of the...
Figure 32: Stereocontrolled synthesis of edelfosine analogue (S)-32.8 featuring a C18:1 lipid chain [142].
Figure 33: Synthesis of edelfosine analogues with modulation of the lipid chain; A) illustration with the synt...
Figure 34: Synthesis of phospholipid featuring a carbamate function to link the lipid chain to the glycerol un...
Figure 35: Synthesis of sesquiterpene conjugates of phospho glycero ether lipids [148].
Figure 36: Racemic synthesis of methyl-substituted glycerol analogues 36.7 and 36.10: A) synthesis of diether ...
Figure 37: Racemic synthesis of ilmofosine (37.6) [155,156].
Figure 38: A) Stereoselective synthesis of 38.5 via a stereoselective hydroboration reaction; B) synthesis of ...
Figure 39: Racemic synthesis of SRI62-834 (39.6) featuring a spiro-tetrahydrofurane heterocycle in position 2 ...
Figure 40: Racemic synthesis of edelfosine analogue 40.5 featuring an imidazole moiety in sn-2 position [160].
Figure 41: Racemic synthesis of fluorine-functionalized EL: A) Synthesis of 41.6 and B) synthesis of 41.8 [161-163].
Figure 42: A) Synthesis of the β-keto-ester 42.6 that also features a decyl linker between the phosphate and t...
Figure 43: Synthesis of phosphonate-based ether lipids; A) edelfosine phosphonate analogue 43.7 and B) thioeth...
Figure 44: Enantioselective synthesis of phosphonates 44.3 and 44.4 [171].
Figure 45: Racemic synthesis of phosphinate-based ether lipid 45.10 [172].
Figure 46: Racemic synthesis of edelfosine arsonium analogue 46.5 [173].
Figure 47: Synthesis of edelfosine dimethylammonium analogue 47.2 [118].
Figure 48: Synthesis of rac-C18-edelfosine methylammonium analogue 48.4 [176].
Figure 49: A) Synthesis of edelfosine N-methylpyrrolidinium analogue 49.2 or N-methylmorpholinium analogue 49.3...
Figure 50: A) Synthesis of edelfosine’s analogue 50.4 with a PE polar group; B) illustration of a pyridinium d...
Figure 51: A) Synthesis of 51.4 featuring a thiazolium cationic moiety; B) synthesis of thiazolium-based EL 51...
Figure 52: Synthesis of cationic ether lipids 52.3, 52.4 and 52.6 [135,183].
Figure 53: Synthesis of cationic carbamate ether lipid 53.5 [184].
Figure 54: Synthesis of cationic sulfonamide 54.5 [185].
Figure 55: Chemical structure of ONO-6240 (55.1) and SRI-63-119 (55.2).
Figure 56: Synthesis of non-ionic ether lipids 56.2–56.9 [188].
Figure 57: Synthesis of ether lipid conjugated to foscarnet 57.6 [189].
Figure 58: A) Synthesis of ether lipid conjugated to arabinofuranosylcytosine; B) synthesis of AZT conjugated ...
Figure 59: Synthesis of quercetin conjugate to edelfosine [191].
Figure 60: Synthesis of 60.8 (Glc-PAF) [194].
Figure 61: A) Synthesis of amino ether lipid 61.7 functionalized with a rhamnose unit and its amide analogue 6...
Figure 62: A) Synthesis of glucose ether lipid 62.4; B) structure of ether lipid 62.5 possessing a maltose uni...
Figure 63: A) Synthesis of glucuronic methyl ester 63.8; B) structure of cellobiose 63.9 and maltose 63.10 ana...
Figure 64: A) Synthesis of maltosyl glycerolipid 64.7; B) structure of lactose analogue 64.8 prepared followin...
Figure 65: A) Asymmetric synthesis of the aglycone moiety starting from allyl 4-methoxyphenyl ether; B) glycos...
Figure 66: A) Synthesis of ohmline possessing a lactose moiety. B) Structure of other glyco glycero lipids pre...
Figure 67: A) Synthesis of lactose-glycerol ether lipid 67.5; B) analogues possessing a maltose (67.6) or meli...
Figure 68: Synthesis of digalactosyl EL 68.6, A) by using trityl, benzyl and acetyl protecting groups, B) by u...
Figure 69: A) Synthesis of α-ohmline; B) structure of disaccharide ether lipids prepared by using similar meth...
Figure 70: Synthesis of lactose ether lipid 70.3 and its analogue 70.6 featuring a carbamate function as linke...
Figure 71: Synthesis of rhamnopyranoside diether 71.4 [196].
Figure 72: Synthesis of 1-O-hexadecyl-2-O-methyl-3-S-(α-ᴅ-1'-thioglucopyranosyl)-sn-glycerol (72.5) [225].
Figure 73: A) Preparation of lipid intermediate 73.4; B) synthesis of 2-desoxy-C-glycoside 73.10 [226].
Figure 74: Synthesis of galactose-pyridinium salt 74.3 [228].
Figure 75: Synthesis of myo-inositol derivative Ino-C2-PAF (75.10) [230].
Figure 76: A) Synthesis of myo-inositol phosphate building block 76.7; B) synthesis of myo-inositolphosphate d...
Figure 77: A) Synthesis of phosphatidyl-3-desoxy-inositol 77.4; B) synthesis of phosphono-3-desoxyinositol 77.9...
Figure 78: A) Structure of diether phosphatidyl-myo-inositol-3,4-diphosphate 78.1; B) synthesis of phosphatidy...
Figure 79: A) Synthesis of diether-phosphatidyl derivative 79.4 featuring a hydroxymethyl group in place of a ...
Figure 80: Synthesis of Glc-amine-PAF [78].
Figure 81: Synthesis of glucosamine ether lipid 81.4 and its analogues functionalized in position 3 of the ami...
Figure 82: Synthesis of fully deprotected aminoglucoside ether lipid 82.5 [246].
Figure 83: Synthesis of C-aminoglycoside 83.12 using Ramberg–Bäcklund rearrangement as a key step [250].
Figure 84: A) List of the most important glyco lipids and amino glyco lipids included in the study of Arthur a...
Figure 85: Synthesis of mannosamine ether lipid 85.6 [254].
Figure 86: A) Synthesis of glucosamine ether lipids with a non-natural ʟ-glucosamine moiety; B) synthesis of e...
Figure 87: A) Structure of the most efficient anticancer agents 87.1–87.4 featuring a diamino glyco ether lipi...
Figure 88: A) Synthesis of diamino glyco ether lipid 87.4; B) synthesis of bis-glycosylated ether lipid 88.10 [256]....
Figure 89: Synthesis of triamino ether lipid 89.4 [260].
Figure 90: Synthesis of chlorambucil conjugate 90.7 [261].
Figure 91: Three main methods for the preparation of glycerol ether lipid 91.3; A) from solketal and via a tri...
Figure 92: Four different methods for the installation of the phosphocholine polar head group; A) method using...
Figure 93: Illustration of two methods for the installation of saccharides or aminosaccharides; A) O-glycosyla...
Photoredox catalysis harvesting multiple photon or electrochemical energies
- Mattia Lepori,
- Simon Schmid and
- Joshua P. Barham
Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81
Graphical Abstract
Figure 1: Oxidative and reductive activations of organic compounds harvesting photoredox catalysis.
Figure 2: General catalytic cycles of radical ion conPET (left) and radical ion e-PRC (right).
Figure 3: “Beginner’s guide”: comparison between advantages, capacities, and prospectives of conPET and PEC.
Figure 4: A) conPET reductive dehalogenation of aryl halides with PDI. B) Reductive C–H arylation with pyrrol...
Figure 5: A) Chromoselective mono- and disubstitution or polybrominated pyrimidines with pyrroles. B) Sequent...
Figure 6: A) Synthesis of pyrrolo[1,2-a]quinolines. B) Synthesis of ullazines.
Figure 7: A) Reductive phosphorylation of aryl halides via conPET. B) Selected examples from the substrate sc...
Figure 8: A) Reductive dehalogenation of aryl halides via conPET and selected examples from the substrate sco...
Figure 9: A) Reductive C–H arylation of aryl halides via conPET (top) and selected examples from the substrat...
Figure 10: A) Reductive hydrodehalogenation of aryl halides with Mes-Acr-BF4. B) Selected examples from the su...
Figure 11: A) Reductive hydrodechlorination of aryl chlorides with 4-DPAIPN. B) Proposed formation of CO2•−. C...
Figure 12: A) Reductive conPET borylation with 3CzEPAIPN (top) and selected examples from the substrate scope ...
Figure 13: Scale-up of conPET phosphorylation with 3CzEPAIPN.
Figure 14: A) Borylation of 1d. B) Characteristics and structure of PC1 with green and red parts showing the l...
Figure 15: A) Reductive C–H arylation scope with polysulfide conPET (top) and selected examples from the subst...
Figure 16: Scale-up of A) C–H arylation and B) dehaloborylation with polysulfide photocatalysis in continuous-...
Figure 17: A) Formation of [Ir1]0 and [Ir2]0 upon PET between [Ir1]+ and Et3N. B) Mechanism of multi-photon ta...
Figure 18: A) Reductive hydrodehalogenation of aryl halides via multi-photon tandem photocatalysis. B) Selecte...
Figure 19: A) Carbonylative amidation of aryl halides in continuous flow. B) Selected examples from the substr...
Figure 20: A) General scheme for reductive (RQ) and oxidative quenching (OQ) protocols using [FeIII(btz)3](PF6)...
Figure 21: A) Carbonylative amidation of alkyl iodides with [IrIII(ppy)2(dtbbpy)]PF6. B) Selected examples fro...
Figure 22: A) Carboxylative C–N bond cleavage in cyclic amines. B) Selected examples from the substrate scope....
Figure 23: A) Formal reduction of alkenes to alkanes via transfer hydrogenation. B) Selected examples from the...
Figure 24: A) Birch-type reduction of benzenes with PMP-BPI. B) Selected examples from the substrate scope (sc...
Figure 25: Proposed mechanism of the OH− mediated conPET Birch-type reduction of benzene via generation of sol...
Figure 26: Reductive detosylation of N-tosylated amides with Mes-Acr-BF4. B) Selected examples from the substr...
Figure 27: A) Reductive detosylation of N-tosyl amides by dual PRC. B) Selected examples from the substrate sc...
Figure 28: A) Mechanism of the dual PRC based on PET between [Cu(dap)2]+ and DCA. B) Mechanism of the dual PRC...
Figure 29: A) N–O bond cleavage in Weinreb amides with anthracene. B) N–O bond cleavage in Weinreb amides rely...
Figure 30: A) Pentafluorosulfanylation and fluoride elimination. B) Mechanism of the pentafluorosulfanylation ...
Figure 31: A) α-Alkoxypentafluorosulfanylation (top) and selected examples from the substrate scope (bottom). ...
Figure 32: A) Oxidative amination of arenes with azoles catalyzed by N-Ph PTZ. B) Selected examples from the s...
Figure 33: A) C(sp3)–H bond activation by HAT via chloride oxidation by *N-Ph PTZ•+. B) Proposed mechanism for...
Figure 34: A) Recycling e-PRC C–H azolation of electron-rich arenes with pyrazoles using Mes-Acr+ as a photoca...
Figure 35: A) Radical ion e-PRC direct oxidation of unactivated arenes using TAC+ as an electro-activated phot...
Figure 36: A) Radical ion e-PRC direct oxidation of unactivated arenes using TPA as an electro-activated photo...
Figure 37: Proposed mechanism (top) and mode of preassembly (bottom).
Figure 38: A) Possible preassemblies of reactive (left) vs unreactive (right) arenes. B) Calculated spin densi...
Figure 39: A) Recycling e-PRC C(sp2 )–H acetoxylation of arenes using DDQ as a photocatalyst. B) Proposed cata...
Figure 40: Gram scale hydroxylation of benzene in a recirculated flow setup.
Figure 41: A) Radical ion e-PRC vicinal diamination of alkylarenes using TAC+ as an electro-activated photocat...
Figure 42: A) Sequential oxygenation of multiple adjacent C–H bonds under radical ion e-PRC using TAC+ as an e...
Figure 43: A) Enantioselective recycling e-PRC cyanation of benzylic C–H bonds using ADQS as photocatalyst. B)...
Figure 44: Proposed tandem mechanism by Xu and co-workers.
Figure 45: A) Enantioselective recycling e-PRC decarboxylative cyanation using Cu(acac)2, Ce(OTf)3 and a box l...
Figure 46: A) Enantioselective recycling e-PRC benzylic cyanation using Cu(MeCN)4BF4, box ligand and anthraqui...
Figure 47: A) Radical ion e-PRC acetoxyhydroxylation of aryl olefins using TAC+ as an electro-activated photoc...
Figure 48: Selected examples from the substrate scope.
Figure 49: Photoelectrochemical acetoxyhydroxylation in a recirculated flow setup.
Figure 50: A) Radical ion e-PRC aminooxygenation of aryl olefins using TAC+ as an electro-activated photocatal...
Figure 51: A) Recycling e-PRC C–H alkylation of heteroarenes with organic trifluoroborates using Mes-Acr+ as p...
Figure 52: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using CeCl3·7H2O as catalyst. B) ...
Figure 53: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using Fe(NH4)2(SO4)2·6H2O as cata...
Figure 54: A) Recycling e-PRC C–H alkylation of heteroarenes with alkyl oxalates and 4CzIPN as photocatalyst. ...
Figure 55: A) Recycling e-PRC decarboxylative C–H carbamoylation of heteroarenes using 4CzIPN as photocatalyst...
Figure 56: A) Photoelectrochemical HAT-mediated hydrocarbon activation via the chlorine radical. B) Proposed m...
Figure 57: A) Selected examples from the substrate scope. B) Gram and decagram scale semi-continuous flow PEC ...
Figure 58: A) Photoelectrochemical HAT-mediated dehydrogenative coupling of benzothiazoles with aliphatic C–H ...
Figure 59: A) Photoelectrochemical HAT activation of ethers using electro-activated TAC+ as photocatalyst. B) ...
Figure 60: Selected examples from the substrate scope.
Figure 61: A) Photoelectrochemical HAT-mediated synthesis of alkylated benzimidazo-fused isoquinolinones using...
Figure 62: A) Decoupled photoelectrochemical cerium-catalyzed oxydichlorination of alkynes using CeCl3 as cata...
Figure 63: Proposed decoupled photoelectrochemical mechanism.
Figure 64: A) Decoupled photoelectrochemical ring-opening bromination of tertiary cycloalkanols using MgBr2 as...
Figure 65: A) Recycling e-PRC ring-opening functionalization of cycloalkanols using CeCl3 as catalyst. B) Prop...
Figure 66: Selected examples from the substrate scope of the PEC ring-opening functionalization.
Figure 67: A) Radical ion e-PRC reduction of chloro- and bromoarenes using DCA as catalyst and various accepto...
Figure 68: A) Screening of different phthalimide derivatives as catalyst for the e-PRC reduction of aryl halid...
Figure 69: Screening of different organic catalysts for the e-PRC reduction of trialkylanilium salts.
Figure 70: A) e-PRC reduction of phosphonated phenols and anilinium salts. B) Selected examples from the subst...
Figure 71: A) ConPET and e-PRC reduction of 4-bromobenzonitrile using a naphthalene diimide (NDI) precatalyst ...
Figure 72: A) Radical ion e-PRC reduction of phosphinated aliphatic alcohols with n-BuO-NpMI as catalyst. B) C...
Figure 73: Selected examples from the substrate scope.
Figure 74: A) Recycling e-PRC reductive dimerization of benzylic chlorides using a [Cu2] catalyst. B) Proposed...
Figure 75: A) Decoupled photoelectrochemical C–H alkylation of heteroarenes through deamination of Katritzky s...
Figure 76: Proposed mechanism by Chen and co-workers.
Five new sesquiterpenoids from agarwood of Aquilaria sinensis
- Hong Zhou,
- Xu-Yang Li,
- Hong-Bin Fang,
- He-Zhong Jiang and
- Yong-Xian Cheng
Beilstein J. Org. Chem. 2023, 19, 998–1007, doi:10.3762/bjoc.19.75
- . The known compounds are readily identified as eudesm-4(15)-ene-7β,11-diol (6) [17], rel-(2R,8S,8aR)-2-(1,2,6,7,8,8a-hexahydro-8,8a-dimethyl-2-naphthyl)propan-2-ol (7) [18], γ-costol (8) [19], (+)-9-hydroxyselina-4,11-dien-14-oic acid (9) [20] and 1β-hydroxyeremophila-7(11),9-dien-8-one (10) [21] by
Graphical Abstract
Figure 1: Structures of compounds 1–10.
Figure 2: Key 1H,1H-COSY and HMBC correlations for 1–5.
Figure 3: Key ROESY correlations for 2–5.
Figure 4: The calculated and experimental ECD spectra of 1–5.
