pubs.acs.org/joc
Synthesis of both Enantiomers of Hemiesters by Enantioselective Methanolysis of Meso Cyclic Anhydrides Catalyzed by r-Amino Acid-Derived Chiral Thioureas† Ruben Manzano, Jose M. Andres, Marı´ a-Dolores Muruz abal, and Rafael Pedrosa* Instituto CINQUIMA and Departamento de Quı´mica Org anica, Facultad de Ciencias, Universidad de Valladolid, Dr. Mergelina s/n, 47011-Valladolid, Spain
[email protected] Received June 11, 2010
Both ureas and thioureas derived from L- or D-valine act as bifunctional organocatalysts able to induce the enantioselective alcoholysis of mono-, bi-, and tricyclic meso anhydrides. The desymmetrization occurs in near quantitative yields and excellent enantiomeric ratios (up to >99:
