ChemInform Abstract: Stereoselective Synthesis of Amido and Phenyl Azabicyclic Derivatives via a Tandem Aza Prins‐Ritter/Friedel—Crafts Type Reaction of Endocyclic N‐Acyliminium Ions.

Indukuri, Kiran; Unnava, Ramanjaneyulu; Deka, Manash Jyoti; Saikia, Anil K.

doi:10.1002/chin.201415174

Cited by 4 publications

(6 citation statements)

References 1 publication

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“…Both amidoand phenyl-substituted azabicyclic compounds could be generated in a highly diastereoselective manner with good to excellent yields. 69 In most cases (18a−18h and 19a−19d), a single diastereomer was exclusively formed. The diastereomeric ratio was determined by 1 H NMR spectroscopy, and the diastereomeric identity was confirmed by NOESY and X-ray crystallographic analysis.…”

Section: Reactivity and Stereochemistrymentioning

confidence: 99%

“…However, the excellent diastereoselectivity was lost when a tertiary carbocation derived from substrate 16a was used for the aza-Prins−Ritter hydrolysis sequence (Scheme 7). 69 The same group reported the synthesis of tosylated bi-and tricyclic scaffolds through aza-Prins cyclization. In these reactions, the p-toluenesulfonic acid functioned as both a Brønsted acid catalyst and a reactive nucleophile.…”

Section: Reactivity and Stereochemistrymentioning

confidence: 99%

“…70 Bicyclic isoindolin-1-one compounds 23 underwent similar aza-Prins−Ritter and aza-Prins/Friedel− Crafts sequences to give tricyclic amido-substituted compounds 25 and phenyl-substituted compounds 26, respectively (Scheme 9). 69 Starting from acyclic precursors, Dobbs and co-workers reported the synthesis of analogous bicyclic [6,5] and [6,6] aza scaffolds relying on aza-Prins and aza-silyl-Prins reactions with concomitant incorporation of halo, phenyl, and amido substituents. Substrates 27a and 27b, containing both amide and aldehyde functional groups, the latter masked with an acetal protecting group, underwent intramolecular NAI formation and subsequent aza-Prins (28) or aza-silyl-Prins cyclization (29).…”

Section: Reactivity and Stereochemistrymentioning

confidence: 99%

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Scaffold Diversity from N-Acyliminium Ions

Nielsen

2017

Chem. Rev.

167

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N-Acyliminium ions are powerful reactive species for the formation of carbon-carbon and carbon-heteroatom bonds. Strategies relying on intramolecular reactions of N-acyliminium intermediates, also referred to as N-acyliminium ion cyclization reactions, have been employed for the construction of structurally diverse scaffolds, ranging from simple bicyclic skeletons to complex polycyclic systems and natural-product-like compounds. This review aims to provide an overview of cyclization reactions of N-acyliminium ions derived from various precursors for the assembly of structurally diverse scaffolds, covering the literature over the past 12 years (from 2004 to 2015).

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Section: Reactivity and Stereochemistrymentioning

confidence: 99%

Section: Reactivity and Stereochemistrymentioning

confidence: 99%

Section: Reactivity and Stereochemistrymentioning

confidence: 99%

See 1 more Smart Citation

Scaffold Diversity from N-Acyliminium Ions

Nielsen

2017

Chem. Rev.

167

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“…In the absence of a suitable nucleophile, it is also known that solvents such as acetonitrile or benzene can trap the cyclic secondary carbocation, in an aza-Prins-Ritter or aza-Prins-Friedel−Crafts cascade. 21,36 Using pTSA in acetonitrile gave good yields of the 4-NHAc trapped products (Table 3), again as a single enantiomer and diastereomer.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

A Stereoselective aza-Prins Reaction: Rapid Access to Enantiopure Piperidines and Pipecolic Acids

et al. 2021

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The aza-Prins reaction is a widely employed and highly efficient method for the preparation of saturated nitrogencontaining heterocycles. Its major drawback has always been a lack of diastereoselectivity and the formation of racemic products. Herein we address these problems and report, for the first time, the synthesis of both diastereomerically and enantiopure multiplysubstituted piperidines via the aza-Prins reaction. This method will be widely applicable for natural product synthesis and is exemplified here by the synthesis of enantiopure pipecolic acid derivatives.

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“…27 Furthermore, tandem reactions were developed by applying the Ritter reaction to carbocations that were generated in situ by the preparation of azabicyclic alkaloids via a Prins-type reactions. 28 The generation of the carbocation in the Ritter reaction can also be obtained via the decomposition of diazonium salts. 29 Although this procedure has been applied often for the synthesis of arylamides, there are only few reports of triazenes, which can be seen as protected and more stable diazonium salts, being converted to amides.…”

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confidence: 99%

Synthesis of Arylamides via Ritter-Type Cleavage of Solid-Supported Aryltriazenes

2019

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A novel route for the synthesis of N-arylamides via the cleavage of aryltriazenes with alkyl or aryl nitriles is presented. We developed a variation of the Ritter reaction that allows the use of acetonitrile as solvent and reagent in reactions with solid-supported precursors. The reaction was optimized for the generation of N-aryl acetamides using a diverse range of immobilized building blocks including o-, m-, and p-substituted aryltriazenes. The cleavage via the Ritter-type conversion was combined with an on-bead cross-coupling reaction of halogen-substituted aryltriazenes with pyrazoles. Additionally, the synthesis of on-bead generated arylboronic estersubstituted triazenes was shown. The developed procedure was further expanded to use other commercially available nitriles, such as acrylonitrile, benzonitrile, and chlorinated alkyl nitriles as suitable reagents for a Ritter-type cleavage of the prepared triazene linkers.

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ChemInform Abstract: Stereoselective Synthesis of Amido and Phenyl Azabicyclic Derivatives via a Tandem Aza Prins‐Ritter/Friedel—Crafts Type Reaction of Endocyclic N‐Acyliminium Ions.

Cited by 4 publications

References 1 publication

Scaffold Diversity from N-Acyliminium Ions

Scaffold Diversity from N-Acyliminium Ions

A Stereoselective aza-Prins Reaction: Rapid Access to Enantiopure Piperidines and Pipecolic Acids

Synthesis of Arylamides via Ritter-Type Cleavage of Solid-Supported Aryltriazenes

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