Lithium Chloride Catalyzed Asymmetric Domino Aza‐Michael Addition/[3 + 2] Cycloaddition Reactions for the Synthesis of Spiro‐ and Bicyclic α,β,γ‐Triamino Acid Derivatives

Just, David; Hernández-Guerra, Daniel; Kritsch, Susanne; Pohl, Radek; Cı́sařová, Ivana; Jones, Peter G.; Mackman, Richard L.; Bahador, Gina; Jahn, Ullrich

doi:10.1002/ejoc.201800585

Cited by 6 publications

(6 citation statements)

References 62 publications

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“… − A direct and efficient synthesis of these functionally dense heterocycles from simple starting materials would be empowering. , Classically, tetrahydro-pyrrolo-pyrazole heterocycles are generated through cycloaddition of a diazo species with activated maleimide derivatives. , More recently, Zard demonstrated that hydrazones with pendant alkenes can be oxidized to the corresponding diazo species, which subsequently undergoes an intramolecular cycloaddition (Scheme a) . Jahn demonstrated that a domino aza -Michael reaction can afford similar heterocycles using n -BuLi and NfN 3 . , …”

Section: Introductionmentioning

confidence: 99%

A Cascade Reaction of Cinnamyl Azides with Acrylates Directly Generates Tetrahydro-Pyrrolo-Pyrazole Heterocycles

2020

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Developing reactions to generate complex and modular building blocks in a concise and direct fashion remains a contemporary synthetic challenge. This work describes a stereoselective cascade reaction between allylic azides and acrylates that directly generates tetrahydro-pyrrolo-pyrazole ring systems. These products contain up to four contiguous stereocenters, two of which may be tetrasubstituted carbon atoms attached to a nitrogen atom.Over 30 examples are provided with an average isolated yield of 71% (ranging from 40% to 94%). The reaction was easily scaled to use more than one gram of starting material, and the products can be readily diversified.

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Section: Introductionmentioning

confidence: 99%

A Cascade Reaction of Cinnamyl Azides with Acrylates Directly Generates Tetrahydro-Pyrrolo-Pyrazole Heterocycles

2020

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“…Regarding the optimized reaction conditions (Schemes 28 and 29), it was observed that the diastereomers' yields depend on the nature of cycloalkenylmethyl amines having five-or six-membered rings and α,β-unsaturated esters bearing alkyl or aryl substituents in β-position. In Scheme 30, the proposed mechanism for forming the tetrahedral-pyrrolo-pyrazole from the reaction of cycloalkenyl amines and α,β-unsaturated esters via intermediates 61-65 was postulated [25]. Moreover, Just and others [25] reported the catalytic syntheses of fused tricyclic pyrrolidinopyrazolines via aza-Michael cycloaddition of cyclic amines 55 as well as (R)-N-benzylcycloalkenyl amines 58 with NfN 3 45; the reaction was catalyzed by lithium chloride (LiCl).…”

Section: Synthesis Of the Pyrazole Ringmentioning

confidence: 99%

“…In Scheme 30, the proposed mechanism for forming the tetrahedral-pyrrolo-pyrazole from the reaction of cycloalkenyl amines and α,β-unsaturated esters via intermediates 61-65 was postulated [25]. Moreover, Just and others [25] reported the catalytic syntheses of fused tricyclic pyrrolidinopyrazolines via aza-Michael cycloaddition of cyclic amines 55 as well as (R)-N-benzylcycloalkenyl amines 58 with NfN 3 45; the reaction was catalyzed by lithium chloride (LiCl). Diastereoselective products have been obtained in good yields (68-84%) for the tricyclic products (trans)-56a-f and (cis)-57a-f, while in the case of 5,5,5-tricyclic (trans)-59a-d and (cis)-60a-d, the yield ranged from 72 to 85%.…”

Section: Synthesis Of the Pyrazole Ringmentioning

confidence: 99%

Section: Synthesis Of the Pyrazole Ringmentioning

confidence: 99%

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Azides in the Synthesis of Various Heterocycles

et al. 2022

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In this review, we focus on some interesting and recent examples of various applications of organic azides such as their intermolecular or intramolecular, under thermal, catalyzed, or noncatalyzed reaction conditions. The aforementioned reactions in the aim to prepare basic five-, six-, organometallic heterocyclic-membered systems and/or their fused analogs. This review article also provides a report on the developed methods describing the synthesis of various heterocycles from organic azides, especially those reported in recent papers (till 2020). At the outset, this review groups the synthetic methods of organic azides into different categories. Secondly, the review deals with the functionality of the azido group in chemical reactions. This is followed by a major section on the following: (1) the synthetic tools of various heterocycles from the corresponding organic azides by one-pot domino reaction; (2) the utility of the chosen catalysts in the chemoselectivity favoring C−H and C-N bonds; (3) one-pot procedures (i.e., Ugi four-component reaction); (4) nucleophilic addition, such as Aza-Michael addition; (5) cycloaddition reactions, such as [3+2] cycloaddition; (6) mixed addition/cyclization/oxygen; and (7) insertion reaction of C-H amination. The review also includes the synthetic procedures of fused heterocycles, such as quinazoline derivatives and organometal heterocycles (i.e., phosphorus-, boron- and aluminum-containing heterocycles). Due to many references that have dealt with the reactions of azides in heterocyclic synthesis (currently more than 32,000), we selected according to generality and timeliness. This is considered a recent review that focuses on selected interesting examples of various heterocycles from the mechanistic aspects of organic azides.

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Synthesis and biological activity of potential antiviral compounds through 1,3-dipolar cycloadditions. Part 2: nitrones, nitrile oxides and imines, and other 1,3-dipoles

Quadrelli¹,

Mella²,

Faita³

2023

Arkivoc

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Prominent in the current stage of drug development, antiviral compounds can be efficiently prepared through cycloaddition reactions. This review reports the use of 1,3-dipolar cycloadditions of nitrones, nitrile oxides and imines and other 1,3-dipoles in the light of their application for the preparation of synthons in the design and synthesis of compounds that were tested for their antiviral activities against a variety of viruses. Since nitrile oxides represent valuable precursors of nitrosocarbonyl intermediates, their use in the synthesis of antiviral compounds is reported. The products obtained from these pericyclic reaction approaches were tested for their activities in terms of blocking the virus replication and the relevant biological data are highlighted.

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Lithium Chloride Catalyzed Asymmetric Domino Aza‐Michael Addition/[3 + 2] Cycloaddition Reactions for the Synthesis of Spiro‐ and Bicyclic α,β,γ‐Triamino Acid Derivatives

Cited by 6 publications

References 62 publications

A Cascade Reaction of Cinnamyl Azides with Acrylates Directly Generates Tetrahydro-Pyrrolo-Pyrazole Heterocycles

A Cascade Reaction of Cinnamyl Azides with Acrylates Directly Generates Tetrahydro-Pyrrolo-Pyrazole Heterocycles

Azides in the Synthesis of Various Heterocycles

Synthesis and biological activity of potential antiviral compounds through 1,3-dipolar cycloadditions. Part 2: nitrones, nitrile oxides and imines, and other 1,3-dipoles

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