Direct Reductive Amination Of Aldehydes Research Articles

Green synthesis and catalytic properties of palladium nanoparticles for the direct reductive amination of aldehydes and hydrogenation of unsaturated ketones

This paper reports on the synthesis and use of palladium nanoparticles as heterogeneous catalysts for the reductive amination of aldehydes and hydrogenation of unsaturated ketones. This method has the advantages of high yields, simple methodology and easy work up. The catalyst can be recovered and reused several times without significant loss of catalytic activity.

Ruthenium-Catalyzed Direct Reductive Amination in HCOOH/NEt3 Mixture

A one-pot direct reductive amination of aldehydes with primary and secondary amines using Noyori’s catalyst (η 6-arene)Ru(H)TsDPEN in neat HCOOH/NEt3 mixture has been developed. The catalyst formed in situ allows full conversion of aldehydes with high selectivities towards the desired amine products within hours or even minutes at room temperature. For aromatic aldehydes, both 5:2 and 5:3 HCOOH/NEt3 mixtures prove to be suitable reaction media, with the former affording higher selectivities while the latter leading to much faster reaction rates. For aliphatic aldehydes, the 5:3 HCOOH/NEt3 mixture gives much higher selectivities due to the minimal loss from aldol condensation. This method has great application potential for the synthesis of amine products given the mild conditions.

Aqueous-phase catalytic oxidation, transfer hydrogenation, reductive amination and hydration reactions

As part of our work devoted to the synthesis of organic compounds using “green” processes, we developed several water-soluble catalysts that allow efficiently the synthesis of ketones, amines, alcohols and amides. CuCl2·2H2O combined to 2,2′-biquinoline-4,4′-dicarboxylic acid dipotassium salt (BQC) was reported as an active catalyst for the selective oxidation with TBHP of alcohols, alkylarenes and alkynes. We developed also successfully hydrogen transfer reactions. While [Ir(COD)Cl]2/BQC proved to be efficient for Oppenauer-type oxidation of secondary alcohols, [Rh(COD)Cl]2/P(m-C6H4SO3Na)3 (TPPTS) showed very good activities for Meerwein–Ponndorf–Verley-type reduction of ketones and aldehydes. Higher alkylated amines and amides were also synthesized respectively, by direct reductive amination of aldehydes with primary and secondary amines catalyzed by water soluble Pd(PhCN)2Cl2/BQC, and hydration of nitriles with [Rh(COD)Cl]2/TPPTS. Many of these catalytic systems are recycled with no significant loss of activity and the final products are isolated in easy manners.

Palladium supported on hollow magnetic mesoporous spheres as recoverable catalyst for one-pot reductive amination of aldehydes with nitroarenes under mild conditions

We described here a method to stabilize Pd(0) on the surface of hollow magnetic mesoporous spheres (HMMS), with Fe3O4 nanoparticles embedded in the mesoporous shell. The catalyst was characterized by TEM, XRD and VSM. It was found that the catalyst showed a high activity for the one-pot direct reductive amination of aldehydes with nitroarenes in the presence of molecular hydrogen in ethanol, even at room temperature. Besides, the catalyst could be recovered in a facile manner from the reaction mixture and recycled six times without loss in activity.

ChemInform Abstract: Solvent‐ and Catalyst‐Free Direct Reductive Amination of Aldehydes and Ketones with Hantzsch Ester: Synthesis of Secondary and Tertiary Amines.

AbstractThe parallel synthesis of a series of secondary and tertiary amines is achieved by the direct reductive amination of aldehydes and ketones with a biomimetic and safe reducing agent under solvent‐ and catalyst‐free as well as metal‐ and acid‐free conditions.

Direct Reductive Amination of Aldehydes Catalyzed by Carbon Nanotube/Gold Nanohybrids

Gold digger: The direct reductive amination of aldehydes catalyzed by gold/carbon-nanotube nanohybrids with a silane as a hydride source is reported. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Solvent- and catalyst-free direct reductive amination of aldehydes and ketones with Hantzsch ester: synthesis of secondary and tertiary amines

A facile and rapid method for the parallel synthesis of a series of secondary and tertiary amines by the direct reductive amination of aldehydes and ketones with Hantzsch ester under solvent- and catalyst-free has been developed. The scope and limitation of this method are described.

Palladium supported on magnetic nanoparticles as recoverable catalyst for one-pot reductive amination of aldehydes with nitroarenes under ambient conditions

Abstract A high-performance palladium-based catalyst has been prepared by the co-precipitation method. The catalyst was characterized by TEM, XRD, VSM and ICP. It was found that the catalyst showed a high activity for the one-pot direct reductive amination of aldehydes with nitroarenes in the presence of molecular hydrogen in ethanol, even at room temperature. Furthermore, the catalyst was easily recovered by applying an external magnet and reused for eight cycles without significant loss of activity.

ChemInform Abstract: Direct Reductive Amination of Aldehydes Using Lithium—Arene (cat.) as Reducing System: A Simple One‐Pot Procedure for the Synthesis of Secondary Amines.

AbstractMain products are the expected secondary amines or analogous imines for substrates having electron‐withdrawing groups.

Sulfonated multiwalled carbon nanotubes (MWCNTs) as a new, efficient, and recyclable heterogeneous nanocatalyst for the synthesis of amines

Sulfonated multiwalled carbon nanotubes (MWCNTs) were synthesized by chemical vapor deposition (CVD) as a new and facile one-pot method using acetylene (as the CNT precursor), thiophene (as the sulfur precursor), and ferrocene (for in situ liberation of metal nanoparticles as the CNT nanocatalyst). A low catalytic amount of the resulting sulfonated MWCNTs with a turnover number (TON) up to 980 and a turnover frequency (TOF) up to 11 160 h–1 was utilized as a new and recyclable heterogeneous nanocatalyst for the efficient one-pot synthesis of various amines (secondary and tertiary) by direct reductive amination of aldehydes and ketones using NaBH4. The catalyst was easily isolated from the reaction mixture by simple filtration and reused at least five times without significant degradation in activity.

A one-pot selective synthesis of N-Boc protected secondary amines: tandem direct reductive amination/N-Boc protection

A one-pot tandem direct reductive amination of aldehydes with primary amines resulting in N-Boc secondary amines using a (Boc)2O/sodium triacetoxyborohydride (STAB) system is reported. The tandem procedure is efficient, selective, and versatile, giving excellent yields of N-Boc protected secondary amines even in those cases where the products are prone to intramolecular lactamization.

Direct reductive amination of aldehydes using lithium-arene(cat.) as reducing system. A simple one-pot procedure for the synthesis of secondary amines

A simple one-pot procedure for the direct reductive amination of aldehydes using lithium powder and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB) or a polymer supported naphthalene as reducing system is described. The direct reductive amination of a variety of aldehydes with primary amines was achieved simply by adding a mixture of the corresponding carbonyl compound and the amine, over a solution of the lithium arenide in THF at room temperature. For most of the substrates tested the main reaction products were the secondary amines along with variable amounts of the corresponding alcohol and/or imine products. Theoretical DFT calculations have been applied in order to explain the differences in reactivity observed for aromatic substrates.

ChemInform Abstract: S‐Benzyl Isothiouronium Chloride as a Recoverable Organocatalyst for the Direct Reductive Amination of Aldehydes.

AbstractA broad spectrum of amines can be prepared from either aromatic or aliphatic aldehydes and various functionalities are tolerated.

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

The direct reductive amination of aldehydes using S-benzyl isothiouronium chloride as a recoverable organocatalyst for the activation of the imine intermediate through hydrogen bonding is described. A mild and operationally simple fragment coupling procedure was accomplished with a wide range of aldehydes as well as amines in good to excellent yields. In addition, the S-benzyl isothiouronium chloride catalyst was easily recovered by simple filtration and reused without any drop in its efficiency.

ChemInform Abstract: An Efficient, Recoverable Fluorous Organocatalyst for Direct Reductive Amination of Aldehydes.

AbstractThe reductive amination procedure in the presence of Hantzsch dihydropyridine as reducing agent and a fluorous thiourea catalyst can be applied to a wide range of substrates.

Single Nucleotide‐Catalyzed Biomimetic Reductive Amination

AbstractWe have successfully developed a single nucleotide (adenosine 5′‐diphosphate)‐catalyzed enantioselective direct reductive amination of aldehydes and ketones using a Hantzsch ester as reducing agent. The process is a simple, efficient and a real mimic of the NADH reduction approach for the synthesis of structurally diverse amines. This reaction is the first report demonstrating the ability of a single nucleotide as catalyst and one of the most genuine biomimetic reactions of organic chemistry.

Efficient and Highly Chemoselective Direct Reductive Amination of Aldehydes using the System Silane/Oxorhenium Complexes

AbstractThis work reports a novel method for direct reductive amination of aldehydes with silanes catalyzed by several high‐valent oxorhenium(V) and oxorhenium(VII) complexes. The catalytic system PhSiH3/ReIO2(PPh3)2 (2.5 mol%) was very efficient for the synthesis of secondary amines and highly chemoselective, tolerating a wide range of functional groups such as NO2, CF3, SO2R, CO2R, F, Cl, Br, I, CN, OH, OCH3, SCH3, NCOR, and double bonds. This novel method was also employed in the synthesis of tertiary amines with moderate yields.

An efficient, recoverable fluorous organocatalyst for direct reductive amination of aldehydes

A commercially available perfluorooctyl aniline and phenyl isothiocyanate were reacted under mild conditions to give 1-[4-(perfluorooctyl)phenyl]-3-phenylthiourea as an analogue of thiourea-based organocatalyst. This fluorous organocatalyst was successfully employed to direct reductive amination of aldehydes. It could be readily separated from reaction product by fluorous solid phase extraction for direct use.

Gallium(III) Triflate Catalyzed Direct Reductive Amination of Aldehydes

Direct hydroamination of aldehydes and ketones provides one-step entry into desired α-aminoalkane derivatives which are important synthons for many biologically active molecules. The reductive amination of aldehydes in the presence of silanes has been effectively promoted by Ga(OTf)3 as a catalyst. Mild conditions, easy work-up and high purity of products with excellent yields are the major advantages of this method.

Direct reductive amination of aldehydes and ketones mediated by a thiourea derivative as an organocatalyst

The direct reductive arylamination of arylaldehydes and ketones has been achieved using a selective imine activation by a hydrogen bond of a thiourea derivative. This mild, acid- and metal-free process requires a catalytic amount of N,N'-bis[3,5-bis(trifluoromethyl)phenyl]thiourea, the Hantzsch 1,4-dihydropydine diethyl 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate as hydride source and activated 5Å-molecule sieve as dehydrant. The method is adaptable for the synthesis of various amines.