Synthetic Approaches to Guanacastepenes. Enantiospecific Syntheses of BC and AB Ring Systems of Guanacastepenes and Rameswaralide

Srikrishna, A.; Dethe, Dattatraya H.

doi:10.1021/ol036057i

Cited by 48 publications

(20 citation statements)

References 31 publications

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“…More recently, the same group isolated eight new neodolastanes, named plicatilisins A-H (37)(38)(39)(40)(41)(42)(43)(44), from the fungi Coprinus plicatilis. 28,29 The relative conguration of plicatilisin A (37) was suggested from NOESY experiments and compared to published data for guanacastepene N (15).…”

Section: Structural Diversity Of Neodolastanesmentioning

confidence: 99%

The isolation and synthesis of neodolastane diterpenoids

et al. 2015

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The neodolastane diterpenoids comprise a group of 44 compounds including guanacastepenes, heptemerones, plicatilisins, radianspenes, 2,15-epoxy-5,13-dihydroxyneodolast-3-en-14-one and sphaerostanol. These fungal and marine natural products are characterized by a tricyclic neodolastane skeleton that consists of fused five-, seven- and six-membered rings. Their reported antibiotic activities against antibiotic-resistant bacteria together with strong antifungal and anticancer activities and their novel structures render these compounds interesting synthetic targets. The aim of this account is to summarise the progress in the isolation, characterisation and synthesis of these diterpenoids as well as to review their biogenetic origins and diverse biological activities since their discovery in 2000.

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Section: Structural Diversity Of Neodolastanesmentioning

confidence: 99%

The isolation and synthesis of neodolastane diterpenoids

et al. 2015

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“…Srikrishna and co-workers reported an asymmetric route to a 5-7 ring system similar to the AB-ring system present in guanacastepene A (Scheme 4). 15 Beginning from (R)-carvone, stepwise introduction of the methyl and allyl groups, respectively, gave compound 23. Further elaboration led to a,b-epoxy ketone 25.…”

Section: Hydroazulene Corementioning

confidence: 99%

Progress toward the Total Synthesis of Guanacastepene A

Maifeld¹,

Lee²

2006

Synlett

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P r o g r e s s t o w a r d t h eAbstract: Guanacastepene A, the leading member of a structurally diverse family of diterpene natural products, was isolated from the extracts of an unidentified fungus. The discovery of its potent antibiotic activity as well as its previously unreported tricyclic architecture render guanacastepene A an attractive and formidable target for total synthesis. Specifically, guanacastepene A's synthetic challenges include 2 ring-junction quaternary methyl groups and a novel 5-7-6 tricyclic carbon skeleton possessing a dense array of oxygen and unsaturated functionalities. In this account, we will discuss our motivation and efforts toward the total synthesis of guanacastepene A as well as highlight the contributions from the synthetic community toward this pursuit.

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“…The expected epoxide IV was not detected. Apparently epoxide IV originating from monomethyl derivative III and the other epoxy byproducts unlike compound I enolized under the reaction conditions and thus initiated intermolecular condensation processes involving compounds III and IV or led to the formation of more polar compounds of type VI through Faworsky intermediate V [15] (Scheme 3).…”

mentioning

confidence: 99%

Efficient synthesis of (1R,4S,6R)-4-Isopropenyl-1,3,3-trimethyl-7-oxabicyclo[4.1.0]heptan-2-one

et al. 2011

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A simple and convenient one-pot synthesis of (1R,4S,6R)-4-isopropenyl-1,3,3-trimethyl-7-oxabicyclo[4.1.0]heptan-2-one was developed consisting in a thermodynamic methylation of carvone (NaH, MeI, THF, 20°C) followed by the epoxidation with alkalinized hydrogen peroxide. The reduction of the obtained epoxyketone with sodium borohydride proceeded stereoselectively to give a β-alcohol. The attempts to convert its isopropenyl fragment into an acetate group by a rearrangement of products or intermediates of the oxidative fragmentation resulted only in obtaining intermediate acyl derivatives.

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Synthetic Approaches to Guanacastepenes. Enantiospecific Syntheses of BC and AB Ring Systems of Guanacastepenes and Rameswaralide

Abstract: [reaction: see text] A simple and efficient approach for the BC and AB ring systems of the novel diterpenes guanacastepenes and rameswaralide starting from the readily and abundantly available monoterpene (R)-carvone employing RCM reaction as the key step is described.

Cited by 48 publications

References 31 publications

The isolation and synthesis of neodolastane diterpenoids

The isolation and synthesis of neodolastane diterpenoids

Progress toward the Total Synthesis of Guanacastepene A

Efficient synthesis of (1R,4S,6R)-4-Isopropenyl-1,3,3-trimethyl-7-oxabicyclo[4.1.0]heptan-2-one

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