Iridium-catalysed amine alkylation with alcohols in water

Abstract

Amines have been directly alkylated with alcohols using 1 mol% [Cp*IrI(2)](2) catalyst in water in the absence of base or other additives.

Lactic acid and hydrogen from glycerol via acceptorless dehydrogenation using homogeneous catalysts

“…Here the primary and secondary alcohol is dehydrogenated to a carbonyl compound that react with an amine to form imines which are in situ reduced to give the corresponding amines. [29][30][31][32] Similarly to the acceptorless dehydrogenation, substantial progress was made recently in the development of molecular organometallic catalysts for the conversion of alcohols via the borrowing hydrogen strategy, which will have great potential in the benign valorisation of biomass feedstocks. [33][34][35][36] It is worth mentioning that the occurrence of the two pathways (dehydrogenative coupling and release of H 2 or hydrogen borrowing), illustrated in scheme 2 is strongly dependent on the catalytic system.…”

Direct Amination of Secondary Alcohols Using Ammonia

“…[12] One example of an iridium-catalyzed amine alkylation has been reported wherein no additives are required, and it proceeds in water. [13] Williams and co-workers refer to this process as the "borrowing hydrogen methodology". [14] So far, no catalytic systems that are able to aminate secondary alcohols with NH 3 to solely form primary amines have been described.…”

Highly Efficient and Selective Catalytic N‐Alkylation of Amines with Alcohols in Water

“…In most cases, the reaction is performed in organic solvents, which may become problematic, owing to their toxicological properties and the formation of waste products after the reaction. A breakthrough in terms of an ecologically benign solvent was recently made by the groups of Williams [12] and Yamaguchi [13] who reported on the first transition metal catalyzed N-alkylation in water. A precondition for this achievement was the availability of water soluble and stable iridium complexes such as the SCRAM catalyst [Cp*IrI 2 ] 2 [14] and [Cp*Ir(NH 3 ) 3 ]I 2 , respectively ( Figure 1).…”

“…As a typical example, the reaction of a-phenylethylamine with npropanol in the presence of 1 mol % catalyst is illustrated in Scheme 2, which proceeds in nearly quantitative yield. [12] The reaction is performed at reflux temperature. As substrates anilines, benzylamines and primary alkylamines were condensed with equimolar amounts of primary and secondary alcohols giving secondary amines in up to 98 % isolated yield.…”