Recent Asymmetric Syntheses of Tetrahydroisoquinolines Using “Named” and Some Other Newer Methods

Zein, Ahmed L.; Valluru, Gopikishore; Georghiou, Paris E.

doi:10.1016/b978-0-444-59530-0.00003-4

Cited by 9 publications

(6 citation statements)

References 67 publications

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“…Yields for product formation from N -alkyl iminiums ( 54 , 55 ) are higher than those arising from N -aryl iminiums ( 56 , 57 ). 2,2-Disubstituted pyrrolidines analogous to 54 are useful building blocks for the synthesis of organocatalysts, while isoquinoline and morpholine structures related to 55 and 57 , respectively, are prevalent in natural products and bioactive pharmacophores. ,, Product 56 demonstrates not only that N -aryl imines can be utilized but also that aldimine (as opposed to ketimine) derivatives are suitable substrates.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Synthesis of Hindered Primary and Secondary Amines via Proton-Coupled Electron Transfer

et al. 2019

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Accessing hindered amines, particularly primary amines α to a fully substituted carbon center, is synthetically challenging. We report an electrochemical method to access such hindered amines starting from benchtop-stable iminium salts and cyanoheteroarenes. A wide variety of substituted heterocycles (pyridine, pyrimidine, pyrazine, purine, azaindole) can be utilized in the cross-coupling reaction, including those substituted with a halide, trifluoromethyl, ester, amide, or ether group, a heterocycle, or an unprotected alcohol or alkyne. Mechanistic insight based on DFT data, as well as cyclic voltammetry and NMR spectroscopy, suggests that a proton-coupled electron-transfer mechanism is operational as part of a hetero-biradical cross-coupling of α-amino radicals and radicals derived from cyanoheteroarenes.

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Section: Resultsmentioning

confidence: 99%

Electrochemical Synthesis of Hindered Primary and Secondary Amines via Proton-Coupled Electron Transfer

et al. 2019

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“…Several review articles on the asymmetric synthesis of isoquinoline alkaloids concerning, e.g., one class of alkaloids − or the methods of their synthesis, − as well as still important older classic works − should be mentioned.…”

Section: Introductionmentioning

confidence: 98%

Asymmetric Synthesis of Isoquinoline Alkaloids: 2004–2015

2016

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In the past decade, the asymmetric synthesis of chiral nonracemic isoquinoline alkaloids, a family of natural products showing a wide range of structural diversity and biological and pharmaceutical activity, has been based either on continuation or improvement of known traditional methods or on new, recently developed, strategies. Both diastereoselective and enantioselective catalytic methods have been applied. This review describes the stereochemically modified traditional syntheses (the Pictet-Spengler, the Bischler-Napieralski, and the Pomeranz-Fritsch-Bobbitt) along with strategies based on closing of the nitrogen-containing ring B of the isoquinoline core by the formation of bonds between C-N, N-C, C-N/N-C, and C-N/C-C atoms. Methods involving introduction of substituents at the C1 carbon of isoquinoline core along with syntheses applying various biocatalytic techniques have also been reviewed.

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“…However, despite significant progress, general de novo syntheses of isoquinolinone and tetrahydroisoquinoline (THIQ) motifs remain limited, with many modern techniques relying on well-established classical methodologies mimicking known biosyntheses of these structures. , The most prominent examples are more than a century old and include the Pictet–Spengler cyclization, , Bischler–Napieralski dihydroisoquinoline cyclization, Pomeranz–Fritsch–Bobbitt isoquinoline synthesis, Dieckmann cyclization [(a), Scheme ], and approaches based on Friedel–Crafts alkylation . These venerable reactions proceed via an electrophilic aromatic substitution (S E Ar) mechanism and thus are well-suited to the archetypal electron-rich catechol and mescalin motifs found in myriad natural products and pharmaceuticals.…”

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confidence: 99%

Lithioarene Cycliacylation and Pd-Catalyzed Aminoethylation/Cyclization to Access Electronically Diverse Saturated Isoquinoline Derivatives

et al. 2021

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We report operationally facile methods for the synthesis of substituted dihydroisoquinolinones and tetrahydroisoquinolines from readily accessible o-bromobenzyl bromides and o-bromobenzaldehydes, respectively. While classical electrophilic aromatic substitution reactions are tailored to the construction of saturated isoquinolines derived from electron-rich precursors, we demonstrate efficient syntheses from electronically diverse substrates to produce cyclized products as single regioisomers.

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Recent Asymmetric Syntheses of Tetrahydroisoquinolines Using “Named” and Some Other Newer Methods

Cited by 9 publications

References 67 publications

Electrochemical Synthesis of Hindered Primary and Secondary Amines via Proton-Coupled Electron Transfer

Electrochemical Synthesis of Hindered Primary and Secondary Amines via Proton-Coupled Electron Transfer

Asymmetric Synthesis of Isoquinoline Alkaloids: 2004–2015

Lithioarene Cycliacylation and Pd-Catalyzed Aminoethylation/Cyclization to Access Electronically Diverse Saturated Isoquinoline Derivatives

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