Asymmetric Radical Reaction in the Coordination Sphere. III. Asymmetric Addition of Trichloromethanesulfonyl Chloride and Carbon Tetrachloride to Olefins Catalysed by a Ruthenium(II) Complex with Chiral Ligand

Article abstract of DOI:10.1246/bcsj.60.3687

The asymmetric addition of trichloromethanesulfonyl chloride to styrene in the presence of a catalytic amount of ruthenium(II) complex with chiral ligands, Ru2Cl4<(-)-diop>3 or Ru2Cl4<(+)-diop>3, proceeds under mild conditions to give optically active 1:1 adducts, 1,1,1,3-tetrachloro-3-phenylpropane (2), with the extrusion of sulfur dioxide.When (-)-DIOP or (+)-DIOP was used as a chiral ligand of the ruthenium(II) complex, (R)-(+)-(2) or (S)-(-)-(2), was obtained with about 10percent enantiomeric excess, respectively.A reaction mechanism involving a radical redox transfer mechanism was proposed; the asymmetric induction was attributed to the restricted configuration of the radical intermediates confined in the coordination sphere of the ruthenium complex with chiral ligands.