621-45-4Relevant articles and documents
Group 6 Metal Carbonyl Complexes Supported by a Bidentate PN Ligand: Syntheses, Characterization, and Catalytic Hydrogenation Activity
Faust, Kirill,Topf, Christoph,Vielhaber, Thomas
, p. 4535 - 4543 (2020/12/23)
We report on the preparation of a series of phosphorus-nitrogen donor ligand complexes [M(CO)4(PN)], where M = Cr, Mo, W and PN is 2-(diphenylphosphino)ethylamine. The organometallic compounds were readily obtained upon reacting the respective metal hexacarbonyls with equimolar amounts of the pertinent ligand in the presence of tetraethylammonium bromide. The PN-ligated metal carbonyls were fully characterized by standard spectroscopic techniques and X-ray crystallography. The ability of the title compounds to function as homogeneous hydrogenation catalysts was probed in the reduction of acetophenone and benzaldehyde derivatives to yield the corresponding alcohols. The reaction setup was easily assembled by simply combining the components in the autoclave on the bench outside an inert-gas-operated glovebox system.
A Straightforward Deracemization of sec-Alcohols Combining Organocatalytic Oxidation and Biocatalytic Reduction
Liardo, Elisa,Ríos-Lombardía, Nicolás,Morís, Francisco,González-Sabín, Javier,Rebolledo, Francisca
supporting information, p. 3031 - 3035 (2018/06/27)
An efficient organocatalytic oxidation of racemic secondary alcohols, mediated by sodium hypochlorite (NaOCl) and 2-azaadamantane N-oxyl (AZADO), has been conveniently coupled with a highly stereoselective bioreduction of the intermediate ketone, catalyzed by ketoreductases, in aqueous medium. The potential of this one-pot two-step deracemization process has been proven by a large set of structurally different secondary alcohols. Reactions were carried out up to 100 mm final concentration enabling the preparation of enantiopure alcohols with very high isolated yields (up to 98 %). When the protocol was applied to the stereoisomeric rac/meso mixture of diols, these were obtained with very high enantiomeric excesses and diastereomeric ratios (95 % yield, >99 % ee, >99: 1 dr).
Unveiling the Hidden Performance of Whole Cells in the Asymmetric Bioreduction of Aryl-containing Ketones in Aqueous Deep Eutectic Solvents
Vitale, Paola,Abbinante, Vincenzo Mirco,Perna, Filippo Maria,Salomone, Antonio,Cardellicchio, Cosimo,Capriati, Vito
supporting information, p. 1049 - 1057 (2017/03/31)
In this contribution, we report the first successful baker's yeast reduction of arylpropanones using deep eutectic solvents (DESs) as biodegradable and non-hazardous co-solvents. The nature of DES [e.g. choline chloride/glycerol (2:1)] and the percentage of water in the mixture proved to be critical for both the reversal of selectivity and to achieve high enantioselectivity on going from pure water (up to 98:2 er in favour of the S-enantiomer) to DES/aqueous mixtures (up to 98:2 er in favour of the R-enantiomer). As a result, both enantiomers of valuable chiral alcohols of pharmaceutical interest were prepared from the same biocatalyst by simply switching the solvent. The possible inhibition of some (S)-oxidoreductases making part of the genome of such a wild-type whole cell biocatalyst when DESs are used as co-solvents may pave the way for an anti-Prelog reduction. The scope and limitations of this kind of biotransformations for a range of aryl-containing ketones are also discussed. (Figure presented.).
