Relevance of cis- and trans-dichloride Ru intermediates in Grubbs-II olefin metathesis catalysis (H(2)IMesCl(2)Ru=CHR)

Using density functional theory with the B3LYP and M06 functionals, we show conclusively that the (H(2)IMes)(Cl)(2)Ru olefin metathesis mechanism is bottom-bound with the chlorides remaining trans throughout the reaction, thus attempts to effect diastereo- and enantioselectivity should focus on manipulations that maintain the trans-dichloro Ru geometry.