Asymmetric Synthesis of Nidulalin A and Nidulaxanthone A: Selective Carbonyl Desaturation Using an Oxoammonium Salt DOI Creative Commons
Kaijie Ji, Richard P. Johnson, James McNeely

et al.

Published: Jan. 10, 2024

Nidulaxanthone A is a dimeric, dihydroxanthone natural product which was isolated in 2020 from Aspergillus sp. Structur-ally, the compound features an unprecedented heptacyclic 6/6/6/6/6/6/6 ring system unusual for xanthone dimers. Biosynthetically, nidulaxanthone originates monomer nidulalin via stereoselective Diels-Alder dimeri-zation. To expedite synthesis of and study proposed dimerization, we developed methodology involving use allyl triflate chromone ester activation followed by vinylogous addition to rapidly forge scaffold four-step sequence also ketone desaturation using Bobbitt’s oxoammonium salt. The asymmetric achieved acylative kinetic resolution (AKR) chiral, racemic 2H-nidulalin A. Dimerization en-antioenriched solvent-free, thermolytic conditions. Computational studies have been conducted probe both (4+2) dimerization events.

Language: Английский

Organic Synthesis Using Nitroxides DOI
Dirk Leifert, Armido Studer

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(16), P. 10302 - 10380

Published: Aug. 14, 2023

Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R1R2N–O•. The spin distribution over nitroxide N and O atoms contributes to thermodynamic stability of these radicals. presence bulky N-substituents R1 R2 prevents radical dimerization, ensuring their kinetic stability. Despite reactivity toward various transient C some nitroxides can be easily stored under air at room temperature. Furthermore, oxidized oxoammonium salts (R1R2N═O+) reduced anions (R1R2N–O–), enabling them act valuable oxidants reductants depending on oxidation state. Therefore, they exhibit interesting across all three states. Due fascinating properties, find extensive applications in diverse fields such biochemistry, medicinal chemistry, materials science, organic synthesis. This review focuses versatile For use other important fields, we will refer several articles. introductory part provides a brief overview history chemistry. Subsequently, key methods for preparing discussed, followed by an examination structural diversity physical properties. main portion this is dedicated reactions, wherein parent corresponding serve active species. It demonstrated that functional groups (such alcohols, amines, enolates, alkanes among others) efficiently oxidized. These oxidations carried out using catalysts combination stoichiometric terminal oxidants. By reducing anions, become effective reagents intriguing Nitroxides possess ability selectively react making useful terminating cascade reactions forming alkoxyamines. Depending structure, alkoxyamines weak C–O bonds, allowing thermal generation through reversible bond cleavage. Such thermally generated participate transformations, discussed end review. application strategy natural product synthesis presented.

Language: Английский

Citations

74
Total Synthesis of (±)- and (−)-Daphnillonin B DOI

Yun-Peng Zou,

Zheng-Lin Lai,

Mengwei Zhang

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(20), P. 10998 - 11004

Published: May 11, 2023

The first total synthesis of (±)- and (-)-daphnillonin B, a daphnicyclidin-type alkaloid with new [7-6-5-7-5-5] A/B/C/D/E/F hexacyclic core, has been achieved. [6-5-7] B/C/D ring system was efficiently diastereoselectively constructed via mild type I intramolecular [5+2] cycloaddition, followed by Grubbs II catalyst-catalyzed radical cyclization. [5-5] fused E/F synthesized diastereoselective Pauson-Khand reaction. Notably, the synthetically challenging core reassembled unique Wagner-Meerwein-type rearrangement from [6-6-5-7-5-5] framework found in calyciphylline A-type Daphniphyllum alkaloids.

Language: Английский

Citations

24
Enantioselective Total Synthesis of (−)-Daphenylline DOI

Bing-Lu Wu,

Jian-Neng Yao,

Xiang-Xi Long

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(2), P. 1262 - 1268

Published: Jan. 5, 2024

A concise enantioselective total synthesis of (−)-daphenylline, a hexacyclic Daphniphyllum alkaloid with unique benzene ring, was achieved in 14 steps. The commences two chiral stereocenters, C2 and C18, readily installed via Carreira's Ir/amine dual-catalyzed allylation. allylic bridgehead amine 6 rapidly prepared through Wickens' photoredox-catalyzed hydrocarboxylation olefin CuBr2-catalyzed α-amination ketone. tetracycle 4 formed Pd-catalyzed reductive Heck reaction or, more concisely, by Krische's Rh-catalyzed 1,6-enyne cyclization. In this synthesis, newly reported used twice, Friedel–Crafts acylation thrice.

Language: Английский

Citations

11
Total Synthesis of Four Classes of Daphniphyllum Alkaloids DOI
Wenhao Zhang,

Ming Lü,

Lu Ren

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(49), P. 26569 - 26579

Published: Nov. 30, 2023

The macrodaphniphyllamine-type, calyciphylline A-type, daphnilongeranin and daphnicyclidin D-type alkaloids are four structurally related classes of Daphniphyllum alkaloids. On the basis a systematic analysis biogenetic network these classes, we developed synthetic strategies centered on C4–N C1–C8 bonds A, which took full advantage suitable substrates, reactions, pathways that altered from their counterparts in postulated network. Through this generalized biomimetic approach, achieved first synthesis 14 subfamilies.

Language: Английский

Citations

19
Asymmetric Synthesis of Nidulalin A and Nidulaxanthone A: Selective Carbonyl Desaturation Using an Oxoammonium Salt DOI
Kaijie Ji, Richard P. Johnson, James McNeely

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(7), P. 4892 - 4902

Published: Feb. 6, 2024

Nidulaxanthone A is a dimeric, dihydroxanthone natural product that was isolated in 2020 from

Language: Английский

Citations

7
Collective total synthesis of fusicoccane diterpenoids via Yu [5+2+1] cycloaddition and oxidative Nazarov cyclization DOI Creative Commons

Sujun Xie,

Yuye Chen, Yan Zhang

et al.

Cell Reports Physical Science, Journal Year: 2024, Volume and Issue: 5(3), P. 101855 - 101855

Published: March 1, 2024

The fusicoccane diterpenoids have triggered particular interest from the organic synthesis community in recent years, owing to their promising biological profiles and complex chemical structures. Here, we report collective, asymmetric total syntheses of five diterpenoids, namely fusicoauritone, fusicogigantones A B, fusicogigantepoxide, anadensin. This work features a Yu [5+2+1] cycloaddition that is shown be swift approach access [5,8]-bicyclic ring system an oxidative Nazarov cyclization facilely fabricated critical cyclopentenone moiety via unfunctionalized tertiary divinyl carbinol (TDC) substrate. substrate scope study also revealed general robust transformation capable synthesizing highly substituted cyclopentenones TDCs.

Language: Английский

Citations

7
Total Synthesis of Yuzurine-type Alkaloid Daphgraciline DOI
Lixuan Li, Long Min,

Tian-Bing Yao

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(41), P. 18823 - 18828

Published: Oct. 5, 2022

The first total synthesis of daphgraciline has been achieved, which also represents the example Daphniphyllum yuzurine-type alkaloids (∼50 members). unique bridged azabicyclo[4.3.1] ring system in subfamily was efficiently and diastereoselectively assembled via a mild type II [5+2] cycloaddition for time. compact tetracyclic [6-7-5-5] skeleton installed an intramolecular Diels-Alder reaction, followed by benzilic acid-type rearrangement. synthetically challenging spiro tetrahydropyran moiety final product TiIII-mediated reductive epoxide coupling reaction. Potential access to enantioenriched is presented.

Language: Английский

Citations

25
Divergent Total Syntheses of (−)‐Daphnezomines A and B and (+)‐Dapholdhamine B DOI

Shaobin Su,

Chengcheng Lin,

Hongbin Zhai

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(23)

Published: March 30, 2023

The daphnezomine A-type subfamily of Daphniphyllum alkaloids structurally features a unique aza-adamantane core skeleton and anticipates efficient strategies for completing their syntheses to thoroughly investigate biological activities. Herein, divergent total (-)-daphnezomines A B (+)-dapholdhamine have been accomplished in 16-20 steps from known epoxide via rapid construction common intermediate. present work Ti-mediated radical cyclization establish the azabicyclo[3.3.1]nonane ring system, an intramolecular Heck reaction install bridgehead all-carbon quaternary stereocenter, tandem deprotection/reduction/keto amine-carbinolamine tautomerization furnish backbone, NIS-promoted 6-endo-trig aminocyclization assemble backbone.

Language: Английский

Citations

15
Total Synthesis of Laurane and Guaiane Sesquiterpenoids via Oxidative Nazarov Reaction DOI
Yuye Chen, Wenqing Chen, Zhiting Zhang

et al.

Chinese Journal of Chemistry, Journal Year: 2024, Volume and Issue: 42(11), P. 1267 - 1274

Published: Feb. 19, 2024

Comprehensive Summary As one of the most common structural motifs in natural products, cyclopentenones usually can be fabricated by Nazarov cyclization using divinyl ketones or functionalized tertiary carbinols (TDCs) as substrates. However, straightforward method for transforming unfunctionalized TDCs to their corresponding is currently lacking. Herein, we wish report total syntheses four structurally distinct terpenoids, namely laurane‐type marine sesquiterpenoids isolaurene, debromoaplysin and aplysin, guaiane sesquiterpenoid guaiadienone A, all a novel synthetic method, named oxidative cyclization, key step. This work demonstrated our robust suitable synthesizing various highly substituted cyclopentenones.

Language: Английский

Citations

5
Asymmetric Photoinduced Excited-State Nazarov Reaction DOI

Xuelong Qiao,

Shaojun Zhai,

Jiwei Xu

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(42), P. 29150 - 29158

Published: Oct. 9, 2024

We report herein the first asymmetric photoinduced excited-state Nazarov reaction of non-aromatic dicyclic divinyl ketones by using hydrogen-bonding catalysis. The enantioselectivity electrocyclization is highly dependent on structural features substrate and its interaction with chiral catalysts. For simple ketone substrates, there no discernible selectivity hydrogen bond coordination between thiourea carbonyl groups substrates in ground state. However, we found that direction was well controlled each model

Language: Английский

Citations

4