Stereoselective Synthesis of 4‐Dehydroxydiversonol Employing Enantioselective Palladium‐Catalysed Domino Reactions

Tietze, Lutz F.; Spiegl, Dirk A.; Stecker, Florian; Major, Julia; Raith, Christian; Große, Christian U.

doi:10.1002/chem.200800967

Cited by 68 publications

(36 citation statements)

References 49 publications

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“…[6] Nicolaou and Li confirmed the discrepancy between the NMR data and the structure thus assigned of b-diversonolic ester some 30 years ago, [7] which had already been reported by Krohn and co-workers. [8] Krohn and co-workers were the first to isolate a natural product named blennolide C from Blennoria sp., an endophytic fungus from Carpobrotus eduli.…”

supporting

confidence: 55%

Modular Syntheses of Diversonol‐Type Tetrahydroxanthone Mycotoxins: Blennolide C (epi‐Hemirugulotrosin A) and Analogues

Gérard¹,

Bräse²

2008

Chemistry A European J

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Mycotoxin synthesis: A versatile and modular synthesis of differently substituted tetrahydroxanthones is presented (see scheme). The core skeleton is obtained via a domino oxa‐Michael–aldol condensation reaction and allows access to these privileged structures in larger quantities. The synthetic approach has led to the total synthesis of blennolide C as well as to several advanced synthetic intermediates for the preparation of secalonic acids.

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supporting

confidence: 55%

Modular Syntheses of Diversonol‐Type Tetrahydroxanthone Mycotoxins: Blennolide C (epi‐Hemirugulotrosin A) and Analogues

Gérard¹,

Bräse²

2008

Chemistry A European J

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“…After cooling to rt, the reaction mixture was filtered through diatomaceous earth, and the filtrate was concentrated in vacuo. Chromatographic purification of the residue (hexanes:EtOAc 19:1) provided 12 60 as a clear oil (27 g, 89%): 1 H NMR (500 MHz, CDCl 3 ) δ 6.35 (d, J = 2.1 Hz, 2H), 6.31 (t, J = 2.2 Hz, 1H), 3.80, (s, 6H), 2.32 (s, 3H) ppm; 13 C NMR (125 MHz, CDCl 3 ) δ 160.9, 140.4, 107.3, 97.7, 66.1, 55.4, 22.0 ppm.…”

Section: Methodsmentioning

confidence: 99%

Total Synthesis of (+)-Nankakurines A and B and (±)-5-epi-Nankakurine A

et al. 2010

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The first total syntheses of the Lycopodium alkaloids (+)-nankakurine A (2), (+)-nankakurine B (3) and the originally purported structure 1 of nankakurine A were accomplished. The syntheses of 2 and 3 feature a demanding intramolecular azomethine imine cycloaddition as the key step for generating the octahydro-3,5-ethanoquinoline moiety and installing the correct relative configuration at the spiro piperidine ring juncture. The cyclization precursor was prepared from octahydronaphthalene ketone 50, which was assembled from enone (+)-9 and diene 48 by a cationic Diels–Alder reaction. The Diels–Alder reactants were synthesized from 5-hexyn-1-ol (16) and (+)-pulegone (49), respectively. The tetracyclic ring system of 1 was generated using an unprecedented nitrogen-terminated aza-Prins cyclization cascade. The enantioselective total syntheses of (+)-nankakurine A (2) and (+)-nankakurine B (3) establish the relative and absolute configuration of these alkaloids, and are sufficiently concise that substantial quantities of 2 and 3 were prepared for biological studies. (+)-Nankakurine A and (+)-nankakurine B showed no effect on neurite outgrowth in rat hippocampal H-19 cells over a concentration range of 0.3–10 μM.

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“…In this short overview of parts of our work, we would like to demonstrate the usefulness of multiple Pd-catalyzed transformations by presenting the enantioselective total synthesis of the contraceptive desogestrel (2) based on our synthesis of the natural steroid estradiol (1) [4,5], 4-dehydroxydiversonol (3) [6], where we used a similar approach as in the enantioselective synthesis α-tocopherol (4) [7], and molecular switches (5) (Scheme 1) [8].…”

Section: Introductionmentioning

confidence: 99%

Multiple Pd-catalyzed reactions in the synthesis of natural products, drugs, and materials

Tietze

Düfert

2010

Pure and Applied Chemistry

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The efficient synthesis of natural products, drugs, and materials with economical and ecological advantages is a very important goal in modern synthetic chemistry. In such an approach, toxic substrates as well as reagents have to be avoided, the amount of waste has to be reduced, and the exploitation of our resources has to be diminished. In this respect, the use of catalytic processes is highly advantageous; however, even more beneficial is the combination of several catalytic processes either in a sequential or, more efficiently, in a domino mode. In this article, the synthesis of several natural products, drugs, and materials is described, employing multiple Pd-catalyzed processes either in a sequential or a domino fashion. Based on a double-Heck reaction developed by us for the preparation of estradiol, the efficient synthesis of the highly potent contraceptive desogestrel is discussed; for the synthesis of α-tocopherol and diversonol an enantioselective domino-Wacker/Heck reaction was utilized, whereas in the case of diversonol, a domino-Wacker/carbonylation was even more effective, and several molecular switches containing a helical tetrasubstituted double bond were prepared employing a domino-carbopalladation/Stille reaction. Finally, acenaphthylenes could be obtained by a domino-carbopalladation/C-H-activation.

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Stereoselective Synthesis of 4‐Dehydroxydiversonol Employing Enantioselective Palladium‐Catalysed Domino Reactions

Cited by 68 publications

References 49 publications

Modular Syntheses of Diversonol‐Type Tetrahydroxanthone Mycotoxins: Blennolide C (epi‐Hemirugulotrosin A) and Analogues

Modular Syntheses of Diversonol‐Type Tetrahydroxanthone Mycotoxins: Blennolide C (epi‐Hemirugulotrosin A) and Analogues

Total Synthesis of (+)-Nankakurines A and B and (±)-5-epi-Nankakurine A

Multiple Pd-catalyzed reactions in the synthesis of natural products, drugs, and materials

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