Trends in carbazole synthesis – an update (2013–2023)

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 21(45), P. 8956 - 8974

Published: Jan. 1, 2023

This review discusses last decade's developments in carbazole synthesis. Aspects of selectivity and functional group tolerance are evaluated, as well the applicability such protocols towards total synthesis natural products.

Language: Английский

---

Iridium-Catalyzed Tandem Dehydrogenation/Hydroarylation Approach to Synthetically Versatile C2-Alkenyl N–H Indoles

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(5), P. 2872 - 2882

Published: Feb. 9, 2024

Readily available N-carbamoyl indolines can be converted into highly valuable 2-alkenyl and 2-alkyl indoles in a one-pot reaction, through an autotandem catalytic cascade promoted by iridium complex. The process entails dehydrogenation reaction initiated iridium-promoted C(sp3)–H activation, the addition of resulting indole to alkyne -or alkene-partner, spontaneous loss carbamoyl directing group. Interestingly, C2-alkenyl participate variety metal-catalyzed annulations C–H including formal [4 + 1] 2] cycloadditions, as well cross-dehydrogenative cyclizations, thus enabling divergent access collection functionally rich nitrogen-containing heterocycles.

Language: Английский

---

Development of Carbazole-Cored Organo-Photocatalyst for Visible Light-Driven Reductive Pinacol/Imino-Pinacol Coupling

Organic Letters, Journal Year: 2022, Volume and Issue: 24(49), P. 9001 - 9006

Published: Dec. 5, 2022

Benzoperylenocarbazole (BPC), a unique carbazole-based organophotocatalyst, is reported herein as potent organo-photoreductant. Lower excited state oxidation potential (−2.0 V vs SCE) and reasonable lifetime (4.61 ns) render BPC an effective photosensitizer. Under irradiation of blue light employing low catalyst loading (0.5 mol %), plethora vicinal diols diamines were synthesized in excellent yields through reductive coupling carbonyls imines, respectively. Insight about the electronic structure was obtained by DFT calculations.

Language: Английский

---

B(C₆F₅)₃-Catalyzed [4 + 2] Cyclization Strategy: Synthesis and Photophysical Properties of 5H-Naphtho[2,3-c]carbazole-8,13-dione Derivatives

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(5), P. 2703 - 2713

Published: Feb. 17, 2023

In this paper, a series of novel carbazolequinones were efficiently obtained by B(C6F5)3-catalyzed [4 + 2] cyclization reaction. This protocol not only had simple operation, broad substrate range, and high atomic economy, but also low catalyst loading avoided using metal catalysts. addition, we constructed diverse new carbazole-fused compounds under different reduction conditions. The results photophysical characterization showed that the structure derivatives significant impact on fluorescence properties.

Language: Английский

---

Reversed Allylation of 3‐Alkenyl Indoles Using Allyl Boronic Acids: Access to Tryptamine Based Alkaloids

Chemistry - A European Journal, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 2, 2025

Abstract All‐carbon quaternary and tertiary stereocenters connected at the C2‐position of functionalizable C3‐alkylated indole nucleus are commonly occurring frameworks found in many alkaloids medicinal importance. Their direct access is scarcely reported, a long‐standing problem, developing unique yet simple method can pave pathway to an entirely different retrosynthetic route for total synthesis these alkaloids. Herein, this problem addressed by unprecedented branch‐selective allylation strategy employing broad range structurally electronically 3‐alkenyl‐indoles allylboronic acids. The use readily accessible starting precursors renders attractive present shows excellent functional group tolerance, atom economic, redox‐neutral, scalable easy operate. DFT calculation on possible transition states indicated that acid acts as nucleophile rather than more reactive boroxine. Mechanistically, designed exploiting loss well regaining indole's aromaticity. utility demonstrated syntheses seven prenylated tryptamine first dimeric alkaloids, fluevirine E mucronatin B.

Language: Английский

---

One-Flask, Telescoped Synthesis of Pyrano[3,2-b]indol-2-ones from O-Nitroynones and β-Ketoesters: Further Advancement to Functionalized Carbazoles

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: March 19, 2025

A new general strategy for accessing pyrano[3,2-b]indol-2-ones, a promising fused hybrid heterocyclic system, has been devised from o-nitroynones and β-ketoesters through one-flask cascade process involving tandem Michael addition, intramolecular cyclization, Cadogan-Sundberg reductive cyclization. The utility of this approach further amplified by leveraging the cycloaddition proclivity α-pyrone moiety in pyrano[3,2-b]indol-2-ones toward concise entry to carbazoles. Illustrative synthesis carbazole natural products hyellazole chlorohyellazole is also disclosed.

Language: Английский

---

Deprotonative Generation and Trapping of Haloaryllithium in a Batch Reactor

Organic Letters, Journal Year: 2023, Volume and Issue: 25(17), P. 3013 - 3017

Published: April 21, 2023

A method for the regioselective functionalization of haloarenes through deprotonative lithiation is disclosed. The generated haloaryllithiums were trapped in a batch reactor with zinc chloride diamine complex to provide organozinc species without aryne formation, which reacted electrophiles afford corresponding products 38-98% yields. This was applied five-step total synthesis carbazomycin on gram scale 33% overall yield.

Language: Английский

---

Photoredox/Palladium Dual Catalysis for Site-Selective C–H Arylation and Acylation of N-Protected Carbazoles in Visible Light

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(13), P. 8600 - 8608

Published: June 16, 2023

An unprecedented C-1 selective mono-arylation/acylation of N-protected carbazoles with aryl diazonium salts/glyoxylic acids has been developed in visible light by dual catalytic system comprising Eosin Y and palladium acetate. The methodology good functional group tolerance high regioselectivity furnishes the monosubstituted products moderate to yields at room temperature.

Language: Английский

---

Construction of C2-indolyl-quaternary centers by branch-selective allylation: enabling concise total synthesis of the (±)-mersicarpine alkaloid

Chemical Science, Journal Year: 2023, Volume and Issue: 15(5), P. 1789 - 1795

Published: Dec. 18, 2023

Herein we report a branch-selective allylation strategy for accessing C2-indolyl-all-carbon quaternary centers using allylboronic acids and implemented this method the total synthesis of mersicarpine alkaloid.

Language: Английский

---

An approach to functionalized carbazoles from Z-enoate propargylic alcohols. A unified total synthesis of N-Me-carazostatin, N-Me-carbazoquinocin C and N-Me-lipocarbazole A4

Chemical Communications, Journal Year: 2022, Volume and Issue: 58(73), P. 10210 - 10213

Published: Jan. 1, 2022

Development of an acid catalyzed, intramolecular benzannulation indoles for the synthesis functionalized carbazoles has been reported. The indole appended Z-enoate propargylic alcohols have employed. N-EDG-indoles involve 5-exo-dig cyclization followed by 1,2-migration to give carbazole-butenoates, whereas N-EWG-indoles undergo assisted Meyer-Schuster rearrangement dihydrocarbazole-4-oxo-butanoates. Utilizing one 2-methyl-carbazole-butyraldehyde (obtained from corresponding carbazole-butanoate) as key intermediate, we developed a simple approach efficient N-Me-carazostatin, N-Me-carbazoquinocin C and N-Me-lipocarbazole A4.

Language: Английский

---