Pyrrole and Its Derivatives

Mal, Dipakranjan; Shome, Brateen; Dinda, Bidyut Kumar

doi:10.1002/9783527634880.ch6

Cited by 34 publications

(16 citation statements)

References 98 publications

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“…Owing to a variety of disparate chemical architectures and often unique chemical reactivity, pyrrole-containing alkaloids have captivated practitioners of total synthesis for many decades . The high acid sensitivity and oxidative fragility inherent to electron-rich pyrroles, however, places many additional constraints on the employable tactics used to access these fascinating natural products .…”

Section: Introductionmentioning

confidence: 99%

Evolution of a Synthetic Strategy for Complex Polypyrrole Alkaloids: Total Syntheses of Curvulamine and Curindolizine

Xuan¹,

Haelsig²,

Шеремет³

et al. 2021

J. Am. Chem. Soc.

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Structurally unprecedented antibacterial alkaloids containing multiple electron-rich pyrrole units have recently been isolated from Curvularia sp. and Bipolaris maydis fungi. This article documents the evolution of a synthetic program aimed at accessing the flagship metabolites curvulamine and curindolizine which are presumably a dimer and trimer of a C 10 N biosynthetic building block, respectively. Starting with curvulamine, we detail several strategies to merge two simple, bioinspired fragments, which while ultimately unsuccessful, led us toward a pyrroloazepinone building block-based strategy and an improved synthesis of this 10π-aromatic heterocycle. A two-step annulation process was then designed to forge a conserved tetracyclic bis-pyrrole architecture and advanced into a variety of latestage intermediates; unfortunately, however, a failed decarboxylation thwarted the total synthesis of curvulamine. By tailoring our annulation precursors, success was ultimately found through the use of a cyanohydrin nucleophile which enabled a 10-step total synthesis of curvulamine. Attempts were then made to realize a biomimetic coupling of curvulamine with an additional C 10 N fragment to arrive at curindolizine, the most complex family member. Although unproductive, we developed a 14-step total synthesis of this alkaloid through an abiotic coupling approach. Throughout this work, effort was made to harness and exploit the innate reactivity of the pyrrole nucleus, an objective which has uncovered many interesting findings in the chemistry of this reactive heterocycle.

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Section: Introductionmentioning

confidence: 99%

Evolution of a Synthetic Strategy for Complex Polypyrrole Alkaloids: Total Syntheses of Curvulamine and Curindolizine

Xuan¹,

Haelsig²,

Шеремет³

et al. 2021

J. Am. Chem. Soc.

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“…Nitrogen-containing heterocycles are widely distributed in biologically active compounds [1][2][3][4]. Saturated nitrogen heterocycles such as pyrrolidines [5][6][7][8][9], piperidines, pyrrolizidines or indolizidines [10][11][12][13][14][15][16] are central fragments in various natural products, which are often synthesized from lactams by reduction.…”

Section: Introductionmentioning

confidence: 99%

α,γ-Dioxygenated amides via tandem Brook rearrangement/radical oxygenation reactions and their application to syntheses of γ-lactams

Klychnikov¹,

Pohl²,

Cı́sařová

et al. 2021

Beilstein J. Org. Chem.

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Pyrrolidones are common heterocyclic fragments in various biologically active compounds. Here, a two-step radical-based approach to γ-lactams bearing three to four stereocenters starting from epoxides, N-allylic silylacetamides and TEMPO is reported. The sequence starts with a new tandem nucleophilic substitution/Brook rearrangement/single electron transfer-induced radical oxygenation furnishing orthogonally protected α,γ-dioxygenated N-allylamides with wide scope, mostly good yields, and partly good diastereo- and enantioselectivity for defined combinations of chiral epoxides and chiral amides. This represents a very rare example of an oxidative geminal C–C/C–O difunctionalization next to carbonyl groups. The resulting dioxygenated allylic amides are subsequently subjected to persistent radical effect-based 5-exo-trig radical cyclization reactions providing functionalized pyrrolidones in high yields as diastereomeric mixtures. They converge to 3,4-trans-γ-lactams by base-mediated equilibration, which can be easily further diversified. Stereochemical models for both reaction types were developed.

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“…The pyrrole ring represents not only an essential motif of natural products and biologically important molecules but also one kind of significant precursors for the synthesis of pharmaceutical molecules and functional materials . Meanwhile, the introduction of a trifluoromethyl group into pharmaceutical molecules would significantly improve their bioreceptor selectivities .…”

Section: Introductionmentioning

confidence: 99%

Photoredox-Enabled Synthesis of β-Substituted Pyrroles from Pyrrolidines

Yang

Qiu

et al. 2020

J. Org. Chem.

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The merger of photoredox-initiated enamine–imine tautomerization and nucleophilic addition processes to access β-substituted pyrroles from pyrrolidines has been achieved. The significant advantage of this method is suppressing the Friedel–Crafts reaction, which usually occurs between N-aryl pyrrolidines and the highly electrophilic ketoesters. The good functional group tolerance, high atom economy, and high regioselectivity as well as easy handling conditions make it an appealing alternative to synthesize β-substituted pyrroles.

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Pyrrole and Its Derivatives

Cited by 34 publications

References 98 publications

Evolution of a Synthetic Strategy for Complex Polypyrrole Alkaloids: Total Syntheses of Curvulamine and Curindolizine

Evolution of a Synthetic Strategy for Complex Polypyrrole Alkaloids: Total Syntheses of Curvulamine and Curindolizine

α,γ-Dioxygenated amides via tandem Brook rearrangement/radical oxygenation reactions and their application to syntheses of γ-lactams

Photoredox-Enabled Synthesis of β-Substituted Pyrroles from Pyrrolidines

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