Biogenesis of lung-toxic furans produced during microbial infection of sweet potatoes (Ipomoea batatas)

Burka, Leo T.; Kuhnert, L.; Wilson, Benjamin J.; Harris, Thomas M.

doi:10.1021/ja00449a046

Cited by 23 publications

(4 citation statements)

References 2 publications

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“…The β-ketosulfone ( R / S , R )- 27 was synthesized in 89% overall yield in a two-step procedure by aldol-type addition of furan-3-carboxaldehyde ( 26 ) to the α-lithio derivative of ( R )- 25 followed by subsequent Swern oxidation (de = 23%). Simultaneous removal of both the acetal protecting group and the sulfone group of ( R / S , R )- 27 was accomplished by reaction with zinc dust under acidic aqueous conditions and gave (−)-( S )-myoporon ( S )- 28 in 93% yield (ee > 99%, HPLC on chiral Daicel OD phase) {[α] D 26 −7.0 ( c 1.39, MeOH) vs [α] D 25 −8.5 ( c 1.54, MeOH)}. 21f, Using enantiopure complexes 18 ‘ or 19 ‘/‘ ‘, several other natural products such as pheromones in their absolute natural configurations were synthesized, further supporting the stereochemical conclusions drawn from this study. 21d-f,i…”

Section: Resultssupporting

confidence: 59%

Iron-Mediated Allylic Substitution Reactions with Chirality Transfer. Stereochemistry of the Formation of Diastereo- and Enantiomerically Enriched Olefinic and Allylic Tetracarbonyl Iron Complexes

et al. 2001

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(E)-Configurated allylic ligands (S)-6a−f and (S)-8, bearing a leaving group at C(3) (allylic position) and an electron acceptor substituent at C(1), were synthesized from enantiopure (S)-ethyl lactate [(S)-1]. Complexation with Fe2(CO)9 (13) afforded diastereomeric mixtures of their (η2-alkene)tetracarbonyliron(0) complexes 14a‘/a‘ ‘−f‘/f‘ ‘ (acceptor group, Acc = SO2Ph) and 15‘/‘ ‘ (Acc = CO2Me) (48% − quant.; de < 3−70%), each diastereomer in enantiopure form (Note: descriptors ‘ and ‘ ‘ denote major and minor diastereomer). Synthetically useful results were obtained for allylic ligands bearing a benzylic protecting group [(S)-6a and (S)-8] and using hexane or diethyl ether as solvent (14a‘/a‘ ‘: quant., de = 70%; 15‘/‘ ‘: 75−88%, de = 10−16%). Complexes 14a‘/a‘ ‘ were fractionally crystallized, and their molecular structures were determined by X-ray diffraction, allowing for an assignment of the absolute configurations of complexes 14a‘/a‘ ‘−f‘/f‘ ‘ and 15‘/‘ ‘. “W”-shaped complexes 14a‘, 15‘ ‘ (Ψ-exo-14,15) were expected to yield syn-Me,syn-Acc-configured and “S”-shaped complexes 14a‘ ‘, 15‘ (Ψ-endo-14,15) accordingly anti-Me,syn-Acc-configured cationic complexes 18 and 19 upon treatment with HBF4. Complex 14a‘ (de = ee > 99%) reacted quantitatively to the syn-Me-substituted (η3-allyl)tetracarbonyliron(1+) complex 18‘ (syn-Me,syn-SO2Ph-18) (syn-Me/anti-Me > 99:1, ee > 99%). Diastereomeric mixtures of complexes 14a‘/a‘ ‘ gave mixtures of complexes 18‘, 18‘ ‘ (anti-Me,syn-SO2Ph-18) and ent-18‘ ‘ (ent-syn-Me,syn-SO2Ph-18). Conversion of complex 14a‘ ‘ to 18‘ ‘ or complex 18‘ ‘ itself was subjected to an anti-Me → syn-Me isomerization process, yielding eventually a diastereomeric mixture of complexes 18‘ ‘ and ent-18‘ ‘, thus lowering the overall enantiomeric purity of syn-Me,syn-SO2Ph-substituted complexes 18. Conversion of a mixture of 15‘/‘ ‘ (de = 10%) to cationic complexes 19‘/‘ ‘ did not exhibit significant anti-Me → syn-Me isomerization (syn-Me:anti-Me = 1:1.19, ee > 96% for both diastereomers). Nucleophilic anti-addition of silyl enol ether 20 to complex 18‘ or silyl ketene acetal 21 to a complex mixture 19‘/‘ ‘ afforded enantiopure alkenyl sulfone (R)-23 or ester (S)-24 (82% − quant., ee >96 to >99%). Addition to a complex mixture containing 18‘, 18‘ ‘, and ent-18‘ yielded 23, albeit with lower enantiomeric purity (ee = 59−66%). The chirality transfer process of the iron-mediated allylic substitution proceeds with overall retention (double inversion) of stereochemistry with respect to the stereogenic center of the starting materials, conservation of (E)-double bond geometry, and complete γ-regioselectivity for the nucleophilic addition reactions. Differences of configurative stability of the anti-configured Me groups in the cationic π-allyl complexes 18‘ ‘ and 19‘ were found requiring appropriate consideration if used in stereocontrolled organic synthesis.

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Section: Resultssupporting

confidence: 59%

Iron-Mediated Allylic Substitution Reactions with Chirality Transfer. Stereochemistry of the Formation of Diastereo- and Enantiomerically Enriched Olefinic and Allylic Tetracarbonyl Iron Complexes

et al. 2001

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“…Furans usually impart a certain sweet flavour 11,25 . During heating, 3 furans were identified from palmitoleic acid, including 2‐hexyl‐furan, 2‐pentyl‐furan and furfural.…”

Section: Resultsmentioning

confidence: 99%

“…10 Furans usually impart a certain sweet flavour. 11,25 During heating, 3 furans were identified from palmitoleic acid, including 2-hexyl-furan, 2-pentyl-furan and furfural. This result is consistent with that reported by Becalski and Seaman; that is, furan is an oxidative product of polyunsaturated fatty acids.…”

Section: Ta B L E 1 (Continued)mentioning

confidence: 99%

Mechanism of palmitoleic acid oxidation into volatile compounds during heating

Gao

Bao

Wang³

et al. 2023

Flavour & Fragrance J

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To better understand the mechanism of palmitoleic acid oxidation into volatile compounds during heating, volatile profiling was investigated by combining thermaldesorption cryo-trapping with gas chromatography-mass spectrometry. A total of 49 volatile compounds were detected and identified during this process, including aldehydes (18), ketones ( 14), alcohols (9), furans (3) and acids and ester (5). The forming temperature of each volatile was determined. Most of the volatiles with short carbon chains were generated at low temperatures, while those with long carbon chains were generated at high temperatures. Results of principal component analysis show that nearly all of the identified volatiles were considered as the characteristic ones of the high temperature points. Meanwhile, the oxidative products of the C7-C11 saturated and unsaturated aldehydes were also detected and identified during heating to intensively investigate the oxidative mechanism of palmitoleic acid during heating. Results demonstrated that only the C10 saturated and unsaturated aldehydes could continue to be oxidized during heating. Therefore, the oxidation reactions above the secondary level of lipids mainly occurred in the C10 saturated and unsaturated aldehydes.

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“…()-Sesquiterpene 4 is a stress metabolite which is produced by sweet potatoes infected with Fusarium solani [2] and possesses a strong lung toxic effect. [9] In addition, hydroxymyoporone was isolated from Athanasia grandiceps assuming that the obtained compound is the enantiomer of 4. However, the determination of the absolute configuration of both compounds seems rather questionable, since the optical rotation of the product isolated from sweet potatoes was never published.…”

Section: Introductionmentioning

confidence: 99%

First Total Synthesis and Determination of the Absolute Configuration of the Stress Factor (+)-Hydroxymyoporone

Tietze¹,

Wegner²,

Wulff³

1999

Chem. Eur. J.

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The first total synthesis of the stress factor ()-hydroxymyoporone (4) is presented. The key step is an asymmetric allylation of the methyl ketone 10 which proceeds with excellent selectivity and yield. In addition, it was proven that the assignment of the absolute configuration of hydroxymyoporone published in the literature is incorrect; the correct structure of the ()-enantiomer is depicted in the structural formula 4.

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Biogenesis of lung-toxic furans produced during microbial infection of sweet potatoes (Ipomoea batatas)

Cited by 23 publications

References 2 publications

Iron-Mediated Allylic Substitution Reactions with Chirality Transfer. Stereochemistry of the Formation of Diastereo- and Enantiomerically Enriched Olefinic and Allylic Tetracarbonyl Iron Complexes

Iron-Mediated Allylic Substitution Reactions with Chirality Transfer. Stereochemistry of the Formation of Diastereo- and Enantiomerically Enriched Olefinic and Allylic Tetracarbonyl Iron Complexes

Mechanism of palmitoleic acid oxidation into volatile compounds during heating

First Total Synthesis and Determination of the Absolute Configuration of the Stress Factor (+)-Hydroxymyoporone

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