Palladium II promoted rearrangement of germacranolides. Synthesis of (+)-stoebenolide and (+)-dehydromelitensin

Barrero, Alejandro F.; Oltra, J. Enrique; Álvarez-Corral, Míriam

doi:10.1016/s0040-4039(97)10775-4

Cited by 31 publications

(25 citation statements)

References 14 publications

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“…However, apart from biological degradation of R-santonin, scant information about bioconversion of other sesquiterpene lactones was available. 3 Therefore, microbiological transformation of some accessible sesquiterpenoids (1)(2)(3)(4)(5)(6), which can be useful as raw materials for enantiospecific synthesis of bioactive lactones, was investigated using the fungi Cunninghamella echinulata and Rhizopus oryzae. The results from incubations with (+)-costunolide 4 (1), (+)-cnicin 5 (2), (-)-dehydrocostuslactone 6 (4), and (-)-lychnopholide 7 (5) are reported in this paper.…”

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Microbial Transformation of Sesquiterpene Lactones by the Fungi Cunninghamella echinulata and Rhizopus oryzae

et al. 1999

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Incubations of the fungi Cunninghamella echinulata and Rhizopus oryzae with the sesquiterpene lactones (+)-costunolide (1), (+)-cnicin (2), (+)-salonitenolide (3), (-)-dehydrocostuslactone (4), (-)-lychnopholide (5), and (-)-eremantholide C (6) were perfomed. Incubation of 1 with C. echinulata afforded ∆ 11(13)dihydrogenation and ∆ 1(10) -epoxidation products (7-10). C. echinulata also hydrolyzed the side chain of 2, and transformed 4 into (+)-11R,13-dihydrodehydrocostuslactone (12), a new natural product. R. oryzae converted 4 into both ∆ 11(13) -dihydrogenation and ∆ 10( 14) -epoxidation products (16 and 17). Both fungi transformed 5 into (-)-16-(1-methyl-1-propenyl)eremantholanolide ( 13), providing experimental evidence for the biosynthesis of the eremantholide hemiketal unit. Compounds 3 and 6 were not metabolized by either fungus under the test conditions.

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Microbial Transformation of Sesquiterpene Lactones by the Fungi Cunninghamella echinulata and Rhizopus oryzae

et al. 1999

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“…10 The Cope rearrangement of germacranolides to elemanolides has been investigated. 12 Eudesmanolides were also produced in this approach. The co-occurrence of elemanes, germacranes and eudesmanes in T. claussenii is a good evidence that the biogenetic pathway of these sesquiterpenoids involves a single precursor.…”

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confidence: 99%

“…12 We have already reported the isolation and identification of cycloartane triterpenoids from the leaves of T. claussenii.…”

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Terpenoids and Steroids from Trichilia Species

Pupo¹,

Adorno²,

Vieira³

et al. 2002

J. Braz. Chem. Soc.

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O trabalho descreve o isolamento de três novos sesquiterpenóides do extrato metanólico dos galhos de Trichilia claussenii: 14-hidroxielemol, germacra-10(14)-en-9,11,15-triol e germacra-3,10(14)-dien-9,11-diol-4-carbaldeído. Também foram isolados os sesquiterpenos β-eudesmol, criptomeridiol e o triterpeno 22,25-diidroxi-9β,19-ciclolanost-23-en-3-ona. Do extrato diclorometânico das folhas de T. lepidota foram isolados mistura de hidrocarbonetos (C 29 H 60 , C 31 H 64 e C 33 H 68 ), mistura dos sesquiterpenos epóxido de cariofileno e epóxido de humuleno, espatulenol e os esteróides 24-metileno-12β-hidroxicolesterol, 24-metil-12β-hidroxicolest-4-en-3-ona, 3-palmitato de 24-metil-12β-hidroxicolest-5-eno, mistura de 24-metilenocolesterol, campesterol, estigmasterol e β-sitosterol, além de α-tocoferol e fitol. O extrato metanólico forneceu a N-metil-4-hidroxiprolina. As estruturas das substâncias isoladas foram estabelecidas com base em dados espectroscópicos.The methanol extract of stems of Trichilia claussenii yielded three new sesquiterpenoids: 14-hydroxyelemol, germacra-10(14)-en-9,11,15-triol and germacra-3,10(14)-dien-9,11-diol-4-carbaldehyde. Two known sesquiterpenoids β-eudesmol, cryptomeridiol and the triterpenoid 22,25-dihydroxy-9β,19-cyclolanost-23-en-3-one were also isolated. The dichloromethane extract from the leaves of T. lepidota afforded a mixture of hydrocarbons (C 29 H 60 , C 31 H 64 and C 33 H 68 ), a mixture of the sesquiterpenes caryophyllene and humulene epoxides, spathulenol, and a series of sterols: 24-methylene-12β-hydroxycholesterol, 24-methyl-12β-hydroxycholest-4-en-3-one, 24-methylene-12β-hydroxycholest-5-ene-3-palmitate; a mixture of 24-methylenecholesterol, campesterol, stigmasterol and β-sitosterol; besides α-tocoferol and phytol. From the methanol extract it was isolated N-methyl-4-hydroxyproline. The structures of the isolated compounds were determined on the basis of spectroscopic analysis.

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“…A remarkable reaction of the germacrane sesquiterpenes is the [3,3] sigmatropic Cope rearrangement in which cyclodecadienes are thermally converted into 1,2-divinylcyclohexane. The existence of an equilibrium between (E,E)-germacradiene and trans-elemene sesquiterpenes has been widely reported and its position is influenced by several factors such as substitution pattern, ring strain, conformation and conjugation effects, [1] although it generally lies toward the elemane isomer.…”

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confidence: 99%

Rearrangement of Germacranolides. Synthesis and Absolute Configuration of Elemane and Heliangolane Derivatives from Cnicin

et al. 2003

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A study of the Cope rearrangement of 15‐oxo‐germacranolides to 15‐oxo‐elemanolides has been carried out. The synthesis of two natural elemanolides, isolated from Centaurea paui, and an efficent isomerization of the C‐4/C‐5 double bond of 15‐oxo‐germacranolides to form heliangolides are reported. The absolute configuration of all the compounds has been ascertained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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Palladium II promoted rearrangement of germacranolides. Synthesis of (+)-stoebenolide and (+)-dehydromelitensin

Cited by 31 publications

References 14 publications

Microbial Transformation of Sesquiterpene Lactones by the Fungi Cunninghamella echinulata and Rhizopus oryzae

Microbial Transformation of Sesquiterpene Lactones by the Fungi Cunninghamella echinulata and Rhizopus oryzae

Terpenoids and Steroids from Trichilia Species

Rearrangement of Germacranolides. Synthesis and Absolute Configuration of Elemane and Heliangolane Derivatives from Cnicin

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