An enantioselective synthesis and the absolute configuration of natural pumiliotoxin‐C. Preliminary communication

Oppolzer, Wolfgang; Flaskamp, Elmar

doi:10.1002/hlca.19770600123

Cited by 111 publications

(32 citation statements)

References 12 publications

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“…± Synthesis of Epilachnene. N-Tosylaziridine 11 was prepared in three steps from enantiomerically pure l-norvaline ((S)-2-aminopentanoic acid; 10) by a procedure adapted from the literature [6]. Nucleophilic substitution at the less-substituted C-atom of the aziridine ring with the cuprate derived from di(pent-4-enyl)magnesium proceeded in good yield 2 ).…”

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confidence: 99%

Synthesis of Macrocyclic Insect-Derived Alkaloids

Farmer

Schroeder

Meinwald

2000

HCA

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Dedicated to Professor Albert Eschenmoser on the occasion of his 75th birthday Macrocyclic lactonic alkaloids found in the pupal secretions of two species of a coccinellid beetle (genus Epilachna) were prepared in enantiomerically pure form via an efficient synthetic route using enantiomerically pure a-amino acids as chiral-pool starting materials. Macrocycles with rings containing up to 98 atoms were synthesized in good yield using Mukaiyamas macrolactonization conditions.Introduction. ± While natural-products chemistry is, by most criteria, a mature field, the chemical ecological approach to natural-products chemistry continues to uncover structural novelty among the pheromones, allomones, and kairomones that govern a very wide range of biologically significant interactions in nature. The macrocyclic alkaloids, the synthesis of which is the subject of this communication, were, in fact, discovered as the result of a biorational investigation.Since a pupating insect may be sessile for a period of up to a week or more, this stage in an insects life cycle manifests a heightened risk of predation. It is not surprising, therefore, that the pupae of many beetle species possess protection in various forms, most commonly spines or concealing coloration [1], but in some cases chemical defenses as well. The pupae of several species of ladybird beetle (family Coccinellidae) are coated with glandular hairs, the tips of which secrete droplets of a clear liquid that repels predators. Analysis of the defensive secretion exuded by pupae of the Mexican bean beetle Epilachna varivestis revealed it to consist principally of the macrocyclic lactone epilachnene ( (5Z)-11-propyl-12-azatetradec-5-en-14-olide (10Z)-5-propyl-1-oxa-4-azacyclopentadec-10-en-15-one; 1) along with minor amounts of related compounds [2]. Encouraged by this interesting result, we undertook the analysis of the pupal defensive alkaloids of related coccinellids and found that the pupa of Epilachna borealis (the squash beetle) is protected by a much more complex exudate consisting of a combinatorial library of very-large-ring oligomeric alkaloids [3].

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confidence: 99%

Synthesis of Macrocyclic Insect-Derived Alkaloids

Farmer

Schroeder

Meinwald

2000

HCA

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“…[15,16] Prominent examples in which aminodiene-based Diels-Alder reactions constitute attractive solutions for the formation of six-membered carbocycles with high regio-and stereoselectivity include the total syntheses of tabersonine, [17] gephyrotoxin, [18] dendrobine, [19] and pumiliotoxin C [20] (Scheme 2). [15,16] Prominent examples in which aminodiene-based Diels-Alder reactions constitute attractive solutions for the formation of six-membered carbocycles with high regio-and stereoselectivity include the total syntheses of tabersonine, [17] gephyrotoxin, [18] dendrobine, [19] and pumiliotoxin C [20] (Scheme 2).…”

Section: Chiral Dienamides In Diels-alder and Multicomponent Reactionsmentioning

confidence: 99%

In Situ Generation of ChiralN-Dienyl Lactams in a Multicomponent Reaction: An Efficient and Highly Selective Way to Asymmetric Amidocyclohexenes

et al. 2007

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Chiral N-dienyl lactams are crucial building blocks for the synthesis of complex organic compounds. However, their generation is rather challenging. This paper reports on a highly efficient and diastereoselective multicomponent methodology utilizing chiral amides, aldehydes, and dienophiles (AAD reaction). The three components readily react under in situ generation of chiral N-dienyl lactams which undergo a subsequent Diels-Alder reaction. Different chiral amides have been employed in the standard protocol delivering yields up to 94%, and selectivities up to 90% de. Moreover, DFT calculations were performed to explain the obtained selectivities.

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“…[8] Here, prominent examples include the total syntheses of pumiliotoxin C, [9] gephyrotoxin, [10] dendrobine, [11] and tabersonine. [12] More recently, we have been able to demon- strate the synthetic power of in situ-generated 1-amido-1,3-dienes for the synthesis of highly substituted anilines [13] and luminol derivatives.…”

Section: Introductionmentioning

confidence: 99%

Second Generation Protocol for Multicomponent Coupling Reactions of Aldehydes, Amides and Dienophiles

et al. 2004

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An improved one-pot procedure for the three-component coupling reaction of aldehydes, amides and dienophiles (AAD reaction) has been developed. Compared to known protocols for this type of reaction, the use of aromatic solvents in the presence of dehydrating reagents allows an efficient synthesis of previously not accessible products. Condensation of ubiquitous available aldehydes and amides and subsequent Diels±Alder reactions with dienophiles furnishes endo-selective amino-functionalized hexahydroisoindole-1,3-dione and tetrahydrophthalic acid derivatives in good yield.

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An enantioselective synthesis and the absolute configuration of natural pumiliotoxin‐C. Preliminary communication

Cited by 111 publications

References 12 publications

Synthesis of Macrocyclic Insect-Derived Alkaloids

Synthesis of Macrocyclic Insect-Derived Alkaloids

In Situ Generation of ChiralN-Dienyl Lactams in a Multicomponent Reaction: An Efficient and Highly Selective Way to Asymmetric Amidocyclohexenes

Second Generation Protocol for Multicomponent Coupling Reactions of Aldehydes, Amides and Dienophiles

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