Retigeranic Acid Research Articles

First Synthesis of (±)-Retigeranic Acid

First Synthesis of (±)-Retigeranic Acid

Total Synthesis of Complex Sesterterpene Retigeranic Acid A

Total Synthesis of Complex Sesterterpene Retigeranic Acid A

Total Synthesis of (–)-Retigeranic Acid A

Total Synthesis of (–)-Retigeranic Acid A

Synthesis of (–)-Retigeranic Acid A

Synthesis of (–)-Retigeranic Acid A

Enantiocontrolled Total Synthesis of (-)-Retigeranic Acid A.

The asymmetric total synthesis of (-)-retigeranic acid A has been realized. The key features of the current synthesis include (1) a Pt-catalyzed Conia-ene 5-exo-dig cyclization of enolyne to establish the key quaternary stereochemical center of C-10 (D/E ring), (2) an intramolecular diastereoselective Prins cyclization to construct the trans-hydrindane backbone (A/B ring), and (3) a late-stage intramolecular Fe-mediated hydrogen atom transfer (HAT) Baldwin-disfavored 5-endo-trig radical cyclization to rapidly assemble vicinal quaternary centers and the core structure of (-)-retigeranic acid A (C ring).

Total Synthesis of (-)-Retigeranic Acid A: A Reductive Skeletal Rearrangement Strategy.

The asymmetric total synthesis of (-)-retigeranic acid A was described, which relies on a crucial reductive skeletal rearrangement cascade for the controllable assembly of diverse angular triquinane subunits. Taken together with an intramolecular Michael/aldol cyclization, an ODI-[5 + 2] cycloaddition/pinacol rearrangement cascade, a Wolff ring contraction and a stereoselective HAT reduction, our synthetic approach has enabled the access to (-)-retigeranic acid A in a concise and practical manner.

A Synthetic Route to The Core Structure of (-)-Retigeranic Acid A.

Retigeranic acid A is a uniquely structured pentacyclic sesterterpene bearing eight stereogenic centers. We report a concise route to the core structure of (-)-retigeranic acid A. The stereochemistry of its six chiral centers and three quaternary carbon centers was well-controlled. This route features two intramolecular Pauson-Khand reactions (IMPKRs): the first forged the D and E rings to deliver the triquinane subunit, and the second constructed the A and B rings and diastereoselectively installed the quaternary C6a center.

Enantioselective Conversion of Achiral Cyclohexadienones to Chiral Cyclohexenones by Desymmetrization.

The enantioselective reduction of prochiral 4,4-disubstituted 2,5-cyclohexadienones to chiral 2-cyclohexenones has been accomplished by the use of a carefully selected chiral bisphosphine-CuI complex and diisobutylaluminum hydride-hexamethylphosphoric triamide complex. This reagent has provided access to a key bicyclic intermediate for the total synthesis of the natural enantiomer of the pentacyclic sesterterpene retigeranic acid that involves spatial discrimination between CH3 and CH2CH2R substituents, an operation that has been elusive previously. In addition, a second method for desymmetrization is described using catalytic enantioselective [4 + 2]-cycloaddition of cyclopentadiene to prochiral 4,4-disubstituted 2,5-cyclohexadienones.

ChemInform Abstract: Diastereoselective Synthesis of Cyclopentanoids: Applications to the Construction of the ABCD Tetracyclic Core of Retigeranic Acid A.

AbstractThe key steps are a novel Rh‐catalyzed [3+2] cycloaddition of enyol (II) for the construction of the cyclopentanoid having two contiguous quaternary stereocenters at the bridgehead positions and the intramolecular Pauson—Khand reaction affording the advanced tetracyclic core structure of retigeranic acid A.

Diastereoselective synthesis of cyclopentanoids: applications to the construction of the ABCD tetracyclic core of retigeranic acid A.

A concise and efficient approach for the construction of the tetracyclic carbon skeleton of retigeranic acid A is described. The key transformations include a novel Rh-catalyzed [3+2] cycloaddition of enyol to afford cyclopentanoid E, bearing two contiguous quaternary stereocenters at the bridgehead positions, and an intramolecular Pauson-Khand reaction to construct the advanced tetracyclic core structure of retigeranic acid A.

Phylogenetic analysis indicates transitions from vegetative to sexual reproduction in theLobaria retigeragroup (Lecanoromycetidae, Ascomycota)

AbstractPhylogenetic relationships among the hypothetical species pairsLobaria kurokawae/L. retigeraandL. pseudopulmonaria/L. isidiosawere investigated based on TLC techniques and the phylogenetic analysis of the internal transcribed spacers (ITS) nrDNA. Results of TLC demonstrate thatL. retigeraandL. kurokawaecan be chemically distinguished fromL. isidiosaandL. pseudopulmonariaby the absence of retigeranic acid. Parsimony analysis of 18 specimens shows two monophyletic clades – aL.retigeralineage and aL. isidiosalineage—both including their apotheciate counterparts. Unlike the original hypothesis of species pairs, our study reveals transitions from isidiate morphs that have the potential to rarely form apothecia, towards apotheciate morphs that produce no vegetative propagules.

Structure and absolute stereochemistry of fusaproliferin, a toxic metabolite from Fusarium proliferatum.

Fusaproliferin is a toxic sesterterpene isolated from Fusarium proliferatum, a widespread pathogen of cereals. Its absolute configuration has been determined by single crystal X-ray diffraction analysis. Fusaproliferin is considered to be a sesterterpene with a new ring skeleton having four C = C double bonds and four chiral atoms. The configurations of the four chiral atoms C10, C14, C15, and C19 are (R), (S), (R), and (S), respectively. In the solid state the macrolide shows a concave hydrophobic surface and hydrophilic convex face. The absolute configuration of C14 and C15 is the same as that observed for retigeranic acid, consistent with fusaproliferin being formed via a sesterterpenic-type biosynthetic pathway.

Further Studies on the Structure of Retigeranic Acid.

Retigeranic acid, C25H38O2, a sesterterpene isolated from the lichen, Lobaria retigera group, L. isidiosa VAIN. var. subisidiosa ASAH., was separated by high performance liquid chromatography into two components, retigeranic acid A (minor) (1) and B (major) (2). Crystals of both components were subjected to X-ray crystallographic analysis. The crystal parameters are monoclinic space group P21, Z=4 with a=24.10(3), b=12.86(1), c=7.412(9) A, β=96.5(1)° for 1 and a=24.067(17), b=12.614(9), c=7.457(5) A, β=96.30(7)° for 2.Retigeranic acids A and B were proved to be S and R stereoisomers at C-18, respectively. The absolute configurations of other parts of the structure of retigeranic acids are assumed to be identical, as they have previously been determined by the X-ray anomalous dispersion method on the p-bromoanilide derived from native retigeranic acid.

Convergent synthesis of the tetracyclic bcde structural fragment of retigeranic acid

A two-step synthesis was proposed for the tetracyclic triquinane bis-enone from two monocyclic precursors. The bis-enone obtained is a structural fragment of retigeranic acid.

Synthetic studies on arene-olefin cycloadditions. 11. Total synthesis of (−)-retigeranic acid

A convergent synthesis of (−)-retigeranic acid is described which is based on a Diels-Alder and arene-alkene cycloaddition strategy.

Arene-alkene cycloadditions and organic synthesis

Abstract

ChemInform Abstract: (2 + 3) and (3 + 4) Anellation of Enones. Enantiocontrolled Total Synthesis of (‐)‐Retigeranic Acid.

AbstractThe lithium dienolates of ethyl 2‐bromocrotonate (II) and of various other, more highly substituted α‐bromocrotonates undergo smooth additions to enones such as (I) to give the vinylcyclopropanes (III) and (IV) as endo/exo‐mixtures.

The [2 + 3] and [3 + 4] annulation of enones. Enantiocontrolled total synthesis of (-)-retigeranic acid [Erratum to document cited in CA111(11):97589v

The [2 + 3] and [3 + 4] annulation of enones. Enantiocontrolled total synthesis of (-)-retigeranic acid [Erratum to document cited in CA111(11):97589v

An expeditious route to the northern part of retigeranic acid A from (R)-(-)-Carvone

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn expeditious route to the northern part of retigeranic acid A from (R)-(-)-CarvoneJose Manuel Llera and Bert Fraser-ReidCite this: J. Org. Chem. 1989, 54, 23, 5544–5548Publication Date (Print):November 1, 1989Publication History Published online1 May 2002Published inissue 1 November 1989https://doi.org/10.1021/jo00284a029RIGHTS & PERMISSIONSArticle Views599Altmetric-Citations26LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (569 KB) Get e-Alerts Get e-Alerts

The [2 + 3] and [3 + 4] annulation of enones. Enantiocontrolled total synthesis of (-)-retigeranic acid

La reaction de cyclenes-2ones avec des bromocrotonates donne en une etape les vinylcyclopropanes corespondants. Ces derniers subissent differentes transpositions et fournissent des derives pentaleno dioxole, des bicyclo [3.3.0] octene-1, des bicyclo [4.3.0] nonene-7, des bicyclo [5.3.0] decene-8 ― carboxylates d'ethyle. Application a la synthese de l'acide retigeranique