Stereoselective acetate aldol reactions of α-silyloxy ketones

Lorente, Adriana; Pellicena, Miquel; Romea, Pedro; Urpı́, Fèlix

doi:10.1016/j.tet.2014.12.099

Cited by 8 publications

(5 citation statements)

References 74 publications

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“…COSY correlations of H 2 -2′ (δ H 2.34)/H 2 -3′ (δ H 3.67), H 2 -3′/H-4′ (δ H 1.67), H-4′/H 3 -5′ (δ H 0.93), and H-4′/H 3 -6′ (δ H 0.90) and HMBC correlations from H 2 -2′ and H-12 (δ H 5.45) to C-1′ (δ C 172.3), along the molecular formula, confirmed the hydroxy substitution at C-3′ (δ C 72.8) in 3 (Figure ). The absolute configuration of C-3′ was determined to be R by comparison of the specific rotations of ( R )-3-hydroxy-4-methylpentanoic acid ([α] D +39.8, CHCl 3 , c 1.0) with ( S )-3-hydroxy-4-methylpentanoic acid ([α] D −25.3, CHCl 3 , c 1.2) − and those of 3 ([α] D 25 +62.7, MeCN, c 0.1) with 2 ([α] D 25 +40.7, MeCN, c 0.1), respectively. Additionally, the specific rotation of the 3-hydroxy-4-methylpentanoic acid subunit in 3 ([α] D 25 +2.1, CHCl 3 , c 0.1) (differences in measured versus literature values likely stem from inaccuracies in the weight of this hydrolysis fragment), determined after hydrolysis and purification by mini-chromatographic column on silica gel (200 mesh, CH 2 Cl 2 /MeOH, 20:1), confirmed the R -configuration for C-3′.…”

Section: Resultsmentioning

confidence: 99%

Phyllospongianes A–E, Dinorscalarane Sesterterpenes from the Marine SpongePhyllospongia foliascens

Yu,

Hu,

et al. 2023

J. Nat. Prod.

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Phyllospongianes A–E (1–5), five new scalarane derivatives featuring an unprecedented 6/6/6/5 tetracyclic dinorscalarane scaffold, along with the known probable biogenetic precursor, 12-deacetylscalaradial (6), were isolated from the marine sponge Phyllospongia foliascens. The structures of the isolated compounds were determined by analysis of spectroscopic data and electronic circular dichroism experiments. Compounds 1–5 are the first 6/6/6/5 tetracyclic scalarane derivatives to be reported within the scalarane family. Compounds 1, 2, and 4 exhibited antibacterial activity against Vibrio vulnificus, Vibrio parahemolyticus, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and Pseudomonas aeruginosa with MIC values ranging from 1 to 8 μg/mL. Furthermore, compound 3 exhibited significant cytotoxic activity on MDA-MB-231, HepG2, C4-2-ENZ, MCF-7, H460, and HT-29 cancer cell lines with IC50 values in the range between 0.7 and 13.2 μM.

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Section: Resultsmentioning

confidence: 99%

Phyllospongianes A–E, Dinorscalarane Sesterterpenes from the Marine SpongePhyllospongia foliascens

Yu,

Hu,

et al. 2023

J. Nat. Prod.

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“…The relative configuration of 3 was identical to that of 2 in the comparison of their chemical shifts, the coupling constant of H-12, NOESY correlations (Figure 3), and CD spectra (Figure 4) [4,11]. The 3 R configuration was determined by comparing the specific rotations of (S)-3-hydroxy-4-methylpentanoic acid ([α] D −25.3, CHCl 3 , c 1.2) [13] with (R)-3-hydroxy-4-methylpentanoic acid ([α] D +39.8, CHCl 3 , c 1.0) [14,15] (δH 0.93) and HMBC correlations from H2-2′a and H-12 (δH 4.85) to C-1′ (δC 172.9) (Figure 2), along the molecular formula and 13 C NMR chemical shift of C-3′ (δC 72.7). The relative configuration of 3 was identical to that of 2 in the comparison of their chemical shifts, the coupling constant of H-12, NOESY correlations (Figure 3), and CD spectra (Figure 4) [4,11].…”

Section: Resultsmentioning

confidence: 99%

“…The relative configuration of 3 was identical to that of 2 in the comparison of their chemical shifts, the coupling constant of H-12, NOESY correlations (Figure 3), and CD spectra (Figure 4) [4,11]. The 3′R configuration was determined by comparing the specific rotations of (S)-3hydroxy-4-methylpentanoic acid ([α] D −25.3, CHCl3, c 1.2) [13] with (R)-3-hydroxy-4methylpentanoic acid ([α] D +39.8, CHCl3, c 1.0) [14,15] Phyllofenone I ( 4) was also isolated as a white powder, and its molecular formula was determined as C31H50O4 based on HRESIMS data (Table 2); it was 16 amu larger than that of 1. The IR spectrum indicated the presence of hydroxy (3535 cm −1 ) and carbonyl (1729 cm −1 ) groups [16].…”

Section: Resultsmentioning

confidence: 99%

Phyllofenones F–M, Scalarane Sesterterpenes from the Marine Sponge Phyllospongia foliascens

Yu,

Hu,

Ning

et al. 2023

Marine Drugs

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Eight new scalarane sesterterpenes, phyllofenones F–M (1–8), together with two known analogues, carteriofenones B and A (9–10), were isolated from the marine sponge Phyllospongia foliascens collected from the South China Sea. The structures of these compounds were determined based on extensive spectroscopic and quantum chemical calculation analysis. The antibacterial and cytotoxic activity of these compounds was evaluated. Among them, only compounds 4 and 6 displayed weak inhibitory activity against Staphylococcus aureus and Escherichia coli, with MIC values of 16 μg/mL and 8 μg/mL, respectively. Compounds 1–10 exhibited cytotoxic activity against the HeLa, HCT-116, H460, and SW1990 cancer cell lines, with IC50 values ranging from 3.4 to 19.8 μM.

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“…Attribution of 1 H spectrum is detailed on Figure . 1 H and C NMR chemical shifts are displayed in Table and compared with those of similar aldehydes from the literature …”

Section: Resultsmentioning

confidence: 99%

Acetalization of poly(vinyl alcohol) by a fatty aldehyde in water medium: Model study, kinetics, and structure analysis

Piluso

Boisson

Bounor‐Legaré

et al. 2017

J. Polym. Sci. Part A: Polym. Chem.

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Acid catalyzed poly(vinyl alcohol) (PVA) acetalization was investigated in aqueous medium at 80 8C for a PVA concentration of 8 wt %. The reactant, 10-undecenal, was composed of a long alkyl chain with a vinyl end group, and the functionalization reaction was studied in heterogeneous media for low reactant concentrations (from 0.33 to 2.0 mol % compared with PVA hydroxyl groups concentration). First, the reaction was scrutinized with pentane-2,4-diol, as a model compound of PVA. Besides the expected reaction, the oxidation of the aldehyde into 10-undecenoic acid in the presence of water was evidenced. This carboxylic acid appeared unreactive toward esterification of pentane-2,4-diol and PVA in water. Characterization of acetal stereochemical structure formed on the PVA backbone was performed by NMR spectroscopy in accordance to the model approach. A protocol based on 1 H NMR analysis was developed to quantify grafted aldehyde, residual aldehyde, and created carboxylic acid through direct sampling of the reaction medium. Conversions and reaction rate constants were calculated for pH ranging from 1 to 3. Finally, the acetalization yield was found to be enhanced at low pH and, in such conditions, the oxidation reaction contribution was limited.

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Stereoselective acetate aldol reactions of α-silyloxy ketones

Cited by 8 publications

References 74 publications

Phyllospongianes A–E, Dinorscalarane Sesterterpenes from the Marine SpongePhyllospongia foliascens

Phyllospongianes A–E, Dinorscalarane Sesterterpenes from the Marine SpongePhyllospongia foliascens

Phyllofenones F–M, Scalarane Sesterterpenes from the Marine Sponge Phyllospongia foliascens

Acetalization of poly(vinyl alcohol) by a fatty aldehyde in water medium: Model study, kinetics, and structure analysis

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