Asymmetric Induction via the Structural Indenyl Effect

Constrained geometry,
planar chiral, dichloro­[η5:κS-indenyl-sulfanyl]rhodium complex (pS)-1 reacts with (E)-2-pentene
in the presence of silver hexafluoroantimonate to afford syn,syn-1,3-dimethyl-π-allyl complex (pS)-2 in 88% yield. Reaction of (pS)-2 with the sodium or tetrabutylammonium salts of dimethyl
malonate anion provided dimethyl 2-[(1R,2E)-1-methyl-2-buten-1-yl]-1,3-propanedioate ((R)-3) in 68–70% yield and 66–68% enantiomeric
excess. NMR analysis and density functional theory calculations establish
that asymmetric induction is substantially determined by the electronic
asymmetry of the indenyl ligand polarizing the preferred site of nucleophilic
attack on the π-allyl ligand toward the terminal carbon that
is syn to the indenyl benzo-ring.