Tandem enantioselective organo- and biocatalysis:a direct entry for the synthesis of enantiomerically pure aldols

摘要

Direct proline-catalyzed aldol reactions were linked in sequence with lipase-catalyzed kinetic resolutions to afford enantiomerically pure (>99% ee) aldol adducts in higher conversion than a standard resolution of racemic materials.The combination of organocatalytic aldol reactions and enzymatic kinetic resolutions provided exclusively either the (R)- or (S)-enantiomer of the aldol adducts even though an (R)-selective lipase catalyzed the kinetic resolutions.Furthermore,the one-pot tandem reactions are inexpensive,are operationally simple,circumvents the use of organic solvent and are environmentally benign.