Synthesis of (+)-Tacamonine via Stereoselective Radical Cyclization

Smith, Morton; Ferreira, Jasmin; Hunter, Roger; Venter, Gerhard A.; Su, Hong

doi:10.1021/acs.orglett.9b03308

Cited by 13 publications

(9 citation statements)

References 45 publications

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“…However, Mitsunobu inversion and methanolysis of 850 finalized the synthesis of another diastereomer 851 . In contrary, an asymmetric synthesis of the indole (+)‐tacamonine 857 (Scheme 134), an indole alkaloid with pentacyclic motif, isolated from Tabernaemontana eglandulosa was constructed by Hunter and co‐workers [315] . In this synthetic stratagem, CM was used to forge E ‐enoate 854 .…”

Section: Cross Metathesis (Cm)mentioning

confidence: 99%

“…In contrary, an asymmetric synthesis of the indole (+)-tacamonine 857 (Scheme 134), an indole alkaloid with pentacyclic motif, isolated from Tabernaemontana eglandulosa was constructed by Hunter and coworkers. [315] In this synthetic stratagem, CM was used to forge Eenoate 854. The acylation of chiral auxiliary 852 with butyryl chloride in presence of n-BuLi followed by NaHMDS-mediated alkylation with allyl bromide provided a terminal alkene 853, removal of chiral auxiliary from 853 with LiOH and H 2 O 2 generated a carboxylic acid, which effectively underwent to CM with ethyl acrylate in presence of HG-II catalyst 5 and furnished an enoate 854 in remarkable yield.…”

Section: Reviewmentioning

confidence: 99%

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Metathesis Reactions in Natural Product Fragments and Total Syntheses

et al. 2022

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The passion of total‐ and fragments syntheses of natural products always remained one of the top priorities among the synthetic chemists worldwide. Due their curiosity toward the complexity of molecules of living nature and their endeavour to imitate them in laboratory; limitless arrays of natural products have been extracted, architecturally‐elucidated, synthesized, and chronicled by utilizing various synthetic methodologies in different fashions. Frequently, the synthesis of complex natural products proceed with inscrutable synthetic challenges, which can be circumvented either by modification of previously developed synthetic methods or by formulating a new one. In this way, a myriad of powerful synthetic reactions have been developed since the genesis of the logic of chemical synthesis. Amongst them, metathesis tactics discovered unexpectedly in the 1950s (Nobel Prize in 2005), have incredibly influenced and changed the landscape of the art of the total and formal synthesis in the last three A. H. Hoveyda, A. R. Zhugralin, me abruptly as compared to other developed transformations or their modified forms. In this particular review article, we envisioned to report a comprehensive detail of the metathetic tools involved in both total and fragments synthesis of natural products in the years 2018 and 2019 along with an overview of 2017.

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Section: Cross Metathesis (Cm)mentioning

confidence: 99%

Section: Reviewmentioning

confidence: 99%

Metathesis Reactions in Natural Product Fragments and Total Syntheses

et al. 2022

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“…The first asymmetric total synthesis of haploscleridamine (24) was accomplished from histidine (Scheme 12) [126]. The synthesis starts with the tosylation of histidine methyl ester (152), then N-allylation with allyl bromide (154) The first total synthesis of the potential anticancer agent, the β-carboline-vasicinone hybrid alkaloid (±)-peharmaline A (25) was accomplished in a short sequence starting from readily available starting materials (Scheme 13) [127]. Boc-protected pyrrolidone 164 was reacted with acyl chloride 165 in the presence of LiHMDS.…”

Section: Co Mementioning

confidence: 99%

“…The first synthesis of (±)-tacamonine containing 3 stereocenters has been achieved by Massiot and co-workers [153]. Recently, the asymmetric synthesis of (+)-tacamonine (55) has been reported involving a stereoselective radical cyclization as the key step (Scheme 38) [154]. The synthesis starts from a commercially available oxazolidinone auxiliary (301) through an acylation followed by an allylation to form intermediate 302.…”

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confidence: 99%

Recent Advances in the Synthesis of β-Carboline Alkaloids

2021

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β-Carboline alkaloids are a remarkable family of natural and synthetic indole-containing heterocyclic compounds and they are widely distributed in nature. Recently, these alkaloids have been in the focus of interest, thanks to their diverse biological activities. Their pharmacological activity makes them desirable as sedative, anxiolytic, hypnotic, anticonvulsant, antitumor, antiviral, antiparasitic or antimicrobial drug candidates. The growing potential inherent in them encourages many researchers to address the challenges of the synthesis of natural products containing complex β-carboline frameworks. In this review, we describe the recent developments in the synthesis of β-carboline alkaloids and closely related derivatives through selected examples from the last 5 years. The focus is on the key steps with improved procedures and synthetic approaches. Furthermore the pharmacological potential of the alkaloids is also highlighted.

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“…Another example of an α‐phenylsulfanyl amide used as a radical cyclization precursor is found in Hunter's synthesis of (+)‐tacamonine (Scheme b). A key step was the radical cyclization of the tetrahydro β‐carboline 220 bearing a pendant α,β‐unaturated ester as the radical acceptor.…”

Section: 1‐azaalkyl‐centered Radical Precursorsmentioning

confidence: 99%

Radical Reactions in Alkaloid Synthesis: A Perspective from Carbon Radical Precursors

Bonjoch

Diaba

2020

Eur J Org Chem

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The usefulness of radical reactions in alkaloid synthesis is reviewed from the perspective of the functional groups embedded in the molecular structure of synthetic intermediates, that act as precursors of carbon‐centered radicals in the construction of new C–C bonds. The functional groups featured are alkenes, alkynes, halides (alkyl, vinyl, aryl), xanthates, sulfides, selenides, aldehydes, ketones, carboxylic acid derivatives (selenoesters, haloacetamides), β‐dicarbonyl compounds, and α‐heterosubstituted nitrogen‐compounds. The use of nitrogen‐centered radicals for C–N bond formation is also covered. Among the variety of radical processes applied, the most predominant are the hydride reductive method (Sn, Si), atom transfer radical reactions (Cu, Ru, B), and single‐electron transfer radical reactions promoted by Sm, Ni, Fe, Mn, Ti, and Ag. This review showcases the role radical reactions have played in the recent development of new strategies in alkaloid synthesis, as well as the implementation of new radical procedures in demanding substrates.

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Synthesis of (+)-Tacamonine via Stereoselective Radical Cyclization

Cited by 13 publications

References 45 publications

Metathesis Reactions in Natural Product Fragments and Total Syntheses

Metathesis Reactions in Natural Product Fragments and Total Syntheses

Recent Advances in the Synthesis of β-Carboline Alkaloids

Radical Reactions in Alkaloid Synthesis: A Perspective from Carbon Radical Precursors

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