Coupled chemoenzymatic transfer hydrogenation catalysis for enantioselective reduction and oxidation reactions

Water‐Soluble Phenanthroline Complexes of Rhodium, Iridium and Ruthenium for the Regeneration of NADH in the Enzymatic Reduction of Ketones

“…As there is a risk of slow hydrolysis in water, the aqueous solutions are immediately filtered, and the filtrates are concentrated to dryness to give the analytically pure salts [1][2][3][4]Cl. All compounds have been characterised by 1 H and 13 C NMR spectroscopy, mass spectroscopy and elemental analysis.…”

“…In light of the findings by Steckhan [22] and Schmid [1] on organometallic NADH regeneration for enzymatic ketone reductions, we studied the chemoenzymatic enantioselective transfer hydrogenation of 4-phenylbutan-2-one and acetophenone in aqueous solution. We used the NADH-dependent enzymes horse liver alcohol dehydrogenase (HLADH) or alcohol dehydrogenase from Rhodococcus sp.…”

“…The enzymatic transfer hydrogenation reactions of acetophenone or 4-phenylbutan-2-one (33 mm) were carried out in phosphate buffer (1 mL, pH 7) at 37°C with 1 unit of alcohol dehydrogenase S-ADH or HLADH respectively, in the presence of NAD + (1 mm) and [1]Cl as NADH-regenerating catalyst and NaHCO 2 (100 mm) as the hydrogen source. The reactions without rhodium catalyst were performed with NADH instead of NAD + (40 mm), and the reactions without enzymatic reduction were performed without enzyme and NAD + .…”

“…[1] The transition-metal-based enantioselective hydrogenation or transfer hydrogenation of ketones in organic solvents [2][3][4][5][6][7][8][9][10] as well as in aqueous solutions [11][12][13][14][15][16][17][18][19][20][21] is one of the most commonly used synthetic approaches. Biotransformations of organic substrates by various enzymes have also found widespread applications, particularly because of their capability to efficiently perform enantioselective transformations.…”

“…coupled with [(η 5 -C 5 Me 5 ) Rh(bipy)(OH 2 )] 2+ -promoted regeneration of NADH, which allowed the reduction of 3-methylcyclohexanone with an enantiomeric excess up to 97 %. [1] In this paper we report a series of water-soluble rhodium, iridium and ruthenium complexes containing 1,10-phenanthroline or its 5-substituted analogues as chelating N,N-donor ligands and the catalytic potential of these complexes for the regeneration of NADH in the chemoenzymatic re-duction of ketones. The electrochemical behaviour of the complexes is also discussed.…”