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Search for "isocoumarins" in Full Text gives 10 result(s) in Beilstein Journal of Organic Chemistry.
Natural resorcylic lactones derived from alternariol
- Joachim Podlech
Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187
- were isolated together and all of them share a common name). Since it is intended to focus on naturally occurring alternariol-derived compounds, a number of somewhat related structures will not be discussed herein: Isocoumarins [20][21] and other structures, which are most likely not derived from
Graphical Abstract
Figure 1: Examples of compounds covered in this review categorized in six sub-classes (see text).
Figure 2: Examples of compounds not covered in this review.
Figure 3: Wrongly assigned and thus obsolete structures (details will be discussed in the respective chapters...
Figure 4: Alternariol with the correct IUPAC numbering and an occasionally used numbering based on the biphen...
Figure 5: Alternariol O-methyl ethers.
Figure 6: Alternariol O-glycosides.
Figure 7: Alternariol O-acetates and O-sulfates.
Figure 8: 2-Hydroxy- and 4-hydroxy-substituted alternariol and its O-methyl ethers.
Figure 9: Chloro- and amino-substituted alternariol and its O-methyl ethers.
Figure 10: Presumed alternariol derivatives with non-canonical substitution pattern.
Figure 11: Alternariol derivatives with the 1-methyl group hydroxylated.
Figure 12: Verrulactones: pseudo-dimeric derivatives of altertenuol and related compounds.
Figure 13: Biaryls formed by reductive lactone opening and/or by decarboxylation.
Figure 14: Altenuene and its diastereomers.
Figure 15: 9-O-Demethylated altenuene diastereomers.
Figure 16: Acetylated and methylated altenuene diastereomers.
Figure 17: Altenuene diastereomers modified with lactic acid, pyruvic acid, or acetone.
Figure 18: Neoaltenuene and related compounds.
Figure 19: Dehydroaltenusin and its derivatives.
Scheme 1: Equilibrium of dehydroaltenusin in polar solvents [278].
Figure 20: Further quinoid derivatives.
Figure 21: Dehydroaltenuenes.
Figure 22: Complex aggregates containing dehydroaltenuene substructures and related compounds.
Figure 23: Dihydroaltenuenes.
Figure 24: Altenuic acids and related compounds.
Figure 25: Cyclopentane- and cyclopentene-fused derivatives.
Figure 26: Cyclopentenone-fused derivatives.
Figure 27: Spiro-fused derivatives and a related ring-opened derivative.
Figure 28: Lactones-fused and lactone-substituted derivatives.
Scheme 2: Biosynthesis of alternariol [324].
Scheme 3: Biosynthesis of alternariol and its immediate successors with the genes involved in the respective ...
Scheme 4: Presumed formation of altenuene and its diastereomers and of botrallin.
Scheme 5: Presumed formation of altenuic acids and related compounds.
Scheme 6: A selection of plausible biosynthetic paths to cyclopenta-fused metabolites. (No stereochemistry is...
Scheme 7: Biomimetic synthesis of alternariol (1) by Harris and Hay [66].
Scheme 8: Total synthesis of alternariol (1) by Subba Rao et al. using a Diels–Alder approach [34].
Scheme 9: Total synthesis of alternariol (1) using a Suzuki strategy by Koch and Podlech [62], improved by Kim et...
Scheme 10: Total synthesis of alternariol (1) using an intramolecular biaryl coupling by Abe et al. [63].
Scheme 11: Total synthesis of altenuene (54) and isoaltenuene (55) by Podlech et al. [249].
Scheme 12: Total synthesis of neoaltenuene (69) by Podlech et al. [35].
Scheme 13: Total synthesis of TMC-264 (79) by Tatsuta et al. [185].
Scheme 14: Total synthesis of cephalosol (99) by Koert et al. [304].
Practical synthesis of isocoumarins via Rh(III)-catalyzed C–H activation/annulation cascade
- Qian-Ci Gao,
- Yi-Fei Li,
- Jun Xuan and
- Xiao-Qiang Hu
Beilstein J. Org. Chem. 2023, 19, 100–106, doi:10.3762/bjoc.19.10
- activation/annulation cascade of readily available enaminones with iodonium ylides towards the convenient synthesis of isocoumarins. This coupling system proceeds in useful chemical yields (up to 93%) via a cascade C–H activation, Rh-carbenoid migratory insertion and acid-promoted intramolecular annulation
- . The success of gram-scale reaction and diverse functionalization of isocoumarins demonstrated the synthetic utility of this protocol. Keywords: C–H activation; enaminone; iodonium ylide; isocoumarin; rhodium catalysis; Introduction Isocoumarins are an important structural motif in many naturally
- of 1,2-difunctionalized arenes with alkynes or carbon monoxide (Scheme 1b, III) [13][14][15][16], have been widely applied for the assembly of isocoumarins over the past decades. Recently, the transition-metal-catalyzed ortho C–H activation/annulation of benzoic acids has emerged as an attractive
Graphical Abstract
Scheme 1: Significance of isocoumarins (a), classic methods for the synthesis of isocoumarins (b) and reactio...
Scheme 2: Scope of enaminones.
Scheme 3: Scope of iodonium ylides.
Scheme 4: Gram-scale reaction (a) and synthetic transformation (b).
Scheme 5: Proposed mechanism.
Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds
- Sumana Mandal,
- Raju D. Chaudhari and
- Goutam Biswas
Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153
- heterocycles, namely benzofurans, benzothiophenes, isocoumarins, chromones, benzopyrans, 1,2-dihydronaphthaIenes, coumarins, and coumestan including some physiologically active heterocyclic natural products like flavones [84]. In the presence of Hg(OAc)2 in acetic acid, simple cyclization of ortho-substituted
Graphical Abstract
Scheme 1: Schematic representation of Hg(II)-mediated addition to an unsaturated bond.
Scheme 2: First report of Hg(II)-mediated synthesis of 2,5-dioxane derivatives from allyl alcohol.
Scheme 3: Stepwise synthesis of 2,6-distubstituted dioxane derivatives.
Scheme 4: Cyclization of carbohydrate alkene precursor.
Scheme 5: Hg(II)-mediated synthesis of C-glucopyranosyl derivatives.
Scheme 6: Synthesis of C-glycosyl amino acid derivative using Hg(TFA)2.
Scheme 7: Hg(OAc)2-mediated synthesis of α-ᴅ-ribose derivative.
Scheme 8: Synthesis of β-ᴅ-arabinose derivative 18.
Scheme 9: Hg(OAc)2-mediated synthesis of tetrahydrofuran derivatives.
Scheme 10: Synthesis of Hg(TFA)2-mediated bicyclic nucleoside derivative.
Scheme 11: Synthesis of pyrrolidine and piperidine derivatives.
Scheme 12: HgCl2-mediated synthesis of diastereomeric pyrrolidine derivatives.
Scheme 13: HgCl2-mediated cyclization of alkenyl α-aminophosphonates.
Scheme 14: Cyclization of 4-cycloocten-1-ol with Hg(OAc)2 forming fused bicyclic products.
Scheme 15: trans-Amino alcohol formation through Hg(II)-salt-mediated cyclization.
Scheme 16: Hg(OAc)2-mediated 2-aza- or 2-oxa-bicyclic ring formations.
Scheme 17: Hg(II)-salt-induced cyclic peroxide formation.
Scheme 18: Hg(OAc)2-mediated formation of 1,2,4-trioxanes.
Scheme 19: Endocyclic enol ether derivative formation through Hg(II) salts.
Scheme 20: Synthesis of optically active cyclic alanine derivatives.
Scheme 21: Hg(II)-salt-mediated formation of tetrahydropyrimidin-4(1H)-one derivatives.
Scheme 22: Cyclization of ether derivatives to form stereoselective oxazolidine derivatives.
Scheme 23: Cyclization of amide derivatives induced by Hg(OAc)2.
Scheme 24: Hg(OAc)2/Hg(TFA)2-promoted cyclization of salicylamide-derived amidal auxiliary derivatives.
Scheme 25: Hg(II)-salt-mediated cyclization to form dihydrobenzopyrans.
Scheme 26: HgCl2-induced cyclization of acetylenic silyl enol ether derivatives.
Scheme 27: Synthesis of exocyclic and endocyclic enol ether derivatives.
Scheme 28: Cyclization of trans-acetylenic alcohol by treatment with HgCl2.
Scheme 29: Synthesis of benzofuran derivatives in presence of HgCl2.
Scheme 30: a) Hg(II)-salt-mediated cyclization of 4-hydroxy-2-alkyn-1-ones to furan derivatives and b) its mec...
Scheme 31: Cyclization of arylacetylenes to synthesize carbocyclic and heterocyclic derivatives.
Scheme 32: Hg(II)-salt-promoted cyclization–rearrangement to form heterocyclic compounds.
Scheme 33: a) HgCl2-mediated cyclization reaction of tethered alkyne dithioacetals; and b) proposed mechanism.
Scheme 34: Cyclization of aryl allenic ethers on treatment with Hg(OTf)2.
Scheme 35: Hg(TFA)2-mediated cyclization of allene.
Scheme 36: Hg(II)-catalyzed intramolecular trans-etherification reaction of 2-hydroxy-1-(γ-methoxyallyl)tetrah...
Scheme 37: a) Cyclization of alkene derivatives by catalytic Hg(OTf)2 salts and b) mechanism of cyclization.
Scheme 38: a) Synthesis of 1,4-dihydroquinoline derivatives by Hg(OTf)2 and b) plausible mechanism of formatio...
Scheme 39: Synthesis of Hg(II)-salt-catalyzed heteroaromatic derivatives.
Scheme 40: Hg(II)-salt-catalyzed synthesis of dihydropyranone derivatives.
Scheme 41: Hg(II)-salt-catalyzed cyclization of alkynoic acids.
Scheme 42: Hg(II)-salt-mediated cyclization of alkyne carboxylic acids and alcohol to furan, pyran, and spiroc...
Scheme 43: Hg(II)-salt-mediated cyclization of 1,4-dihydroxy-5-alkyne derivatives.
Scheme 44: Six-membered morpholine derivative formation by catalytic Hg(II)-salt-induced cyclization.
Scheme 45: Hg(OTf)2-catalyzed hydroxylative carbocyclization of 1,6-enyne.
Scheme 46: a) Hg(OTf)2-catalyzed hydroxylative carbocyclization of 1,6-enyne. b) Proposed mechanism.
Scheme 47: a) Synthesis of carbocyclic derivatives using a catalytic amount of Hg(II) salt. b) Proposed mechan...
Scheme 48: Cyclization of 1-alkyn-5-ones to 2-methylfuran derivatives.
Scheme 49: Hg(NO3)2-catalyzed synthesis of 2-methylenepiperidine.
Scheme 50: a) Preparation of indole derivatives through cycloisomerization of 2-ethynylaniline and b) its mech...
Scheme 51: a) Hg(OTf)2-catalyzed synthesis of 3-indolinones and 3-coumaranones and b) simplified mechanism.
Scheme 52: a) Hg(OTf)2-catalyzed one pot cyclization of nitroalkyne and b) its plausible mechanism.
Scheme 53: Synthesis of tricyclic heterocyclic scaffolds.
Scheme 54: HgCl2-mediated cyclization of 2-alkynylphenyl alkyl sulfoxide.
Scheme 55: a) Hg(OTf)2-catalyzed cyclization of allenes and alkynes. b) Proposed mechanism of cyclization.
Scheme 56: Stereoselective synthesis of tetrahydropyran derivatives.
Scheme 57: a) Hg(ClO4)2-catalyzed cyclization of α-allenol derivatives. b) Simplified mechanism.
Scheme 58: Hg(TFA)2-promoted cyclization of a γ-hydroxy alkene derivative.
Scheme 59: Synthesis Hg(II)-salt-mediated cyclization of allyl alcohol for the construction of ventiloquinone ...
Scheme 60: Hg(OAc)2-mediated cyclization as a key step for the synthesis of hongconin.
Scheme 61: Examples of Hg(II)-salt-mediated cyclized ring formation in the syntheses of (±)-fastigilin C and (...
Scheme 62: Formal synthesis of (±)-thallusin.
Scheme 63: Total synthesis of hippuristanol and its analog.
Scheme 64: Total synthesis of solanoeclepin A.
Scheme 65: a) Synthesis of Hg(OTf)2-catalyzed azaspiro structure for the formation of natural products. b) Pro...
Synthesis of 1-indanones with a broad range of biological activity
- Marika Turek,
- Dorota Szczęsna,
- Marek Koprowski and
- Piotr Bałczewski
Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48
- the synthesis of kinamycin 9 derivatives, which exhibited a strong cytotoxic and anticancer activity (Scheme 4) [15]. Propionic acid derivatives are also useful substrates in syntheses of 1-indanones and isocoumarins [16]. These latter are essential reagents for the synthesis of bioactive compounds
Graphical Abstract
Figure 1: Biologically active 1-indanones and their structural analogues.
Figure 2: Number of papers about (a) 1-indanones, (b) synthesis of 1-indanones.
Scheme 1: Synthesis of 1-indanone (2) from hydrocinnamic acid (1).
Scheme 2: Synthesis of 1-indanone (2) from 3-(2-bromophenyl)propionic acid (3).
Scheme 3: Synthesis of 1-indanones 5 from 3-arylpropionic acids 4.
Scheme 4: Synthesis of kinamycin (9a) and methylkinamycin C (9b).
Scheme 5: Synthesis of trifluoromethyl-substituted arylpropionic acids 12, 1-indanones 13 and dihydrocoumarin...
Scheme 6: Synthesis of 1-indanones 16 from benzoic acids 15.
Scheme 7: Synthesis of 1-indanones 18 from arylpropionic and 3-arylacrylic acids 17.
Scheme 8: The NbCl5-induced one-step synthesis of 1-indanones 22.
Scheme 9: Synthesis of biologically active 1-indanone derivatives 26.
Scheme 10: Synthesis of enantiomerically pure indatraline ((−)-29).
Scheme 11: Synthesis of 1-indanone (2) from the acyl chloride 30.
Scheme 12: Synthesis of the mechanism-based inhibitors 33 of coelenterazine.
Scheme 13: Synthesis of the indane 2-imidazole derivative 37.
Scheme 14: Synthesis of fluorinated PAHs 41.
Scheme 15: Synthesis of 1-indanones 43 via transition metal complexes-catalyzed carbonylative cyclization of m...
Scheme 16: Synthesis of 6-methyl-1-indanone (46).
Scheme 17: Synthesis of 1-indanone (2) from ester 48.
Scheme 18: Synthesis of benzopyronaphthoquinone 51 from the spiro-1-indanone 50.
Scheme 19: Synthesis of the selective endothelin A receptor antagonist 55.
Scheme 20: Synthesis of 1-indanones 60 from methyl vinyl ketone (57).
Scheme 21: Synthesis of 1-indanones 64 from diethyl phthalate 61.
Scheme 22: Synthesis of 1-indanone derivatives 66 from various Meldrum’s acids 65.
Scheme 23: Synthesis of halo 1-indanones 69.
Scheme 24: Synthesis of substituted 1-indanones 71.
Scheme 25: Synthesis of spiro- and fused 1-indanones 73 and 74.
Scheme 26: Synthesis of spiro-1,3-indanodiones 77.
Scheme 27: Mechanistic pathway for the NHC-catalyzed Stetter–Aldol–Michael reaction.
Scheme 28: Synthesis of 2-benzylidene-1-indanone derivatives 88a–d.
Scheme 29: Synthesis of 1-indanone derivatives 90a–i.
Scheme 30: Synthesis of 1-indanones 96 from o-bromobenzaldehydes 93 and alkynes 94.
Scheme 31: Synthesis of 3-hydroxy-1-indanones 99.
Scheme 32: Photochemical preparation of 1-indanones 103 from ketones 100.
Scheme 33: Synthesis of chiral 3-aryl-1-indanones 107.
Scheme 34: Photochemical isomerization of 2-methylbenzil 108.
Scheme 35: Synthesis of 2-hydroxy-1-indanones 111a–c.
Scheme 36: Synthesis of 1-indanone derivatives 113 and 114 from η6-1,2-dioxobenzocyclobutene complex 112.
Scheme 37: Synthesis of nakiterpiosin (117).
Scheme 38: Synthesis of 2-alkyl-1-indanones 120.
Scheme 39: Synthesis of fluorine-containing 1-indanone derivatives 123.
Scheme 40: Synthesis of 2-benzylidene and 2-benzyl-1-indanones 126, 127 from the chalcone 124.
Scheme 41: Synthesis of 2-bromo-6-methoxy-3-phenyl-1-indanone (130).
Scheme 42: Synthesis of combretastatin A-4-like indanones 132a–s.
Figure 3: Chemical structures of investigated dienones 133 and synthesized cyclic products 134–137.
Figure 4: Chemical structures of 1-indanones and their heteroatom analogues 138–142.
Scheme 43: Synthesis of 2-phosphorylated and 2-non-phosphorylated 1-indanones 147 and 148 from β-ketophosphona...
Scheme 44: Photochemical synthesis of 1-indanone derivatives 150, 153a, 153b.
Scheme 45: Synthesis of polysubstituted-1-indanones 155, 157.
Scheme 46: Synthesis of 1-indanones 159a–g from α-arylpropargyl alcohols 158 using RhCl(PPh3)3 as a catalyst.
Scheme 47: Synthesis of optically active 1-indanones 162 via the asymmetric Rh-catalyzed isomerization of race...
Scheme 48: Mechanism of the Rh-catalyzed isomerization of α-arylpropargyl alcohols 161 to 1-indanones 162.
Figure 5: Chemical structure of abicoviromycin (168) and its new benzo derivative 169.
Scheme 49: Synthesis of racemic benzoabicoviromycin 172.
Scheme 50: Synthesis of [14C]indene 176.
Scheme 51: Synthesis of indanone derivatives 178–180.
Scheme 52: Synthesis of racemic pterosin A 186.
Scheme 53: Synthesis of trans-2,3-disubstituted 1-indanones 189.
Scheme 54: Synthesis of 3-aryl-1-indanone derivatives 192.
Scheme 55: Synthesis of 1-indanone derivatives 194 from 3-(2-iodoaryl)propanonitriles 193.
Scheme 56: Synthesis of 1-indanones 200–204 by cyclization of aromatic nitriles.
Scheme 57: Synthesis of 1,1’-spirobi[indan-3,3’-dione] derivative 208.
Scheme 58: Total synthesis of atipamezole analogues 211.
Scheme 59: Synthesis of 3-[4-(1-piperidinoethoxy)phenyl]spiro[indene-1,1’-indan]-5,5’-diol hydrochloride 216.
Scheme 60: Synthesis of 3-arylindan-1-ones 219.
Scheme 61: Synthesis of 2-hydroxy-1-indanones 222.
Scheme 62: Synthesis of the 1-indanone 224 from the THP/MOM protected chalcone epoxide 223.
Scheme 63: Synthesis of 1-indanones 227 from γ,δ-epoxy ketones 226.
Scheme 64: Synthesis of 2-hydroxy-2-methylindanone (230).
Scheme 65: Synthesis of 1-indanone derivatives 234 from cyclopropanol derivatives 233.
Scheme 66: Synthesis of substituted 1-indanone derivatives 237.
Scheme 67: Synthesis of 7-methyl substituted 1-indanone 241 from 1,3-pentadiene (238) and 2-cyclopentenone (239...
Scheme 68: Synthesis of disubstituted 1-indanone 246 from the siloxydiene 244 and 2-cyclopentenone 239.
Scheme 69: Synthesis of 5-hydroxy-1-indanone (250) via the Diels–Alder reaction of 1,3-diene 248 with sulfoxid...
Scheme 70: Synthesis of halogenated 1-indanones 253a and 253b.
Scheme 71: Synthesis of 1-indanones 257 and 258 from 2-bromocyclopentenones 254.
Scheme 72: Synthesis of 1-indanone 261 from 2-bromo-4-acetoxy-2-cyclopenten-1-one (260) and 1,2-dihydro-4-viny...
Scheme 73: Synthesis of 1-indanone 265 from 1,2-dihydro-7-methoxy-4-vinylnaphthalene (262) and bromo-substitut...
Scheme 74: Synthesis of 1-indanone 268 from dihydro-3-vinylphenanthrene 266 and 4-acetoxy-2-cyclopenten-1-one (...
Scheme 75: Synthesis of 1-indanone 271 from phenylselenyl-substituted cyclopentenone 268.
Scheme 76: Synthesis of 1-indanone 272 from the trienone 270.
Scheme 77: Synthesis of the 1-indanone 276 from the aldehyde 273.
Scheme 78: Synthesis of 1-indanones 278 and 279.
Scheme 79: Synthesis of 1-indanone 285 from octa-1,7-diyne (282) and cyclopentenone 239.
Scheme 80: Synthesis of benz[f]indan-1-one (287) from cyclopentenone 239 and o-bis(dibromomethyl)benzene (286)....
Scheme 81: Synthesis of 3-methyl-substituted benz[f]indan-1-one 291 from o-bis(dibromomethyl)benzene (286) and...
Scheme 82: Synthesis of benz[f]indan-1-one (295) from the anthracene epidioxide 292.
Scheme 83: Synthesis of 1-indanone 299 from homophthalic anhydride 298 and cyclopentynone 297.
Scheme 84: Synthesis of cyano-substituted 1-indanone derivative 301 from 2-cyanomethylbenzaldehyde (300) and c...
Scheme 85: Synthesis of 1-indanone derivatives 303–305 from ketene dithioacetals 302.
Scheme 86: Synthesis of 1-indanones 309–316.
Scheme 87: Mechanism of the hexadehydro-Diels–Alder (HDDA) reaction.
Scheme 88: Synthesis of 1-indenone 318 and 1-indanones 320 and 321 from tetraynes 317 and 319.
Scheme 89: Synthesis of 1-indanone 320 from the triyn 319.
Scheme 90: Synthesis 1-indanone 328 from 2-methylfuran 324.
Scheme 91: Synthesis of 1-indanones 330 and 331 from furans 329.
Scheme 92: Synthesis of 1-indanone 333 from the cycloadduct 332.
Scheme 93: Synthesis of (S)-3-arylindan-1-ones 335.
Scheme 94: Synthesis of (R)-2-acetoxy-1-indanone 338.
Figure 6: Chemical structures of obtained cyclopenta[α]phenanthrenes 339.
Scheme 95: Synthesis of the benzoindanone 343 from arylacetaldehyde 340 with 1-trimethylsilyloxycyclopentene (...
New furoisocoumarins and isocoumarins from the mangrove endophytic fungus Aspergillus sp. 085242
- Ze’en Xiao,
- Senhua Chen,
- Runlin Cai,
- Shao’e Lin,
- Kui Hong and
- Zhigang She
Beilstein J. Org. Chem. 2016, 12, 2077–2085, doi:10.3762/bjoc.12.196
- sp. 085242 afforded eight isocoumarin derivatives 1–8 and one isoquinoline 9. Asperisocoumarins A and B (1 and 2) were new furoisocoumarins, and asperisocoumarins E and F (5 and 6) were new isocoumarins. Their structures were established by analysis of their spectroscopic data and the absolute
- configuration of compound 2 was unambiguously determined by X-ray structure analysis and ECD calculation. Moreover, the absolute configurations of compounds 3–5 were assigned by comparison of their ECD spectra with isocoumarins described in the literature. Asperisocoumarins C and D (3 and 4) were fully
- characterized spectroscopically and isolated from a natural source for the first time. Asperisocoumarins A–D (1–4) related to the class of furo[3,2-h]isocoumarins are rarely occurring in natural sources. Compounds 2, 5, and 6 showed moderate α-glucosidase inhibitory activity with IC50 of 87.8, 52.3, and 95.6 μM
Graphical Abstract
Figure 1: The structure of compounds 1–9.
Figure 2: Key HMBC (arrows) and COSY (bold lines) correlations of compounds 1−6.
Figure 3: ORTEP structure of compound 2.
Figure 4: Comparison of the experimental and calculated ECD spectra of 2.
Figure 5: The experimental ECD spectra of 2–5.
Figure 6: ORTEP structures of compound 7 and 8.
Organophosphorus chemistry
- Paul R. Hanson
Beilstein J. Org. Chem. 2014, 10, 2087–2088, doi:10.3762/bjoc.10.217
- phosphinoyl-indoles and phosphinoyl-isocoumarins and new chemistries of H-phosphonates. The Thematic Series also details work on new metathesis-based reactions of vinyl phosphonates and phosphate tethers, novel phosphorus-based ligands in asymmetric catalysis, novel rasta resin–triphenylphosphine oxides and
Allenylphosphine oxides as simple scaffolds for phosphinoylindoles and phosphinoylisocoumarins
- G. Gangadhararao,
- Ramesh Kotikalapudi,
- M. Nagarjuna Reddy and
- K. C. Kumara Swamy
Beilstein J. Org. Chem. 2014, 10, 996–1005, doi:10.3762/bjoc.10.99
- . Interestingly, in the presence of wet trifluoroacetic acid, in addition to phosphinoylisocoumarins, phosphorus-free isocoumarins were also obtained. Key products were characterized by single crystal X-ray crystallography. Keywords: allenes; indoles; isocoumarins; organophosphorus; phosphinoyl-heterocycles
- deprotection of an allene intermediate under Lewis acid mediation [22]. In this context it was of interest to see, in a reaction like that shown in Scheme 1c, whether the introduction of an amide or a carboxylate ester in place of the –CHO group could lead to phosphinoyl-subtstituted indoles/isocoumarins via
- allenic intermediates or not. It is pertinent to note that indoles and isocoumarins are core structures found in many natural and pharmacological products [32][33][34]. Thus in this paper, we wish to report simple synthetic routes to phosphinoylindoles, and -isocoumarins utilizing functionalized
Graphical Abstract
Scheme 1: Reaction of P(III)-Cl precursors with propargyl alcohols leading to phosphorus based (a) N-hydroxyi...
Figure 1: Functionalized propargyl alcohols 1a–m and 2a–j used in the present study.
Scheme 2: Synthesis of functionalized allenes 3a–c, 3m and 4a–j.
Scheme 3: Reaction of functionalized allenes 3a and 3m leading to phosphinoylindoles. Conditions: (i) K3PO4 (...
Figure 2: Molecular structure of compound 7. Hydrogen atoms (except PCH) are omitted for clarity. Selected bo...
Figure 3: Molecular structure of compound 9. Hydrogen atoms (except NH) are omitted for clarity. Selected bon...
Scheme 4: Synthesis of phosphinoylindole from allene 3a in a single step.
Scheme 5: One-pot preparation of substituted phosphinoylindoles 6 and 9–19 from functionalized alcohols.
Scheme 6: Possible pathway for the formation of phosphinoyl indoles 6 and 9–19.
Scheme 7: Synthesis of phosphinoylisocoumarins from functionalized allenes.
Figure 4: Molecular structure of 20. Selected bond lengths [Å] with estimated standard deviations are given i...
Scheme 8: Possible pathway for the formation of phosphinoylisocoumarins.
Scheme 9: Reaction of allenes in wet trifluoroacetic acid.
Figure 5: Molecular structure of 33. Selected bond lengths [Å] with estimated standard deviations are given i...
Scheme 10: Possible pathway for the formation of isocoumarins 30–35 (along with 21–23 and 27–29).
Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions
- Sudipta Pathak,
- Kamalesh Debnath and
- Animesh Pramanik
Beilstein J. Org. Chem. 2013, 9, 2344–2353, doi:10.3762/bjoc.9.269
- pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA) as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused
- isocoumarins were formed in good yields. This synthetic method has several advantages such as the employment of solvent-free reaction conditions without the use of any toxic reagents and metal catalysts, the ease of product isolation, the use of a recyclable catalyst, the low cost, the easy availability of the
- starting materials, and the excellent yields of products. Keywords: green chemistry; pyrrole-fused isocoumarin; reusable solid support; silica sulfuric acid; solvent-free condition; Introduction Isocoumarins are an important class of naturally occurring lactones [1][2][3], which has attracted the
Graphical Abstract
Scheme 1: Synthesis of pyrrole-fused isocoumarins.
Scheme 2: Reaction scheme for the synthesis of pyrrole-fused isocoumarins.
Figure 1: ORTEP diagram of 8c with atom numbering scheme. Thermal ellipsoids are shown at 50% probability wit...
Scheme 3: Mechanism of formation of isocoumarins 5 or 8 on the surface of SSA.
Figure 2: Reusability of SSA for the synthesis of pyrrole-fused isocoumarins.
Recent advances in the gold-catalyzed additions to C–C multiple bonds
- He Huang,
- Yu Zhou and
- Hong Liu
Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103
- for the preparation of substituted butenolides 101 and isocoumarins [51]. In this study, the authors employed a carbophilic Lewis acidic Au(I) catalyst to catalyze the cross-coupling reactivity of a second Lewis basic Pd catalyst in order to functionalize vinyl–gold intermediates arising from
Graphical Abstract
Scheme 1: Gold-catalyzed addition of alcohols.
Scheme 2: Gold-catalyzed cycloaddition of alcohols.
Scheme 3: Ionic liquids as the solvent in gold-catalyzed cycloaddition.
Scheme 4: Gold-catalyzed cycloaddition of diynes.
Scheme 5: Gold(I) chloride catalyzed cycloisomerization of 2-alkynyl-1,5-diols.
Scheme 6: Gold-catalyzed cycloaddition of glycols and dihydroxy compounds.
Scheme 7: Gold-catalyzed ring-opening of cyclopropenes.
Scheme 8: Gold-catalyzed intermolecular hydroalkoxylation of alkynes. PR3 = 41–45.
Scheme 9: Gold-catalyzed intramolecular 6-endo-dig cyclization of β-hydroxy-α,α-difluoroynones.
Scheme 10: Gold-catalyzed intermolecular hydroalkoxylation of non-activated olefins.
Scheme 11: Preparation of unsymmetrical ethers from alcohols.
Scheme 12: Expedient synthesis of dihydrofuran-3-ones.
Scheme 13: Catalytic approach to functionalized divinyl ketones.
Scheme 14: Gold-catalyzed glycosylation.
Scheme 15: Gold-catalyzed cycloaddition of aldehydes and ketones.
Scheme 16: Gold-catalyzed annulations of 2-(ynol)aryl aldehydes and o-alkynyl benzaldehydes.
Scheme 17: Gold-catalyzed addition of carboxylates.
Scheme 18: Dual-catalyzed rearrangement reaction of allenoates.
Scheme 19: Meyer–Schuster rearrangement of propargylic alcohols.
Scheme 20: Propargylic alcohol rearrangements.
Scheme 21: Gold-catalyzed synthesis of imines and amine alkylation.
Scheme 22: Hydroamination of allenes and allenamides.
Scheme 23: Gold-catalyzed inter- and intramolecular amination of alkynes and alkenes.
Scheme 24: Gold-catalyzed cycloisomerization of O-propioloyl oximes and β-allenylhydrazones.
Scheme 25: Intra- and intermolecular amination with ureas.
Scheme 26: Gold-catalyzed cyclization of ortho-alkynyl-N-sulfonylanilines and but-3-yn-1-amines.
Scheme 27: Gold-catalyzed piperidine ring synthesis.
Scheme 28: Ring expansion of alkylnyl cyclopropanes.
Scheme 29: Gold-catalyzed annulations of N-propargyl-β-enaminones and azomethine imines.
Scheme 30: Gold(I)-catalyzed cycloisomerization of aziridines.
Scheme 31: AuCl3/AgSbF6-catalyzed intramolecular amination of 2-(tosylamino)phenylprop-1-en-3-ols.
Scheme 32: Gold-catalyzed cyclization via a 7-endo-dig pathway.
Scheme 33: Gold-catalyzed synthesis of fused xanthines.
Scheme 34: Gold-catalyzed synthesis of amides and isoquinolines.
Scheme 35: Gold-catalyzed oxidative cross-coupling reactions of propargylic acetates.
Scheme 36: Gold-catalyzed nucleophilic addition to allenamides.
Scheme 37: Gold-catalyzed direct carbon–carbon bond coupling reactions.
Scheme 38: Gold-catalyzed C−H functionalization of indole/pyrrole heterocycles and non-activated arenes.
Scheme 39: Gold-catalyzed cycloisomerization of cyclic compounds.
Scheme 40: Gold-catalyzed cycloaddition of 1-aryl-1-allen-6-enes and propargyl acetates.
Scheme 41: Gold(I)-catalyzed cycloaddition with ligand-controlled regiochemistry.
Scheme 42: Gold(I)-catalyzed cycloaddition of dienes and enynes.
Scheme 43: Gold-catalyzed intramolecular cycloaddition of 3-alkoxy-1,5-enynes and 2,2-dipropargylmalonates.
Scheme 44: Gold-catalyzed intramolecular cycloaddition of 1,5-allenynes.
Scheme 45: Gold(I)-catalyzed cycloaddition of indoles.
Scheme 46: Gold-catalyzed annulation reactions.
Scheme 47: Gold–carbenoid induced cleavage of a sp3-hybridized C−H bond.
Scheme 48: Furan- and indole-based cascade reactions.
Scheme 49: Tandem process using aromatic alkynes.
Scheme 50: Gold-catalyzed cycloaddition of 1,3-dien-5-ynes.
Scheme 51: Gold-catalyzed cascade cyclization of diynes, propargylic esters, and 1,3-enynyl ketones.
Scheme 52: Tandem reaction of β-phenoxyimino ketones and alkynyl oxime ethers.
Scheme 53: Gold-catalyzed tandem cyclization of enynes, 2-(tosylamino)phenylprop-1-yn-3-ols, and allenoates.
Scheme 54: Cyclization of 2,4-dien-6-yne carboxylic acids.
Scheme 55: Gold(I)-catalyzed tandem cyclization approach to tetracyclic indolines.
Scheme 56: Gold-catalyzed tandem reactions of alkynes.
Scheme 57: Aminoarylation and oxyarylation of alkenes.
Scheme 58: Cycloaddition of 2-ethynylnitrobenzene with various alkenes.
Scheme 59: Gold-catalyzed tandem reactions of allenoates and alkynes.
Scheme 60: Gold-catalyzed asymmetric synthesis of 2,3-dihydropyrroles.
Scheme 61: Chiral [NHC–Au(I)]-catalyzed cyclization of enyne.
Scheme 62: Gold-catalyzed hydroaminations and hydroalkoxylations.
Scheme 63: Gold(I)-catalyzed asymmetric hydroalkoxylation of 1,3-dihydroxymethyl-2-alkynylbenzene chromium com...
Scheme 64: Gold-catalyzed synthesis of julolidine derivatives.
Scheme 65: Gold-catalyzed the synthesis of chiral fused heterocycles.
Scheme 66: Gold-catalyzed asymmetric reactions with 3,5-(t-Bu)2-4-MeO-MeOBIPHEP.
Scheme 67: Gold-catalyzed cyclization of o-(alkynyl) styrenes.
Scheme 68: Asymmetric gold(I)-catalyzed redox-neutral domino reactions of enynes.
Scheme 69: Gold(I)-catalyzed enantioselective polyene cyclization reaction.
Scheme 70: Gold(I)-catalyzed enantioselective synthesis of benzopyrans.
Scheme 71: Gold(I)-catalyzed enantioselective ring expansion of allenylcyclopropanols.
Pd/C-mediated synthesis of α-pyrone fused with a five-membered nitrogen heteroaryl ring: A new route to pyrano[4,3-c]pyrazol-4(1H)-ones
- Dhilli Rao Gorja,
- Venkateswara Rao Batchu,
- Ashok Ettam and
- Manojit Pal
Beilstein J. Org. Chem. 2009, 5, No. 64, doi:10.3762/bjoc.5.64
- ] (or 2H-pyran-2-one) and their benzo derivatives, e.g. isocoumarins [3], have shown a wide range of pharmacological activities [4][5][6] such as antifungal, antimicrobial, phytotoxic and other effects. On the other hand α-pyrones fused with a five-membered heteroaryl ring, e.g. thienopyranones, have
- category. It involves the reaction of methyl 2-cyano-3,3-dimethylthioacrylate with 1-tetralone and subsequently with hydrazine [8]. Though a number of methods are known for the synthesis of isocoumarins by constructing the pyrone ring [9][10][11][12][13][14][15][16][17] (the second strategy) none has been
- a carboxylate or an equivalent group in proximity to the triple bond). Thus, isocoumarins have been prepared by reacting o-iodobenzoic acid with terminal alkynes in the presence of a Pd-catalyst [14][15][16]. Recently, we have reported synthesis of thienopyranones following a similar strategy [7][18
Graphical Abstract
Figure 1: Polycyclic azaheteroaromatics (A) and pyrano[4,3-c]pyrazol-4(1H)-ones (B).
Scheme 1: Pd/C-mediated synthesis of 6-substituted pyrano[4,3-c]pyrazol-4(1H)-ones 3.
Scheme 2: Preparation of 5-iodo-1-methyl-1H-pyrazole-4-carboxylic acid (1).
Scheme 3: Mechanism of ring closure of intermediate alkyne Z.
