Synthesis of the sporolide ring framework through a cascade sequence involving an intramolecular [4+2] cycloaddition reaction of an o-quinone.

Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Angewandte Chemie International Edition (Impact Factor: 11.34). 02/2008; 47(8):1432-5. DOI: 10.1002/anie.200705334
Source: PubMed
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    ABSTRACT: The total synthesis of the structurally unique secondary metabolite sporolide B (1b) is described. The total synthesis of 1b was developed on the basis of preliminary studies that revealed the reactivity of an appropriate o-quinone as a diene system toward a number of indene derivatives as dienophiles, first in intermolecular and thence intramolecular settings. Thus, substrates were devised (37 and 75) that underwent exquisite intramolecular [4+2] cycloaddition reactions under thermal conditions to provide primitive sporolide-type structures that were subsequently elaborated to a sporolide model system, 9-epi-sporolide B, and 1b. The requisite indene o-quinone precursor 75 was synthesized through a ruthenium-catalyzed [2+2+2] cycloaddition reaction between a propargylic alcohol and a chloroacetylenic cyclopentenyne, followed by elaboration and silver-promoted oxidation of the resulting chloroindene derivative. In addition to the total synthesis of 1b, this work demonstrated, for the first time, the power of the intramolecular hetero [4+2] cycloaddition reaction in the total synthesis of complex molecules and the application of the ruthenium-catalyzed [2+2+2] cycloaddition reaction to highly substituted indene systems possessing a chlorine residue on the aromatic nucleus.
    Journal of the American Chemical Society 08/2010; 132(32):11350-63. · 10.68 Impact Factor
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    ABSTRACT: Studies directed towards the synthesis of the architecturally complex marine natural product sporolide B are described. Synthetic analysis suggested advanced hydroquinone and benzodiquinane fragments, which upon elaboration were successfully united via an ester linkage. Macrocyclization studies were then carried out, and although a novel macrocyclization product was obtained, subsequent studies revealed that the tertiary hydroxyls at C(6) and C(10) were sterically encumbered to participate in a successful macrocyclization to furnish sporolide B.
    Tetrahedron 09/2011; 67(35):6697-6706. · 2.80 Impact Factor
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    ABSTRACT: The first synthesis of members of the sarcodonin family, phellodonin and sarcodonin ε, is reported herein. This verifies that the unprecedented and seemingly unstable N,N-dioxide-containing benzodioxazine framework can be constructed in the laboratory and lends further support to the proposed structures. The key step in the synthesis involves a biomimetic hetero-Diels-Alder reaction between a pyrazine N-oxide and an ortho-quinone.
    Organic Letters 04/2013; · 6.14 Impact Factor


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Jenia Podolsky