Regioselective Synthesis of 2‐and 3‐Aryl‐1,4‐benzodioxanes

Antus, Sándor; Gottsegen, Á.; Baitz-Gács, Eszter; Bauer, R.; Seligmann, Otto; Wagner, Hildebert

doi:10.1002/jlac.198919890286

Cited by 32 publications

(25 citation statements)

References 20 publications

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“…64,65 It was revealed that the substituents on the catechol fragment (i.e. 28 in Scheme 3) have a strong effect on the regioselectivity of the reaction; electron donating substituents, like methyl as in 28, strongly favour the formation of 3-aryl products (e.g.…”

Section: Further Developments and Application Of Biomimetic Methodsmentioning

confidence: 99%

Synthesis and biology of 1,4-benzodioxane lignan natural products

Pilkington

Barker

2015

Nat. Prod. Rep.

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Section: Further Developments and Application Of Biomimetic Methodsmentioning

confidence: 99%

Synthesis and biology of 1,4-benzodioxane lignan natural products

Pilkington

Barker

2015

Nat. Prod. Rep.

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“…The mixture was stirred at room temperature for 2 h, then saturated NH 4 Cl was added, and the mixture stirred, extracted with ethyl acetate and dried, the solvent was evaporated o and the crude product was puri®ed by¯ash chromatography using light petroleum and ethyl acetate (2)-3-Methoxybenzodioxane-4,9,9'-triol Neolignan 9.ÐA solution of 8 (30 mg) in methanol (30 ml) was hydrogenated over 10% Pd/C (5 mg) under H 2 for 40 min. Then the reaction mixture was ®ltered through silica gel and preparative TLC aorded 9 as a colorless oil, 29 mg, 97% yield; H (400 MHz, [ 2 H 6 ]acetone): 1.78 (m, 2H, H-8'), 2.58 (t, 2H, J 7.7, H-9'), 3.47 and 3.69 (dd, 1H, J 12, 4, H-9), 3.55 (t, 2H, J 6.5, H-7'), 3.85 (s, SH, OCH 3 All the spectral data were in good agreement with those reported. 2 We are grateful to the National Science Foundation of China for ®nancial support.…”

Section: Methodsmentioning

confidence: 99%

A Convenient Synthesis of (±)-3-Methoxybenzodioxane-4,9,9′-triol Neolignan, and Methyl Ethers of Isoamericanol A and Isoamericanin A

She

et al. 1999

J. Chem. Res.

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The (2)-3-methoxybenzodioxane-4,9,9'-triol neolignan 9, and methyl ethers of isoamericanol A 8 and isoamericanin A 7 were synthesized from the readily available materials caffeic acid and ferulic acid, using a coupling reaction as a key step.Isoamericanol A, isoamericanin A and (2)-3-methoxybenzodioxane-4,9,9'-triol neolignan are three neolignans isolated from phytocaccaceae and Juniperns chinesis 1,2 and were assigned structure 7 H H H , 8 H H H and 9 respectively through spectral studies. In the literature it is reported that natural products containing the 1,4-benzodioxane ring have cytotoxic and hepatoprotective, 3 and other biological activity associated with the 1,4-benzodioxane group, 4 but no syntheses of these particular natural products have been reported.In order to study methods of construction of the 1,4-benzodioxane ring and the structure±activity relationship, we developed a facile synthetic route to (2)-3-methoxybenzodioxane-4,9,9'-triol neolignan 9, and methyl ethers of isoamericanol A 7 and isoamericanin A 8, in which use of silver carbonate as the oxidizing agent resulted in higher regioselectivity (ca. 30:1) than that obtained with silver oxide (ca. 20 :1) by Merlini et al. 5 As shown in Scheme 1, 3-(3,4-dihydroxy)phenylprop-2-enoate 5 and ferulic alcohol 3 were synthesized from the starting materials caeic acid and ferulic acid based on an earlier report, 3 then compounds 3 and 5 were converted into key intermediate 6 by a coupling reaction, which was then reduced with LiAlH 4 ±AlCl 3 (3 :1) to aord alcohol 7. Then 7 was hydrogenated to get the target compound 9 and was oxidized with MnO 2 ±SiO 2 to obtain compound 8. ExperimentalMelting points were measured on a Ko¯er apparatus and were uncorrected. Mass spectra were recorded on a ZAB-HS spectrometer. Elemental analyses were performed on a Carlo-Erba 1106 instrument. IR spectra were recorded on a Nicolet 170 SXFT-IR spectrometer. 1 H NMR spectra were recorded on a Bruker Ac-80 J. Chem. Research (S), 1999, 100±1016Scheme 1 Reagents and conditions: i: CH 3 OH, H 2 SO 4 , reflux; ii; LiAlH 4 , AlCl 3 room temp.; iii, Ag 2 CO 3 , acetone±benzene (1: 2), room temp.; iv, MnO 2 ±SiO 2 , CH 2 Cl 2 room temp.; v: H 2 , Pd/C (10%) and AM-400 instrument. Chemical shifts are referenced to Me 4 Si on the d scale. J values are in Hz. Standard¯ash chromatography was employed to purify the crude reaction mixture using ca. 200 H300 mesh silica gel under positive nitrogen pressure.

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“…30 In addition, a remarkable selectivity of the dirhodium reagent has been noticed when binding to substrates with more than one heterotopic ligand sites, such as various carbonyls, aromatic iso-and heterocycles, and so forth. [90][91][92] In experiments allowing intramolecular competition, e.g., with the racemic 2,3-trans-dihydro-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-1,4-benzodioxin-6-yl]-2(E)-propenoic acid ethyl ester (53; Scheme 18), 93,94 we found that a carbonyl oxygen seems always to be the better donor as compared with ether-like oxygen functionalities, as expected. 95 Clearly, there is no complexation at the 1,4-dioxane ring moiety or the methoxy group but at the ester carbonyl (Scheme 18, top); whereas signal resolution (dispersion) is found all over the molecule.…”

Section: Ethers-chiral Recognition By Nmr Spectroscopy General Princimentioning

confidence: 99%

Chiral recognition of ethers by NMR spectroscopy

Duddeck

Gómez

2008

Chirality

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Enantiomers of chiral ethers and acetals are notoriously difficult to differentiate because their reactivity is low and they are poor donors to any Lewis acid or metal ion. As an exception, epoxides are somewhat better donors. This review describes the properties of ethers, explains NMR methods for their chiral recognition and describes successful examples of ether differentiation. The majority of literature reports deals with chiral lanthanide shift reagents and dirhodium tetracarboxylate complexes, which were used as enantiopure auxiliaries to create diastereomeric adducts with dispersed (1)H and (13)C NMR signals. The various methods are compared as to which is best suited for which purpose.

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Regioselective Synthesis of 2‐and 3‐Aryl‐1,4‐benzodioxanes

Cited by 32 publications

References 20 publications

Synthesis and biology of 1,4-benzodioxane lignan natural products

Synthesis and biology of 1,4-benzodioxane lignan natural products

A Convenient Synthesis of (±)-3-Methoxybenzodioxane-4,9,9′-triol Neolignan, and Methyl Ethers of Isoamericanol A and Isoamericanin A

Chiral recognition of ethers by NMR spectroscopy

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