S-Benzyl isothiouronium chloride as a recoverable organocatalyst for the direct reductive amination of aldehydes

Synthesis and crystal structure of (E)-2-benzyl-1,3-di-phenyl-iso-thio-uronium iodide

In the title mol-ecular salt, C₂₀H₁₉N₂S⁺·I^-, prepared by the reaction of 1,3-di-phenyl-thio-urea and benzyl iodide, the C-S-C thio-ether bond angle is 101.66 (9)° and electrons are delocalized over the N⁺= C-N skeleton. The dihedral angle between the aromatic rings attached to the N atoms is 40.60 (9)°. In the crystal, N-H⋯I hydrogen bonds link the components into [100] chains.

Catalyst-free reductive amination of aromatic aldehydes with ammonium formate and Hantzsch ester

The protocol of the reductive amination of aromatic aldehydes using ammonium formate and Hantzsch ester is described. It is a mild, convenient, acid- and catalyst-free system applied for the synthesis of both symmetric and asymmetric aromatic secondary amines.

One-Pot Reductive Amination of Araldehydes by Aniline Using Borohydride with Cecl3·7H2O as Catalyst

A one-pot, two-step reductive amination of araldehydes or acetophenones with anilines using NaBH4 as a cheap hydride source and catalysed by CeCl3·7H2O has been achieved in EtOH at room temperature in good yields.

Recent advances in catalytic C-N bond formation: a comparison of cascade hydroaminomethylation and reductive amination reactions with the corresponding hydroamidomethylation and reductive amidation reactions

The design and catalytic implementation of tandem reactions to selectively create nitrogen-containing products under mild conditions has encountered numerous challenges in synthetic chemistry. Several known classes of homogeneously catalyzed carbon-nitrogen bond formation including hydroamination, hydroamidation, hydroaminoalkylation, hydroaminomethylation and reductive amination were reported in the literature. More recently, a new class of C-N bond formation consisting of hydroamidomethylation and reductive amidation extended the applicability of these synthetic methodologies. The tandem reactions do considerably impact on the selectivity and efficiency of synthetic strategies. This review highlights and compares selected examples of the hydroaminomethylation, reductive amination, hydroamidomethylation and reductive amidation reactions, and thus consequently reveals their potential applications in synthetic chemistry as well as chemical industries.

Ultrasound-assisted solventless synthesis of amines by in situ oxidation/reductive amination of benzyl halides

Ultrasound-assisted solventless oxidation/reductive amination of benzyl halides was developed as a facile, efficient, and environmentally friendly method toward N-alkylated amines.

Chemo- and regioselective homogeneous rhodium-catalyzed hydroamidomethylation of terminal alkenes to N-alkylamides

A rhodium/xantphos homogeneous catalyst system has been developed for direct chemo- and regioselective mono-N-alkylation of primary amides with 1-alkenes and syngas through catalytic hydroamidomethylation with 1-pentene and acetamide as model substrates. For appropriate catalyst performance, it appears to be essential that catalytic amounts of a strong acid promoter, such as p-toluenesulfonic acid (HOTs), as well as larger amounts of a weakly acidic protic promoter, particularly hexafluoroisopropyl alcohol (HOR(F) ) are applied. Apart from the product N-1-hexylacetamide, the isomeric unsaturated intermediates, hexanol and higher mass byproducts, as well as the corresponding isomeric branched products, can be formed. Under optimized conditions, almost full alkene conversion can be achieved with more than 80% selectivity to the product N-1-hexylamide. Interestingly, in the presence of a relatively high concentration of HOR(F) , the same catalyst system shows a remarkably high selectivity for the formation of hexanol from 1-pentene with syngas, thus presenting a unique example of a selective rhodium-catalyzed hydroformylation-hydrogenation tandem reaction under mild conditions. Time-dependent product formation during hydroamidomethylation batch experiments provides evidence for aldehyde and unsaturated intermediates; this clearly indicates the three-step hydroformylation/condensation/hydrogenation reaction sequence that takes place in hydroamidomethylation. One likely role of the weakly acidic protic promoter, HOR(F) , in combination with the strong acid HOTs, is to establish a dual-functionality rhodium catalyst system comprised of a neutral rhodium(I) hydroformylation catalyst species and a cationic rhodium(III) complex capable of selectively reducing the imide and/or ene-amide intermediates that are in a dynamic, acid-catalyzed condensation equilibrium with the aldehyde and amide in a syngas environment.