Stereoselective Total Syntheses of C18-Oxo Eburnamine-Vincamine Alkaloids

Organic Letters, Journal Year: 2022, Volume and Issue: 24(12), P. 2409 - 2413

Published: March 21, 2022

Here, we disclose the divergent total syntheses of representative C18-oxo eburnamine-vincamine alkaloids (+)-eburnaminol, (−)-larutenine, and (−)-cuanzine. Key to approach is a substrate-controlled iridium-catalyzed asymmetric hydrogenation/lactamization cascade that leads formation common tetracyclic skeleton with essential cis-C20/C21 stereochemistry (93% yield, 98% ee, >20:1 dr, gram scale). Access targeted effected late in synthesis by implementation number diversity-oriented transformations late-stage modifications.

Language: Английский

---

Strategy to Construct Polycyclic Scaffolds via Formal Aza‐Diels‐Alder Reaction of Dihydro‐β‐Carboline with Heterodiene Precursor

Advanced Synthesis & Catalysis, Journal Year: 2023, Volume and Issue: 365(22), P. 3996 - 4001

Published: July 8, 2023

Abstract The formal aza‐Diels‐Alder reaction of dihydro‐ β ‐carboline with heterodiene mediated by caesium carbonate has been described. This pathway provided a mild approach to functionalized polycyclic frameworks in 41%–91% yields.

Language: Английский

---

A de novo synthesis of the bisindole alkaloid geissolosimine: collective synthesis of geissoschizoline, akuammicine, (16S)-deshydroxymethylstemmadenine and Aspidospermatan alkaloids

Organic Chemistry Frontiers, Journal Year: 2023, Volume and Issue: 11(3), P. 703 - 708

Published: Dec. 4, 2023

Collective synthesis of geissolosimine, geissoschizoline, akuammicine, (16 S )-deshydroxymethylstemmadenine and Aspidospermatan alkaloids was achieved based on a catalytic asymmetric double Michael addition.

Language: Английский

---

Regioselective Decarboxylative Transformations of Tetrahydro-β-carboline-1-carboxylic Acid: Reagent Controlled Selectivity toward Alkynylated or Enaminone Products

Organic Letters, Journal Year: 2023, Volume and Issue: 25(40), P. 7310 - 7315

Published: Oct. 4, 2023

A one-pot, regioselective decarboxylative alkynylation of tetrahydro-β-carboline-1-carboxylic acid under peroxide-free condition is reported. The reaction highly selective for the 1-position over 3-position tetrahydro-β-carboline. can afford alkynylated or enaminone products depending on reagent. proceeds through sequential iminium ion formation followed by an and oxidative rearrangement cascade.

Language: Английский

---

The crystal structure of (1S,3R)-1-(4-isopropylphenyl)-3-(methoxycarbonyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-2-iumchloride monohydrate, C₂₂H₂₇ClN₂O₃

Zeitschrift für Kristallographie - New Crystal Structures, Journal Year: 2022, Volume and Issue: 237(4), P. 619 - 621

Published: May 4, 2022

Abstract C 22 H 27 ClN 2 O 3 , orthorhombic, P 1 (no. 19), a = 8.6797(3) Å, b 9.8809(3) c 24.7824(8) V 2125.42(12) Å Z 4, R gt ( F ) 0.0478, wR ref 0.1082, T 170 K.

Language: Английский

---

Iridium‐Catalyzed Reductive (3+2) Annulation of Lactams Enabling the Rapid Total Synthesis of (±)‐Eburnamonine

Angewandte Chemie, Journal Year: 2023, Volume and Issue: 136(6)

Published: Dec. 13, 2023

Abstract A reductive (3+2) annulation of lactams through iridium‐catalyzed hydrosilylation and photoredox coupling with α‐bromoacetic acid was developed. The the lactam carbonyl group subsequent elimination provide a transient cyclic enamine, which undergoes in one‐pot process. developed conditions show high functional‐group tolerance N , O ‐acetals containing quaternary carbon center. resulting undergo variety acid‐mediated nucleophilic addition reactions via iminium ions to give substituted amines. sequence including successfully applied four‐step total synthesis (±)‐eburnamonine.

Language: Английский

---

Asymmetric Total Synthesis of Alstrostine G Utilizing a Catalytic Asymmetric Desymmetrization Strategy

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(34)

Published: May 31, 2024

Abstract A highly effective enantioselective monobenzoylation of 1,3‐diols has been developed for the synthesis 1,1‐disubstituted tetrahydro‐β‐carbolines. The chemistry successfully applied to asymmetric total (+)‐alstrostine G, which also features a cascade Heck/hemiamination reaction enabling facile construction pivotal pentacyclic core.

Language: Английский

---

Stereodivergent Total Synthesis of Tacaman Alkaloids

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(38)

Published: July 1, 2024

This paper describes a concise, asymmetric and stereodivergent total synthesis of tacaman alkaloids. A key step in this is the biocatalytic Baeyer-Villiger oxidation cyclohexanone, which was developed to produce seven-membered lactones establish required stereochemistry at C14 position (92 % yield, 99 ee, 500 mg scale). Cis- trans-tetracyclic indoloquinolizidine scaffolds were rapidly synthesized through an acid-triggered, tunable acyl-Pictet-Spengler type cyclization cascade, serving as pivotal reaction for building alkaloid skeleton. Computational results revealed that hydrogen bonding crucial stabilizing intermediates inducing different addition reactions during cascade. By strategically using these two late-stage diversification functionalized core, syntheses eight alkaloids achieved. study may potentially advance research related medicinal chemistry

Language: Английский

---

Stereodivergent Total Synthesis of Tacaman Alkaloids

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(38)

Published: July 1, 2024

Abstract This paper describes a concise, asymmetric and stereodivergent total synthesis of tacaman alkaloids. A key step in this is the biocatalytic Baeyer–Villiger oxidation cyclohexanone, which was developed to produce seven‐membered lactones establish required stereochemistry at C14 position (92 % yield, 99 ee , 500 mg scale). Cis ‐ trans ‐tetracyclic indoloquinolizidine scaffolds were rapidly synthesized through an acid‐triggered, tunable acyl‐Pictet–Spengler type cyclization cascade, serving as pivotal reaction for building alkaloid skeleton. Computational results revealed that hydrogen bonding crucial stabilizing intermediates inducing different addition reactions during cascade. By strategically using these two late‐stage diversification functionalized core, syntheses eight alkaloids achieved. study may potentially advance research related medicinal chemistry

Language: Английский

---

Green Light Promoted Iridium(III)/Copper(I)‐Catalyzed Addition of Alkynes to Aziridinoquinoxalines Through the Intermediacy of Azomethine Ylides

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(12)

Published: Jan. 25, 2024

Abstract This manuscript describes the development of alkyne addition to aziridine moiety aziridinoquinoxalines using dual Ir(III)/Cu(I) catalytic system under green light‐emitting diode (LED) photolysis (λ max =525 nm). mild method features high levels chemo‐ and regioselectivity was used generate 30 highly functionalized substituted dihydroquinoxalines in 36–98 % yield. transformation also carried asymmetrically phthalazinamine‐based chiral ligand provide 9 products 96 : 4 86 14 e.r. The experimental quantum chemical explorations this reaction suggest a mechanism that involves Ir(III)‐catalyzed triplet energy transfer followed by ring‐opening ultimately leading formation azomethine ylide intermediates. These intermediates undergo sequential protonation/copper(I) acetylide products.

Language: Английский

---