A Metal and Base-Free Chemoselective Primary Amination of Boronic Acids Using Cyanamidyl/Arylcyanamidyl Radical as Aminating Species: Synthesis and Mechanistic Studies by Density Functional Theory.

doi:10.1021/acs.joc.6b00671

Paper

A Metal and Base-Free Chemoselective Primary Amination of Boronic Acids Using Cyanamidyl/Arylcyanamidyl Radical as Aminating Species: Synthesis and Mechanistic Studies by Density Functional Theory.

Published 2016 · Nachiketa Chatterjee, Minhajul Arfeen, Prasad V Bharatam

The Journal of organic chemistry

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15

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Abstract

An efficient, metal and base-free, chemoselective synthesis of aryl-, heteroaryl-, and alkyl primary amines from the corresponding boronic acids has been achieved at ambient temperature mediated by [bis(trifluoroacetoxy)iodo]benzene (PIFA) and N-bromosuccinimide (NBS) using cyanamidyl/arylcyanamidyl radicals as the aminating species. The primary amine compounds were initially obtained as their corresponding ammonium trifluoroacetate salts which, on treatment with aq NaOH, provide the free amines. Finally, the primary amines were isolated through column chromatography over silica-gel using hexane-EtOAc solvent system as the eluent. The reactions are sufficiently fast, completing within 1 h. Quantum chemical calculations in combination with experimental observations validate that the ipso amination of substituted boronic acids involves the formation of cyanamidyl/arylcyanamidyl radical, followed by regiospecific interaction of its nitrile-N center with boron atom of the boronic acids, leading to chemoselective primary amination.

Study Snapshot

This study demonstrates a metal and base-free chemoselective primary amination of boronic acids using cyanamidyl/arylcyanamidyl radicals, leading to efficient synthesis of aryl-, heteroaryl-, and alkyl primary amines within 1

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

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Paper

A Metal and Base-Free Chemoselective Primary Amination of Boronic Acids Using Cyanamidyl/Arylcyanamidyl Radical as Aminating Species: Synthesis and Mechanistic Studies by Density Functional Theory.

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References

Mechanism of the Paal–Knorr reaction: the importance of water mediated hemialcohol pathway

The Paal-Knorr reaction is an efficient method for generating important heterocycles, with a water-mediated hemialcohol pathway being the preferred energy-efficient pathway for pyrrole and thiophene synthesis.

Sequential Oxidative α-Cyanation/Anti-Markovnikov Hydroalkoxylation of Allylamines.

This method efficiently generates 2-amino-4-alkoxybutanenitriles from three reactants (allylamines, trimethylsilyl cyanide, and alcohols) at ambient temperature, with minimal waste.

Metal and base free synthesis of primary amines via ipso amination of organoboronic acids mediated by [bis(trifluoroacetoxy)iodo]benzene (PIFA).

This metal and base-free synthesis of primary amines using organoboronic acids and PIFA-NBS is a milder alternative to strong bases, allowing for rapid reaction and aqueous alkaline work-up.

Organotrifluoroborates: Another Branch of the Mighty Oak.

Organotrifluoroborates are versatile reagents for organic synthesis due to their ease of preparation, stability, and unique reactivity patterns, offering access to substructural entities not readily accessible with other organometallic reagents.

A novel transition metal free [bis-(trifluoroacetoxy)iodo]benzene (PIFA) mediated oxidative ipso nitration of organoboronic acids.

This novel method for oxidative ipso nitration of organoboronic acids at ambient temperature provides a mild, convenient, and transition metal-free method for producing nitroarenes.

Organic hypervalent iodine(III) catalyzed ipso-hydroxylation of aryl- and alkylboronic acids/esters

Organic hypervalent iodine(III) catalyzed hydroxylation of organoboronic compounds is a highly efficient method for modifying functionalized aryl- and alkylboronic acids/esters.

Oxidative dimerization of 2-oxindoles promoted by KO(t)Bu-I₂: total synthesis of (±)-folicanthine.

This study demonstrates a 'transition-metal-free' oxidative coupling of 2-oxindoles, yielding diverse structurally different homo- and heterodimerized 2-oxindoles with vicinal all-carbon quaternary centers, potentially leading to a radical-driven pathway.

Transition-metal-free access to primary anilines from boronic acids and a common (+)NH2 equivalent.

This study demonstrates a transition-metal-free method for preparing primary anilines from boronic acids and a common (+)NH2 equivalent, enabling the synthesis of aromatic amines with unique substitution patterns.

The stability of nitrogen-centered radicals.

The stability of nitrogen-centered radicals varies, with the -type radical being the most stable, influenced by resonance delocalization, electron donation, and ring strain effects.

Citations

N-Hydroxyphthalimides as Nitrogen Radical Precursors in the Copper-Catalyzed Radical Cross-Coupling Amination of Arylboronic Acids: Synthesis of Arylamines.

Copper-catalyzed radical cross-coupling amination of arylboronic acids allows for the efficient synthesis of arylamines with up to 98% yield and across a wide range of functional group tolerances.

Rapid and General Amination of Aryl Boronic Acids and Esters Using O-(Diphenylphosphinyl)hydroxylamine (DPPH).

DPPH rapidly converts (hetero)aryl boronic acids and esters to primary anilines, offering broad substrate scope and functional-group tolerance, making it useful for accessing electron-deficient (hetero)aryl anilines.

Cyclic diaryliodonium salts: applications and overview.

Cyclic diaryliodonium salts are efficient starting materials for bioactive compounds, making them essential for pharmaceutical synthesis due to their high optical activity and enantiomeric excess.

Substituent Effects and the Energetics of Noncatalyzed Aryl Halide Aminations: A Theoretical Investigation

Substituent effects significantly influence the activation energies for noncatalyzed amination of aryl halides, with the 2-COOHPhI + NH2nPr reaction possessing the lowest activation free energy.

Saturated boronic acids, boronates, and trifluoroborates: an update on their synthetic and medicinal chemistry.

Recent advances in saturated boronic acids, boronates, and trifluoroborates have led to new synthetic methods and applications in boron-containing drug design.