Formal Synthesis of (−)-Haliclonin A: Stereoselective Construction of an Azabicyclo[3.3.1]nonane Ring System by a Tandem Radical Reaction

Komine, Keita; Urayama, Yasuhiro; Hosaka, Taku; Yamashita, Yūki; Fukuda, Hayato; Hatakeyama, Susumi; Ishihara, Jun

doi:10.1021/acs.orglett.0c01627

Cited by 15 publications

(14 citation statements)

References 28 publications

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“…The allylation of nucleophilic carbon centers is one of the most useful methods for the formation of C(sp 3 )-C(sp 3 ) linkages [3][4][5][6][7][8] . As a result, it has been widely applied in the synthesis of bioactive compounds and natural products [9][10][11][12][13][14][15] . For decades, tremendous effort has been devoted to developing new and efficient methods for allylic alkylation.…”

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confidence: 99%

Transition-metal-free allylation of 2-azaallyls with allyl ethers through polar and radical mechanisms

et al. 2021

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Allylation of nucleophiles with highly reactive electrophiles like allyl halides can be conducted without metal catalysts. Less reactive electrophiles, such as allyl esters and carbonates, usually require a transition metal catalyst to facilitate the allylation. Herein, we report a unique transition-metal-free allylation strategy with allyl ether electrophiles. Reaction of a host of allyl ethers with 2-azaallyl anions delivers valuable homoallylic amine derivatives (up to 92%), which are significant in the pharmaceutical industry. Interestingly, no deprotonative isomerization or cyclization of the products were observed. The potential synthetic utility and ease of operation is demonstrated by a gram scale telescoped preparation of a homoallylic amine. In addition, mechanistic studies provide insight into these C(sp3)–C(sp3) bond-forming reactions.

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confidence: 99%

Transition-metal-free allylation of 2-azaallyls with allyl ethers through polar and radical mechanisms

et al. 2021

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“…[1][2][3] A growing repertoire of selenium-containing small molecules have been employed as catalysts, ligands, and unconventional synthetic intermediates for the construction of complex structures. For example, the total syntheses of lycorine, [4] (À )-galanthamine, [5] (+)-deoxypancratistatin, [6] (À )-haliclonin A [7] rely on the use of organoselenium chemistry. The redox chemistry of oganoselenium compounds has been widely exploited to develop an array of seleniummediated oxidative functional group interconversions.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Applications of Organic Selenols

Tanini

Capperucci

2021

Adv Synth Catal

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The synthesis and the study of organoselenium compounds have received much attention over the past decades. Selenium-containing organic molecules are widely used in organic synthesis, materials science, and medicinal chemistry. Selenium -and more specifically the amino acid selenocysteine, bearing a selenol (SeH) moiety -is present in at least 25 human protein families, whose biological functions have not been completely identified. Amongst the variety of organoselenium compounds, selenols are a versatile class of molecules easily undergoing a broad array of useful transformations. Because of the unique properties of the SeH group, selenol chemistry has important applications in chemical sciences, spanning from organic synthesis to materials chemistry and biology. This review summarises currently available methodologies for the synthesis of selenols and highlights applications of selenols in chemical sciences and biology. Conclusions and Outlook 5.1. Safety Measures

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“…[1][2][3] For example, Ishihara and co-workers constructed the azabicyclo [3.3.1]nonane core of (À )-haliclonin A through an elegant stereoselective tandem radical reaction of a key selenocarbamate precursor with allyltributylstannane. [4] Selenocarbamates undergo palladium-catalysed insertion of isocyanides into the carbon-selenium bond providing amino-2-oxoethanimidoselenoates. [5] The palladium-catalysed reaction of selenocarbamates with alkynes was exploited for the regio-and stereoselective synthesis of β-selenoacrylamides.…”

Section: Introductionmentioning

confidence: 99%

Click Reaction of Selenols with Isocyanates: Rapid Access to Selenocarbamates as Peroxide‐Switchable Reservoir of Thiol‐Peroxidase‐Like Catalysts

et al. 2021

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Selenols react with isocyanates under mild catalyst-free conditions to generate selenocarbamates in good yield and with high selectivity over potentially competing nucleophilic additions. The methodology enables the incorporation of a wide variety of functional groups providing access to a broad array of densely functionalised selenocarbamates. In the presence of competing heteroatom-centered nucleophiles, isocyanates selectively couple with selenols. Selenocarbamates exhibited thiol-peroxidase-like properties, enabling the reduction of hydrogen peroxide at the expense of thiols, which are converted into the corresponding disulfides. A series of control experiments suggested that the catalytic mechanism proceeds through a pathway, involving a H 2 O 2 -promoted transcarbamoylation reaction leading to a thiocarbamate with concomitant releasing of catalytically active selenolate anions. By undergoing peroxide-driven thiol-selenol exchange, selenocarbamates behave as equivalents of selenolate anions with thiol-peroxidase-like activity.

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Formal Synthesis of (−)-Haliclonin A: Stereoselective Construction of an Azabicyclo[3.3.1]nonane Ring System by a Tandem Radical Reaction

Cited by 15 publications

References 28 publications

Transition-metal-free allylation of 2-azaallyls with allyl ethers through polar and radical mechanisms

Transition-metal-free allylation of 2-azaallyls with allyl ethers through polar and radical mechanisms

Synthesis and Applications of Organic Selenols

Click Reaction of Selenols with Isocyanates: Rapid Access to Selenocarbamates as Peroxide‐Switchable Reservoir of Thiol‐Peroxidase‐Like Catalysts

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