Diastereo- and Enantioselective Metathesis Dimerization/Kinetic Resolution of Racemic Planar-Chiral Vinylferrocenes.

Diastereo- and enantioselective kinetic resolution of racemic planar-chiral 1-<i>R</i>-2-vinylferrocenes (<i>rac</i>-<b>1</b>) was attained by the molybdenum-catalyzed asymmetric metathesis dimerization (AMD). Two sequential AMD reactions of <i>rac</i>-<b>1a</b> (R = Br) provided (<i>E</i>)-(<i>S</i>,<i>S</i>)-1,2-di(2-bromoferrocenyl)ethylene in &gt;99% ee, which was converted to (<i>S</i>,<i>S</i>)-1,2-bis[(2-diphenylphosphino)ferrocenyl]ethane (<i>S</i>,<i>S</i>)-<b>5</b>. Planar-chiral bisphosphine (<i>S</i>,<i>S</i>)-<b>5</b> coordinated to a dichloropalladium(II) fragment in a <i>trans</i>-chelating fashion, which was applied as a chiral ligand in the palladium-catalyzed asymmetric allylic alkylation showing enantioselectivity of up to 90% ee.