Stereoselective syntheses and reactions of chiral oxygenated α,β-unsaturated-γ- and δ-lactones

Sánchez-Sancho, Francisco; Valverde, Serafı́n; Herradón, Bernardo

doi:10.1016/0957-4166(96)00424-7

Cited by 54 publications

(16 citation statements)

References 186 publications

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“…The AlCl 3 mediated debenzylation of (±)-18 in m-xylene afforded the racemic natural product (±)-3 in 82% yield. The NMR data of the synthetic (±)-18 and (±)-3 were identical with those of the reported (+)-18 7) and (+)-3, 7) respectively. γ-Lactonization from (S)-4,5-Dihydroxy-(2E)-pentenoic Acid (21) (Synthesis of (S)-22) (Chart 4) The (S)-5-hydroxy-2-penten-4-olide (22) was obtained as an aglycone from a glycoside, ranunculin, which was isolated from Pulsatilla vulgaris MiLL.…”

Section: γ-Lactonization From (±)-(45-anti)-5-benzyloxy-4-hydroxy-(2supporting

confidence: 65%

Synthesis of γ- and δ-Lactone Natural Products by Employing a trans–cis Isomerization/Lactonization Strategy

2013

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Alkaline hydrolysis of 4-hydroxy-or/and 5-hydroxy-(2E)-alkenoate followed by acid treatment gave the corresponding (2E)-alkenoic acids which were subjected to lactone formation reaction without further purification. The crude acids were treated with 2,4,6-trichlorobenzoyl chloride in pyridine to afford γ-lactone or δ-lactone, respectively, accompanied by trans-cis isomerization. By this procedure, (±)-(4,5)-trans-5-benzyloxy-2-hexen-4-olide (90% overall yield), (S)-5-hydroxy-2-penten-4-olide (86% overall yield), (4S,5R)-5-hydroxy-2-hexen-4-olide (86% overall yield), (4R,5S)-5-hydroxy-2-hexen-4-olide (82% overall yield), (S)-parasorbic acid (58% overall yield) and natural product, (5R,7S)-7-hydroxy-2-octen-5-olide (euscapholide: 20% overall yield) were synthesized.

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Section: γ-Lactonization From (±)-(45-anti)-5-benzyloxy-4-hydroxy-(2supporting

confidence: 65%

Synthesis of γ- and δ-Lactone Natural Products by Employing a trans–cis Isomerization/Lactonization Strategy

2013

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“…The extract was dried (MgSO 4 ) and evaporated. The crude product was purified by chromatography to give 17 (0.16 g, 84%) as 1:1 mixture of two C-1Ј epimers; 1 (19). Compound 17 (0.13 g, 0.4 mmol) in dichloromethane (1 ml) was treated with TEA (0.14 ml, 1 mmol) and TMSOTf (0.14 ml, 0.8 mmol) at room temperature under nitrogen.…”

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confidence: 99%

Six‐membered cyclic sulfites derived from glucofuranose and 1,2,4‐butanetriol

et al. 2001

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Six-membered cyclic sulfites derived from glucofuranose derivatives 5, 6 and from 1-O-tert-butyldimethylsilil-1,2,4-butanetriol 12 were synthesized and separated into pure diastereomers which were in turn subjected to the sequence of reactions leading to the introduction of the terminal vinyl ether fragment. Reactivity and applicability of cyclic sulfites as intermediates in [2+2]cycloaddition of chlorosulfonyl isocyanate (CSI) to vinyl ethers were studied. The cycloaddition to vinyl ethers 19 and 20 proceeded in low yield and low asymmetric induction, in the case of the former, and moderate yield and pronounced asymmetric induction, in the case of the latter. The (1)H-NMR spectra of sulfites 13-16 reveal a preference of the sulfite oxygen atom for the axial position. Thus, well-defined conformation in solution for compounds 13 and 15 and a mixture of the two possible chair forms for sulfites 14 and 16 could be assigned. The stretching frequency of the S-->O bond in stable conformation with an axial sulfite oxygen occurs in the range 1,160-1,210 cm(-1), whereas conformationally mobile sulfites exhibit corresponding absorption above 1,220 cm(-1). The absolute configuration assignments of sulfites 7, 8, 15, 16 and 25-28 were done empirically based on the combined analysis of the NMR, IR, X-ray, and dichroic data. It was demonstrated that the sign of the Cotton effect around 194 nm correlated with the absolute stereochemistry at the sulfur atom in a sulfite chromophore.

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“…Another model reaction involved imine 15 , since alkoxyallene adducts derived thereof might be highly suitable for the planned (−)‐detoxinine synthesis (see below). The ultimate precursor of 15 was ( S )‐malic acid, which was smoothly reduced to a chiral 1,2,4‐butanetriol 10. Regioselective protection of this triol furnished 1,3‐dioxane derivative 14 in excellent overall yield (Scheme ) 11.…”

Section: Resultsmentioning

confidence: 99%

A Stereoselective and Short Total Synthesis of the Polyhydroxylated γ‐Amino Acid (−)‐Detoxinine, Based on Stereoselective Preparation of Dihydropyrrole Derivatives from Lithiated Alkoxyallenes

Flögel

Amombo

Reißig

et al. 2003

Chemistry A European J

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Based on our earlier results employing lithiated methoxyallene 2 as C(3) building block and imines 3 for the synthesis of dihydropyrrole derivatives 5, we have investigated chiral imines 6, 10, and 15 as electrophilic components. Combined with lithiated alkoxyallenes, these imines provide the corresponding primary adducts and finally the dihydropyrrole derivatives 8, 12, 17, 20, and 22 in good yields and with high to excellent syn selectivities. This stereochemical outcome is interpreted as a result of alpha-chelate control. Treatment with hydrochloric acid converted syn-8 and syn-12 into bicyclic compounds 9 and 13, whereas under more mildly acidic conditions adduct syn-17 was transformed into diol syn-18. The total synthesis of the uncommon gamma-amino acid (-)-detoxinine could be achieved by starting from (S)-malic acid, which was converted into imine 15 in four steps. Lithiated benzyloxyallene added to imine 15 and efficiently furnished the crucial dihydropyrrole derivative syn-22. The hydrogenolysis of this compound did not directly provide the protected triol 29 as anticipated, but a stepwise protocol made the triol available in a fairly satisfactory manner. A second crucial step of the synthesis was the selective oxidation of 29, which could be achieved by employing platinum dioxide and oxygen. The resulting bicyclic lactone 30 was smoothly transformed into enantiopure (-)-detoxinine. Thus, a fairly short synthesis of this natural product based on a lithiated alkoxyallene could be performed, demonstrating the potential of these intermediates for syntheses of interesting functionalized heterocyclic compounds.

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Stereoselective syntheses and reactions of chiral oxygenated α,β-unsaturated-γ- and δ-lactones

Cited by 54 publications

References 186 publications

Synthesis of γ- and δ-Lactone Natural Products by Employing a trans–cis Isomerization/Lactonization Strategy

Synthesis of γ- and δ-Lactone Natural Products by Employing a trans–cis Isomerization/Lactonization Strategy

Six‐membered cyclic sulfites derived from glucofuranose and 1,2,4‐butanetriol

A Stereoselective and Short Total Synthesis of the Polyhydroxylated γ‐Amino Acid (−)‐Detoxinine, Based on Stereoselective Preparation of Dihydropyrrole Derivatives from Lithiated Alkoxyallenes

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