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The use of readily available chiral trans-cyclohexanediamine-benzimidazole derivatives as bifunctional organocatalysts in the asymmetric electrophilic amination of unprotected 3-substituted oxindoles is presented. Different organocatalysts were evaluated; the most successful one contained a dimethylamino moiety (5). With this catalyst under optimized conditions, different oxindoles containing a wide variety of substituents at the 3-position were aminated in good yields and with good to excellent enantioselectivities using di-tert-butylazodicarboxylate as the aminating agent. The procedure proved to be also efficient for the amination of 3-substituted benzofuranones, although with moderate results. A bifunctional role of the catalyst, acting as Brønsted base and hydrogen bond donor, is proposed according to the experimental results observed.

The use of readily available chiral trans-cyclohexanediamine-benzimidazole derivatives as bifunctional organocatalysts in the asymmetric electrophilic amination of unprotected 3-substituted oxindoles is presented. Different organocatalysts were evaluated; the most successful one contained a dimethylamino moiety (5). With this catalyst under optimized conditions, different oxindoles containing a wide variety of substituents at the 3-position were aminated in good yields and with good to excellent enantioselectivities using di-tert-butylazodicarboxylate as the aminating agent. The procedure proved to be also efficient for the amination of 3-substituted benzofuranones, although with moderate results. A bifunctional role of the catalyst, acting as Brønsted base and hydrogen bond donor, is proposed according to the experimental results observed.

CrocaginA (1) combines an attractive molecular structure with an unusual biosynthesis and bioactivity. An efficient synthesis of crocaginA is presented that hinges on an early formation of the heterotricyclic core, an electrophilic amination, and the stereoselective hydrogenation of a tetrasubstituted double bond. This synthesis confirms the absolute configuration of crocaginA and provides access to the natural product and derivatives thereof for further biological testing.

CrocaginA (1) combines an attractive molecular structure with an unusual biosynthesis and bioactivity. An efficient synthesis of crocaginA is presented that hinges on an early formation of the heterotricyclic core, an electrophilic amination, and the stereoselective hydrogenation of a tetrasubstituted double bond. This synthesis confirms the absolute configuration of crocaginA and provides access to the natural product and derivatives thereof for further biological testing.

CrocaginA (1) combines an attractive molecular structure with an unusual biosynthesis and bioactivity. An efficient synthesis of crocaginA is presented that hinges on an early formation of the heterotricyclic core, an electrophilic amination, and the stereoselective hydrogenation of a tetrasubstituted double bond. This synthesis confirms the absolute configuration of crocaginA and provides access to the natural product and derivatives thereof for further biological testing.

The use of a trans-cyclohexanediamine benzimidazole derivative as a hydrogen-bond catalyst for the electrophilic amination of cyclic 1,3-dicarbonyl compounds is herein presented. High yields and enantioselectivities varying from moderate to excellent are generally obtained using mild reaction conditions and as low as 1 mol% of catalyst loading.

The use of a trans-cyclohexanediamine benzimidazole derivative as a hydrogen-bond catalyst for the electrophilic amination of cyclic 1,3-dicarbonyl compounds is herein presented. High yields and enantioselectivities varying from moderate to excellent are generally obtained using mild reaction conditions and as low as 1 mol% of catalyst loading.

The electrochemical process of anisole amination is studied in 1.5-9 M H2SO4 solutions containing acetonitrile or acetic acid. It is shown that the synthesis of aromatic monoamino compounds is better performed in moderately acidic media with high concentrations of organic solvents. Due to the chain mechanism of the electrochemical process, the current efficiency of amines can exceed 150% under these conditions. © 2009 Pleiades Publishing, Ltd.

Electrochemical amination of benzene in sulfuric acid electrolytes is studied and experimental conditions for highly efficient synthesis of primary aromatic amino compounds are determined. In the electrolysis of Ti(IV)-NH 2OH-C 6H 6 in 11 M H 2SO 4 solutions containing acetic acid or acetonitrile as organic solvents, aniline and isomeric phenylenediamines are obtained with the total yields by hydroxylamine of 95.6 and 99.6%, respectively. A monoamino compound is the main product of radical substitution in acidic organo-aqueous media. It is found that the use of acetonitrile in electrochemical process is limited to certain sulfuric acid concentrations and temperatures.

Electrolysis of the system Ti(IV)-NH 2OH-C 6H 6 in an 11 M H 2SO 4 solution shows that using an organic solvent (acetic acid, acetonitrile) during cathodically initiated amination of aromatic substrates permits the production of aromatic amines with the overall yield by hydroxylamine reaching 91%. Due to a chain mechanism of radical substitution, the benzene amination in electrolytes containing 5 M CH 3COOH and 5.5 M CH 3CN terminates largely upon consuming 70-75 and 50-55% of the charge required theoretically for a one-electron process. The maximum efficiency of electrochemical amination is observed at low hydroxylamine conversions and the overall current efficiency for mono- and disubstituted products of the benzene amination may exceed in these conditions 750%.

The electrochemical process of anisole amination is studied in 1.5-9 M H2SO4 solutions containing acetonitrile or acetic acid. It is shown that the synthesis of aromatic monoamino compounds is better performed in moderately acidic media with high concentrations of organic solvents. Due to the chain mechanism of the electrochemical process, the current efficiency of amines can exceed 150% under these conditions. © 2009 Pleiades Publishing, Ltd.

Electrolysis of the system Ti(IV)-NH 2OH-C 6H 6 in an 11 M H 2SO 4 solution shows that using an organic solvent (acetic acid, acetonitrile) during cathodically initiated amination of aromatic substrates permits the production of aromatic amines with the overall yield by hydroxylamine reaching 91%. Due to a chain mechanism of radical substitution, the benzene amination in electrolytes containing 5 M CH 3COOH and 5.5 M CH 3CN terminates largely upon consuming 70-75 and 50-55% of the charge required theoretically for a one-electron process. The maximum efficiency of electrochemical amination is observed at low hydroxylamine conversions and the overall current efficiency for mono- and disubstituted products of the benzene amination may exceed in these conditions 750%.

Electrochemical amination of benzene in sulfuric acid electrolytes is studied and experimental conditions for highly efficient synthesis of primary aromatic amino compounds are determined. In the electrolysis of Ti(IV)-NH 2OH-C 6H 6 in 11 M H 2SO 4 solutions containing acetic acid or acetonitrile as organic solvents, aniline and isomeric phenylenediamines are obtained with the total yields by hydroxylamine of 95.6 and 99.6%, respectively. A monoamino compound is the main product of radical substitution in acidic organo-aqueous media. It is found that the use of acetonitrile in electrochemical process is limited to certain sulfuric acid concentrations and temperatures.