%0 Nanopartikel unedler Metalle (Mg0, Al0, Gd0, Sm0) %A Wildemann, H. %E Dünkelmann, P. %E Müller, M. %E Schmidt, B. %I American Chemical Society %D 2003 %C S.l. %G Record converted from VDB: 12.11.2012 %B Journal of Organic Chemistry %@ 0022-3263 %T A short olefin metathesis-based route to enantiomerically pure arylated dihydropyrans and a,ß-unsaturated delta-Valero lactones %U http://dx.doi.org/10.1021/jo0264729 %U http://juser.fz-juelich.de/record/28590/files/22684.pdf %U http://juser.fz-juelich.de/record/28590/files/22684.jpg?subformat=icon-1440 %U http://juser.fz-juelich.de/record/28590/files/22684.jpg?subformat=icon-180 %U http://juser.fz-juelich.de/record/28590/files/22684.jpg?subformat=icon-640 %X The synthesis of arylated dihydropyrans and unsaturated lactones starting from enantiomerically pure alpha-hydroxy ketones (prepared by an enzyme-catalyzed benzoin condensation) is described. The key steps are a highly diastereoselective addition of vinyl metal compounds under chelate control and a ruthenium-catalyzed ring-closing olefin metathesis reaction. Elucidation of the relative configuration of the final products was achieved by NOE experiments.