Regioselective Intramolecular Dipolar Cycloaddition of Azides and Unsymmetrical Alkynes

Brawn, Ryan A.; Welzel, Morgan; Lowe, Jason T.; Panek, James S.

doi:10.1021/ol902681t

Cited by 56 publications

(15 citation statements)

References 25 publications

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“…Allenylsilane 22 can also undergo a S N 2' substitution with an allylic acetate derivative to give a syn-allylic compound 25 (Scheme 6). [35] Likewise, the electro-philic fluorodesilylation of enantioenriched allenylsilanes was reported by Gouverneur and co-workers. It was found that the reaction proceeds with efficient transfer of chirality.…”

Section: Allenylsilane Reagentsmentioning

confidence: 77%

Allenes in Catalytic Asymmetric Synthesis and Natural Product Syntheses

2012

Angew Chem Int Ed

1,004

259

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Allenes are the simplest class of cumulenes, with two contiguous C=C bonds, and show unique physical and chemical properties. These features make allenes particularly attractive in modern organic chemistry. In this Review, attention is paid to the advances made in catalytic asymmetric synthesis and natural product syntheses based on well-established reactions of allenes, such as propargylation, addition, cycloaddition, cycloisomerization, cyclization, etc., with or without catalysts. Their versatile reactivity, substituent-loading ability, axial to center chirality transfer, and controllable selectivity allow access to target molecules by unique and efficient approaches. The main topics in this Review are presented with selected examples from 2003 to 2011.

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Section: Allenylsilane Reagentsmentioning

confidence: 77%

Allenes in Catalytic Asymmetric Synthesis and Natural Product Syntheses

2012

Angew Chem Int Ed

1,004

259

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“…A number of approaches are available for the synthesis of 1,2,3‐triazoles3,5 as well as benzothiadiazepine 1,1‐oxide derivatives 2. In addition, the synthesis of several fused triazoles has been reported in the literature 6a–i. However, to the best of our knowledge, the synthesis of a 1,2,3‐triazole fused with benzothiadiazepine 1,1‐oxides by using this strategy, has not yet been reported 6j.…”

Section: Methodsmentioning

confidence: 99%

One‐Pot Synthesis of Triazolothiadiazepine 1,1‐Dioxide Derivatives via Copper‐Catalyzed Tandem [3+2] Cycloaddition/N‐Arylation

Barange

Kavala

et al. 2011

Adv Synth Catal

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“…The stabilization is provided by cis coplanar orientation of C−Si bond to the p‐orbital of carbocation . Brawn et al . designed a regioselective synthesis of densely functionalized chiral triazolo‐oxazepanes and dihydro‐pyridines utilizing enantioriched allenyl silane ( R ‐) 162 in good yields (Scheme ).…”

Section: Synthesis Of Chiral Fused 123‐triazolesmentioning

confidence: 99%

Chiral Fused 1,2,3‐Triazoles: A Synthetic Overview

2020

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Triazoles have always occupied a pivotal position in the field of medicinal and pharmaceutical chemistry. Recently, the area of chiral fused triazoles has gained attention. The synthetic routes to access chiral fused triazole may involve either a natural or synthetic chiral starting material with a suitably functionalized azide and alkyne component or isomer resolution to achieve chirality. Asymmetric synthesis methods using chiral complexes and organocatalysis have also emerged for obtaining chiral fused triazoles. Herein, we have described an up-to-date overview of different synthetic protocols applied to construct chiral fused 1,2,3-triazoles. Scheme 1. Basic methodologies for triazole construction. 2 3 4 5 6 7 8 . Yanai's stereo-divergent synthesis of ido-triazole ent-6 a and gluco-triazoles 7 a. Scheme 3. Yanai's diastereo-divergent synthesis of manno-, gulo-, galacto-and altro-triazoles. . Konda's synthesis of tricyclic triazolo-oxazepines 62. Scheme 15. Cobb's synthesis of spirocyclic triazolooxazine nucleosides 67. Scheme 16. Sen's synthesis of tetracyclic triazolo-oxazepines 69. to azide group and protected amine was propargylated to access azido-alkynes 122 c-h for triazole formation 124 (Scheme 29). The copper catalyzed version of this step was also carried out that gave almost approximately same yields in lesser Scheme 25. Chrandrasekaran's synthesis of triazolo-pyrazines and pyrazinones from amino acid derived sulfamidates. Scheme 26. Chrandrasekaran's synthesis of triazolo-pyrazinone 110 having pendant amino acid.structural features of triazoles, the authors carried out one pot hydrogenation and insitu Boc-protection of 155 a, followed by azidation and propargylation to afford azido-alkyne 160. Subsequently, thermal azide-alkyne cycloaddition furnished the triazole product 161 in good yield (Scheme 34).Allenyl silanes are extensively used in synthetic organic transformations and provide ready access to enantiopure pyrroles, oxiranes, furans and vinyl silanes. In lewis acid assisted reaction, allenyl silanes work as propargyl anion equivalents. Allenyl silane forms regioselective homopropargylic alcohol when treated with aldehyde and ketone. The stabilization is Scheme 31. Thomas's synthesis of steroidal fused 1,2,3-triazoles.Scheme 32. Thomas's synthesis of steroidal fused NH-1,2,3-triazoles and steroidal 4,5-fused triazolo-alkynes.

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Regioselective Intramolecular Dipolar Cycloaddition of Azides and Unsymmetrical Alkynes

Cited by 56 publications

References 25 publications

Allenes in Catalytic Asymmetric Synthesis and Natural Product Syntheses

Allenes in Catalytic Asymmetric Synthesis and Natural Product Syntheses

One‐Pot Synthesis of Triazolothiadiazepine 1,1‐Dioxide Derivatives via Copper‐Catalyzed Tandem [3+2] Cycloaddition/N‐Arylation

Chiral Fused 1,2,3‐Triazoles: A Synthetic Overview

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