Synthesis of both Enantiomers of Hemiesters by Enantioselective Methanolysis of Meso Cyclic Anhydrides Catalyzed by α-Amino Acid-Derived Chiral Thioureas
作者:Rubén Manzano、José M. Andrés、María-Dolores Muruzábal、Rafael Pedrosa
DOI:10.1021/jo100792r
日期:2010.8.6
ureas and thioureas derived from l- or d-valine act as bifunctionalorganocatalysts able to induce the enantioselectivealcoholysis of mono-, bi-, and tricyclic meso anhydrides. The desymmetrization occurs in near quantitative yields and excellent enantiomeric ratios (up to >99:<1) under low catalyst loading. Both enantiomers of the hemiesters can be directly obtained by changing the configuration of the
We describe the desymmetrization of meso-glutaric anhydrides to chiral hemiesters using a bench-stable homodinuclear Ni-2-(Schiff base) complex as the catalyst in good to excellent yield (up to 99%) and enantioselectivity (up to 94%). Using the opposite enantiomer of the catalyst, we obtained the same yield and enantioselectivity with the opposite configuration, thereby gaining access to both hemiester enantiomers.