Highly Enantioselective Isomerization of 4,7-Dihydro-1,3-dioxepins Catalyzed by Me-DuPHOS-Modified Dihalogenonickel Complexes and Determination of the Absolute Configuration of the Isomerization Products This work was supported by the Fonds der Chemische Industrie. We would like to thank Prof. Dr. H. Brunner, Universität Regensburg, for help in questions concerning analytical data. Me-DuPHOS=1,2-bis(2,5-dimethylphospholanyl)benzene