Syntheses of retipolide E and ornatipolide, 14-membered biaryl-ether macrolactones from mushrooms

Ingerl, Andrea; Justus, Karl; Hellwig, Veronika; Steglich, Wölfgang

doi:10.1016/j.tet.2007.03.022

Cited by 19 publications

(22 citation statements)

References 20 publications

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“…At this stage, the completion of the structural determination was prevented by strong line broadening of several 13 C NMR signals, [2] missing connectivities for the quaternary carbons in the 2D spectra, and the propensity of retipolide A to undergo decomposition.…”

Section: Retipolides a (1) And B (6)mentioning

confidence: 99%

“…The 1 H NMR spectrum of retipolide C exhibits only 18 of the expected 20 proton signals, suggesting the presence of two exchangeable protons as OH groups. In the 13 C NMR spectrum all 26 carbon signals are visible, which can be assigned to 4 methylene, 10 methine, and 12 quaternary carbons, three of the latter representing lactone carbons at δ C = 166.8, 167.1, and 168.5 ppm. Comparison with the 1 H and 13 C NMR spectra of the isomeric retipolide A (1) confirmed the presence of partial structure A (Figure 1).…”

Section: Retipolides a (1) And B (6)mentioning

confidence: 99%

“…Ring contraction of the oxepinone ring by an O/C-acyl shift could afford formylcyclopentenone 18, which should rearrange into the conjugated isomer 1a, the ring-opened form of retipolide A (1). The suggested precursor 16 could be formed by oxidative phenol coupling [10] of secoretipolide E (15), which could in turn be derived from butyrolactone II (13) [11] by transesterification with tyrosol (14). There is ample evidence that lactone 13 is formed in Aspergillus terreus from two units of 3-(4-hydroxyphenyl)pyruvic acid (12), a reaction that could be mimicked by treatment of methyl 3-(4-hydroxyphenyl)-pyruvate with aqueous Na 2 CO 3 [11b] or triethylamine.…”

Section: Biosynthetic Considerationsmentioning

confidence: 99%

“…[12] In order to test this proposal, we set out to isolate retipolide E (16) from the mushroom extract. For this purpose we synthesized retipolide E in both racemic and optically pure form [13] and studied its behavior on column chromatography and HPLC. Careful chromatography of the extract from R. retipes/ornatipes and collection of all fractions with the same R f value as the synthetic compound finally yielded a small amount of retipolide E (16), in every respect identical with the synthetic product, including optical rotation [α] D 20 = +83 and CD spectrum.…”

Section: Biosynthetic Considerationsmentioning

confidence: 99%

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Retipolides – Unusual Spiromacrolactones from the Mushrooms Retiboletus retipes and R. ornatipes

et al. 2007

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Mushrooms of the genus Retiboletus contain the retipolides A–D (1, 6–8), unusual 14‐membered spiromacrolides with a biphenyl ether linkage. The structures of these metabolites suggested a biogenetic sequence starting from retipolide E (16), which could furnish the unique 2(3H)‐oxepinone unit of retipolide C (7) via an oxidative enlargement of the 4‐hydroxyphenyl ring. A subsequent O/C‐acyl shift would then lead to the cyclopenta[c]pyran system of retipolide A (1). The proposed precursor 16 was synthesized and subsequently detected in the fungal extract in addition to the probable biosynthetic intermediates butyrolactone II (13), tyrosol (14), and secoretipolide E (15). The structural elucidation of retipolide A (1) was accomplished after transformation into a methoxyfulvene derivative 2a, and the absolute (R) configuration of 1 was assigned by a single‐crystal X‐ray analysis of the corresponding (S)‐sec‐butoxyfulvene analogue 2b. Some samples of R. retipes/ornatipes contained isoretipolide A (9), an isomer of 1 with a highly strained 12‐membered lactone ring incorporating two C,C‐coupled 4‐hydroxyphenyl units. A comparison of the CD spectrum of retipolide A (1) with those of the other retipolides and isoretipolide A (9) indicates that all of these macrolides possess R configuration. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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Section: Retipolides a (1) And B (6)mentioning

confidence: 99%

Section: Retipolides a (1) And B (6)mentioning

confidence: 99%

Section: Biosynthetic Considerationsmentioning

confidence: 99%

Section: Biosynthetic Considerationsmentioning

confidence: 99%

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Retipolides – Unusual Spiromacrolactones from the Mushrooms Retiboletus retipes and R. ornatipes

et al. 2007

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“…[44] [ Figure 1. Selected natural products with diaryl ether motif (for other natural products with diaryl ether motif see references [45][46][47][48][49][50] ).…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Natural Products on Solid Phases via Copper‐Mediated Coupling: Synthesis of the Aristogin Family, Spiraformin A, and Hernandial

Jung

Bräse

2009

Eur J Org Chem

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The formation of natural products on solid phases via diaryl ether coupling is presented herein. Starting with either commercially‐available or easily‐producible benzoic, cinnamic, or propionic acids, all immobilized on Merrifield resin via a pentane linker, copper‐mediated couplings yielded solid phase diaryl ethers in good yields. Both, phenol and resins containing aryl halides were used for these Ullmann‐type couplings to generate resin‐bound natural product derivatives. Through cleavage from the resin, eight naturally occurring substances isolated from Aristolochia elegans, Hernandia nymphaeifolia, Spiraea formosana, and Kandelia candel were prepared. To the best of our knowledge, four of these compounds, namely Aristogin D and F as well as Spiraformin A and compound 12 have never previously been synthesized. Gaining access to these natural products on solid supports, demonstrated the utility of diaryl ether formation for the development of combinatorial syntheses. Our approach to diaryl ethers on solid support offers the possibility of synthesizing libraries of natural product derivatives via combinatorial syntheses. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Boron Triiodide

Ronald

Karatholuvhu

2009

Encyclopedia of Reagents for Organic Synthesis

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Syntheses of retipolide E and ornatipolide, 14-membered biaryl-ether macrolactones from mushrooms

Cited by 19 publications

References 20 publications

Retipolides – Unusual Spiromacrolactones from the Mushrooms Retiboletus retipes and R. ornatipes

Retipolides – Unusual Spiromacrolactones from the Mushrooms Retiboletus retipes and R. ornatipes

Synthesis of Natural Products on Solid Phases via Copper‐Mediated Coupling: Synthesis of the Aristogin Family, Spiraformin A, and Hernandial

Boron Triiodide

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