Influence of the cation in hypophosphite-mediated catalyst-free reductive amination
Natalia Lebedeva1,2, Fedor Kliuev1,3, Olesya Zvereva1,3
1A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, INEOS, Vavilova St. 28, Moscow, 119334, Russia.
None:
Reducing agents with phosphorus-hydrogen bond, such as sodium hypophosphite, phosphite, and hypophosphorous acid are commercially available in bulk amounts, however, their usage is understudied in organic processes. While NaH2PO2 has proved to be an efficient four-electron reductant in the catalyst-free reductive amination, the influence of cation in hypophosphite salt has not been studied yet. This issue is a fundamentally important factor. In the present work, the reactivity of the hypophosphites of alkali metals (Li, K, Rb, and Cs) in reductive amination was explored for the first time. A set of secondary and tertiary amines was synthesized from various types of carbonyl compounds and amines. The remedy for Parkinson's disease, piribedil, was obtained in high yield. The plausible mechanism of the elaborated process was proposed and supported by DFT calculations.
Related Concept Videos
Preparation of Amines: Reductive Amination of Aldehydes and Ketones
Preparation of Amines: Reduction of Amides and Nitriles
Amides can be reduced to primary, secondary, and tertiary amines using catalytic hydrogenation, active metals like Fe,...
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Nitriles to Amines: LiAlH4 Reduction
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Preparation of Amines: Reduction of Oximes and Nitro Compounds
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...

![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
