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Search for "phosphite" in Full Text gives 114 result(s) in Beilstein Journal of Organic Chemistry.
Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination
Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43
- this also with L = (t-Bu)2P(o-biphenyl). When the more reactive urea alkene 1a is examined, the reaction with 4a is efficient enough that reaction completion occurs prior to noticeable decomposition. In contrast, when a LAuNTf2 catalyst was prepared where L = tris(2,4-di-tert-butylphenyl)phosphite (6b
Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target
Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22
- ]. The ratio of α/β-anomers in compound 5 was found to be influenced by the reaction conditions, consistently favoring the β-anomer. Further transformation of compound 5 involved α-selective phosphite formation using dibenzyl N,N-diisopropylphosphoramidite and 5-(ethylthio)-1H-tetrazole. The resulting α
- -phosphite intermediate was then oxidized with hydrogen peroxide to yield dibenzyl α-phosphate 6, achieving an overall yield of 89% for these two steps. Removal of the 2-(phenylsulfonyl)ethanol protecting group in compound 6 was successfully achieved through treatment with 1,8-diazabicyclo[5.4.0]undec-7-ene
Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units
Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8
- variety of reactions; that are, phosphite- or Lawesson’s reagent-mediated olefination reactions (to introduce DTF motifs), Ramirez/Corey–Fuchs dibromo-olefinations followed by Sonogashira couplings (to introduce enediynes motifs), and Knoevenagel condensations (to introduce the vinylic diester motif). By
- explore further annellation of dihydropyrrole and pyrrole units at the DTF moiety of an IF-DTF. A phosphite-mediated coupling of either 1,3-dithiole-2-thione 2, 7, or 8 with IF dione 1 afforded IF-DTFs 9–11, as shown in Scheme 1. Compound 11 was also obtained from building block 4 via the pyrrolo
- reduction (generation of 14πz-aromatic ring) or oxidation (generation of 1,3-dithiolium ring). Synthetically, the work relies on using indenofluorene diones as key building blocks for performing olefination reactions, such as phosphite- or Lawesson’s reagent-mediated couplings, Ramirez/Corey–Fuchs dibromo
Synthesis of ether lipids: natural compounds and analogues
Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96
- 1H-tetrazole to produce the trialkyl phosphite 8.3 that was oxidized with tert-butyl hydroperoxide to produce phosphate 8.4. Then, β-elimination of the cyanoethyl protecting group produced PAF with a global yield of 70%. The limit of this method arises from the instability of the precursor 8.1 for
- ) myo-inositol (20.6). The oxidation of the phosphite intermediate with m-CPBA followed by the catalytic hydrogenolysis of the benzyl protecting groups produced PIP3-PAF (20.7). 2 Edelfosine and diether analogues PAF and PAF-analogues that feature an acyl or more generally an ester group in sn-2
- 22.10. However, the last step features the lower yield (54%) of this 8-step synthesis. In 1994, Bittman et al. reported an alternative strategy to introduce the phosphocholine moiety by the preparation of a cyclic phosphite as a key intermediate [119]. This one-pot three-step sequence starts with the
Eschenmoser coupling reactions starting from primary thioamides. When do they work and when not?
Beilstein J. Org. Chem. 2023, 19, 808–819, doi:10.3762/bjoc.19.61
- desirable ECR product 9a in 62% or 55% yield (entries 3 and 7 in Table 1) together with other decomposition products from which only thiobenzamide and benzonitrile were identified. In pure trimethyl phosphite (Table 1, entry 8) that acts simultaneously as polar solvent and mild thiophile, the parallel
- formation of products 8a and 8a-Me was observed, but their combined yield was lower than in DMF or MeCN. The introduction of the N-methyl group coming from trimethyl phosphite must occur prior to the dehydration step of the intermediary thiazole 7a because heating of independently prepared 8a with trimethyl
- phosphite does not give 8a-Me at all. The combined yield of 8a and 8a-Me can be increased when trifluoroacetic acid is added (Table 1, entry 9). Its role probably involves an acid-catalyzed elimination of a water molecule from 7a or 7a-Me. On the other hand, the addition of a stronger base (triethylamine
Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles
Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44
- (phosphite/phosphine-pyridine amide, phosphine-sulfoxide, phosphoramidite, MINBOL, see Figure 1) and they usually showed excellent diastereoselectivity (dr >20:1). The catalytic systems even with low catalyst loadings tolerated both electron-donating and withdrawing groups on the aromatic substituents
- (Scheme 16). Within the framework of these domino reactions, we have mainly employed ferrocenyl phosphane ligands such as Taniaphos or Josiphos. In collaboration with Prof. Schmalz from Cologne University, we have also tested phosphite-phosphine ligands (e.g., L15) from their lab. The advantage of these
Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities
Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31
- to improve the water solubility of combretastatin D-2 (2) by converting it into a series of phosphate salts and other prodrugs. Thus, phosphorylation of combretastatin D-2 (2) using dibenzyl phosphite gave derivative 183. Further cleavage of the benzyl groups using TMSBr followed by the reaction of
Identification and determination of the absolute configuration of amorph-4-en-10β-ol, a cadinol-type sesquiterpene from the scent glands of the African reed frog Hyperolius cinnamomeoventris
Beilstein J. Org. Chem. 2023, 19, 167–175, doi:10.3762/bjoc.19.16
- cleanly obtained in 75% yield from triethyl phosphite and 3-chloro-2-methylpropene by addition of NaI [14]. Subsequent reduction of the ester with LiAlH4 and oxidation with IBX gave aldehyde 7 in 95% yield. Grignard addition of vinylmagnesium bromide afforded the alcohol 8, which comprised the desired
Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field
Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179
- ][72]. A recent achievement of the enantioselective hydroxylation of α‑aryl-δ-lactams by O2 is shown in Scheme 5 [73] as an example of such organocatalyzed reaction type. Triethyl phosphite is added to reduce a hydroperoxide, which is initially formed by the enolate oxidation with O2. In summary
An alternative C–P cross-coupling route for the synthesis of novel V-shaped aryldiphosphonic acids
Beilstein J. Org. Chem. 2022, 18, 1518–1523, doi:10.3762/bjoc.18.160
- order of addition of reactants to perform the transition-metal-catalyzed C–P cross-coupling reaction, often referred to as the Tavs reaction, employing NiCl2 as a pre-catalyst in the phosphonylation of aryl bromide substrates using triisopropyl phosphite. This new method was employed in the synthesis of
- between a primary alkyl halide and a trialkyl phosphite, first reported in the late 1890s, the general scheme for which can be seen in Supporting Information File 1, Scheme S1 [22]. It should be noted that this reaction is not suitable for use with aryl halide substrates due to the poor reactivity between
- ) acetate and palladium(II) chloride [23][27][28]. Reactions involving these catalysts are most often carried out at high temperatures, usually in excess of 160 °C, and involve slow dropwise addition of the trialkyl phosphite to the substrate [23]. In the search for milder reaction conditions, a new
Synthesis and electrochemical properties of 3,4,5-tris(chlorophenyl)-1,2-diphosphaferrocenes
Beilstein J. Org. Chem. 2022, 18, 1338–1345, doi:10.3762/bjoc.18.139
- bromides from one starting aryl aldehyde. Diethyl phosphite was allowed to react with appropriately substituted benzaldehydes in THF for 48 hours at 25 °C to afford diethyl (hydroxy(aryl)methyl)phosphonates 1, which were detected by 31P NMR spectroscopy in THF (21.4 ppm for 1a, 21.0 ppm for 1b, and 21.5
Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C–Si bond functionalization
Beilstein J. Org. Chem. 2022, 18, 1256–1263, doi:10.3762/bjoc.18.131
- , but the yield of product 21 remained the same (Table 1, entry 4). In spite of the satisfactory yield of 21, these conditions were synthetically impractical as we were unable to conveniently separate the final product from the phosphite ligand. The use of a ligand for copper revealed to be necessary
Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide
Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125
- group as well as others, suggest that the broad resonance corresponds to a largely amorphous phase with predominately phosphate and phosphite-like environments, with the broad resonance at −8.9 ppm possibly corresponding to hydrated sodium phosphate byproducts [43][44]. The NMR spectrum of the g-h
Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides
Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90
- ) from the reaction of dimethyl 2-(methylamino)benzoylphosphonate (70) and trimethyl phosphite at 105 °C through an ylide intermediate D. The ylide D was generated via deoxygenation of benzoylphosphonate 70 with trimethyl phosphite to form a carbene intermediate B, and trimethyl phosphite nucleophilic
- complex showed 23% enantiomeric excess in the asymmetric borane reduction of acetophenone in THF at room temperature (Scheme 33) [58]. The reaction of 3-(phenylaminomethylene)-2-phenylamino-6-methyl-2,3-dihydro-4H-chromen-4-one (213) and diethyl phosphite at 90–100 °C generated 2-ethoxy-6-methyl-2-oxo-1
- reaction of 2-imino-2H-chromene-3-carboxamide (228) and diethyl phosphite at 80–90 °C under the catalysis of boron trifluoride, afforded 4-amino-1-ethoxy-9b-hydrochromeno[4,3-c][1,2]azaphosphol-3(2H)-one 1-oxide (229) in 40% yield through the Michael addition and subsequent tautomerization and
Direct C–H amination reactions of arenes with N-hydroxyphthalimides catalyzed by cuprous bromide
Beilstein J. Org. Chem. 2022, 18, 647–652, doi:10.3762/bjoc.18.65
- the amidyl radical precursor under air is reported. A possible mechanism is proposed that proceeds via a radical reaction in the presence of CuBr and triethyl phosphite. Keywords: amination; copper; N-hydroxyphthalimides; radical reactions; triethyl phosphite; Introduction Practical methods for
- (40 mol %) in the presence of P(OEt)3 (6 equiv, triethyl phosphite) under air at 100 °C (Table 1). The yield of the corresponding amide 3a was 78% (Table 1, entry 1). The reaction was completely inhibited in the absence of the copper catalyst or P(OEt)3, and no product was detected (Table 1, entries 2
- and 3). Different copper salts were tested and the reactions proved to be less efficient (Table 1, entries 4 and 5). Except for triethyl phosphite, the reaction could not be carried out with other phosphorus species (Table 1, entries 6–8). The optimum result was obtained when benzene was employed as
Silica gel and microwave-promoted synthesis of dihydropyrrolizines and tetrahydroindolizines from enaminones
Beilstein J. Org. Chem. 2021, 17, 2543–2552, doi:10.3762/bjoc.17.170
- bromide in acetonitrile at ambient temperature to produce the putative S-alkylated salt was complete within 18 hours, after which treatment with triethyl phosphite and triethylamine rapidly completed the sulfide contraction, giving (E)-enaminone 15a in 92% yield after chromatographic purification. The
- [57][58][59][60][61][62][63][64][65]. Results are summarized in Table 2. Triphenylphosphine and triethyl phosphite could be used interchangeably in the sulfur extrusion step. However, in most cases the co-elution of enaminones 15 with phosphorus-derived byproducts during chromatographic purification
- and 4-nitro congeners in acetonitrile, followed by sulfide contraction of the resulting thioiminium ether salts with triethylamine and triethyl phosphite, afforded the (E)-enaminones 25a–c in yields of 86–89%. The E-geometry of 25a was again confirmed by NOESY NMR spectroscopy, which showed an
A novel methodology for the efficient synthesis of 3-monohalooxindoles by acidolysis of 3-phosphate-substituted oxindoles with haloid acids
Beilstein J. Org. Chem. 2021, 17, 2321–2328, doi:10.3762/bjoc.17.150
- . Thus, further work is needed to develop a novel strategy for an efficient synthesis of such a versatile synthon. On the other hand, diethyl (2-oxoindolin-3-yl) phosphates 2 were easily prepared by the base-catalyzed phospha-Brook rearrangement of isatins 1 with diethyl phosphite [28][29]. This compound
Synthetic reactions driven by electron-donor–acceptor (EDA) complexes
Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67
- solvent (Scheme 57). The complex is bound together by weak halogen bonds, in which phosphorus lone-pair electrons interact with σ* orbitals of C–I bonds. A variety of arylphosphonates can be directly afforded by the simple combination of diaryliodonium salts and phosphite esters. In addition, calculations
DNA with zwitterionic and negatively charged phosphate modifications: Formation of DNA triplexes, duplexes and cell uptake studies
Beilstein J. Org. Chem. 2021, 17, 749–761, doi:10.3762/bjoc.17.65
- modifications were introduced into the DNA backbone using the Staudinger reaction between the 3’,5’-dinucleoside β-cyanoethyl phosphite triester formed during DNA synthesis and sulfonyl azides, 4-(azidosulfonyl)-N,N,N-trimethylbutan-1-aminium iodide (N+ azide) or p-toluenesulfonyl (tosyl or Ts) azide, to
Synthesis of (Z)-3-[amino(phenyl)methylidene]-1,3-dihydro-2H-indol-2-ones using an Eschenmoser coupling reaction
Beilstein J. Org. Chem. 2021, 17, 527–539, doi:10.3762/bjoc.17.47
- thiophiles. First, we added triphenylphosphine (1 equiv) but an even more complex mixture of products resulted. Much better results were obtained when trimethyl phosphite was used but this strongly depended on the used molar ratio: the best yield of the product 7aa (83%) was achieved when using 1.5 equiv of
- trimethyl phosphite. While a lower amount (1 equiv) had only a moderate influence on the reaction progress (yield of 7aa was 50%) a higher amount (3 equiv) caused a significant reduction of 1a to the parent oxindole (yield of 7aa was 44%). Therefore, the optimized amount (1.5 equiv) was used for the
- with another portion (50 mL) of CHCl3/CH3OH 1:1. The collected filtrates were dried and evaporated. Synthesis of 3-[dimethylamino(phenyl)methylidene]-1,3-dihydro-2H-indol-2-ones (7aa–ca) The 4-substituted N,N-dimethylthiobenzamide (4a–c, n4a–c) and trimethyl phosphite (1.5 equiv) were dissolved in a
1,2,3-Triazoles as leaving groups in SNAr–Arbuzov reactions: synthesis of C6-phosphonated purine derivatives
Beilstein J. Org. Chem. 2021, 17, 193–202, doi:10.3762/bjoc.17.19
- -phosphonate synthesis. They can be obtained by 1) the reaction of a lithiated C8 position with diethyl chlorophosphate (C→D, Scheme 1) [14] and 2) an intermolecular [15] or intramolecular [16] photochemical reaction between 8-bromopurine derivatives and phosphite (E→F and G→H, respectively, Scheme 1). Further
- phosphite. The SNAr–Arbuzov reaction between 2,6-dichloropurine derivative 1 and triethylphosphite gave product 2a in 82% yield (Scheme 3) [12]. Next, attempts to substitute the chlorine atom at the purine C2 position were made using either NaN3 or TBAN3. Azidation experiments were tried in solvents such as
- toluene, MeCN, and DCM, and in the presence of 1–20 equiv of P(OEt)3, the formation of the desired phosphonates 4 was not observed (Scheme 6). We started an optimization of the reaction conditions using substrate 6d, and reactions in neat phosphite at various temperatures were tried (Table 2). The
Progress in the total synthesis of inthomycins
Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7
- bromine in acetic acid, and then triethyl phosphite. Next, compound 28 was treated with sodium hydride followed by aldehyde 29 [37] to give (E,E)-dienyl stannane 30 in 50% yield. The key Stille coupling between 30 and vinyl iodide 31, prepared by Takai reaction [38] of phenylacetaldehyde, in presence of
Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine
Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4
- intermediate thioiminium salt, which was heated under the reflux of triethylamine and trimethyl phosphite, providing compound 28 in 69% yield. The catalytic hydrogenation of 28 occurred in platinum (H2, Pt/C) under a pressure of 60 psi of hydrogen (about 4 atm), resulting in amide 29 in 96% yield. This
- -Ni (W-2), H2O, 30 °C, 95%; vii) PCC, CH2Cl2, rt, 30%. Synthesis (+)-euphococcinine (2). Reagents and conditions: i) 2,4-bis(4-phenoxyphenyl)-1,3-dithia-2,4-diphosphetane 2,4-disulfide (Belleau’s reagent), 100%; ii) 33, triethylamine, trimethyl phosphite, reflux, 69%; iii) H2 (60 psi), Pt/C, Na2CO3
Silver-catalyzed synthesis of β-fluorovinylphosphonates by phosphonofluorination of aromatic alkynes
Beilstein J. Org. Chem. 2020, 16, 3086–3092, doi:10.3762/bjoc.16.258
- 200032, P. R. China 10.3762/bjoc.16.258 Abstract A silver-catalyzed three-component reaction involving alkynes, Selectfluor®, and diethyl phosphite was employed for the one-pot formation of C(sp2)–F and C(sp2)–P bonds to provide an efficient access to β-fluorovinylphosphonates in a highly regio- and
- vinylphosphonates from simple and commercially available alkynes proceeds under mild conditions with high stereoselectivity, and thus enabling the rapid construction of molecular complexity. Results and Discussion We investigated the reaction of phenylacetylene (1a), Selectfluor®, and diethyl phosphite to afford β
- the absence of a silver catalyst (Table 1, entry 16). The extensive screening of these reaction parameters revealed that the treatment of the alkynes 1 with Selectfluor®, diethyl phosphite, and silver acetate as the catalyst as well as DCE/H2O 1:1 as the solvent at 60 °C afforded the optimal result
Synthesis and characterization of S,N-heterotetracenes
Beilstein J. Org. Chem. 2020, 16, 2636–2644, doi:10.3762/bjoc.16.214
- derivatives by Cadogan reaction of nitro-substituted precursors. Another possibility for the preparation of fused pyrrole rings is established by the Cadogan reaction [40]. Well-known examples are the reductive cyclization of 2-nitro-1,1’-biphenyls with triethyl phosphite or phosphanes as reducing agent to
- 3-nitro-2,2’-bithiophene with triethyl phosphite under microwave irradiation and surprisingly obtained targeted heterotriacene H-DTP (vide supra) with only 11% yield [45]. This result prompted us to have a closer look on the applicability of the Cadogan reaction/cyclization in order to provide S,N
- a Pd-catalyzed Stille-type cross-coupling with 2-bromo-3-nitrothiophene (15) to precursor 2-(3-nitrothien-2-yl)thieno[3,2-b]thiophene (16) in 64% yield. Cadogan cyclization of nitro derivative 16 with triethyl phosphite at reflux gave 4H-thieno[3,2-b]thieno[2’, 3’:4,5]thieno[2,3-d]pyrrole (H-SN4, 13
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