Asymmetric Reduction of Ketones by Biocatalysis Using Clementine Mandarin (Citrus reticulata) Fruit Grown in Annaba or by Ruthenium Catalysis for Access to Both Enantiomers

摘要

Biocatalytic reduction of prochiral ketones using freshly ripened clementine mandarin (Citrus reticulata) in aqueous medium is reported. High enantioselectivities were observed, especially for the bioreduction of indanone 3, tetralone 4, and thiochromanone 5 with respectively 95%, 99%, and 86% enantiomeric excess (ee). Enantioselective bio- and metal-catalyzed reactions were compared. Chiral ruthenium catalysts afforded good asymmetric inductions (>75% ee) in most cases, enantiomeric excesses depending on the nature of substrate and ligand. N-aminoindanol prolinamide L-3 was revealed as the best ligand for most ketones. Interestingly, for several substrates both enantiomers could be obtained using either Citrus reticulata or ruthenium complex. Chirality 27:205-210, 2015. (c) 2014 Wiley Periodicals, Inc.