Abstract
Reactions between Mo(NAr)(CHR)(Me(2)Pyr)-(OTPP) (Ar = 2,6-i-Pr(2)C(6)H(3), R = H or CHCMe(2)Ph, Me(2)Pyr = 2,5-dimethylpyrrolide, OTPP = O-2,3,5,6-Ph(4)C(6)H) and CH(2)=CHX where X = B(pin), SiMe(3), N-carbazolyl, N-pyrrolidinonyl, PPh(2), OPr, or SPh lead to Mo(NAr)(CHX)-(Me(2)Pyr)(OTPP) complexes in good yield. All have been characterized through X-ray studies (as an acetonitrile adduct in the case of X = PPh(2)). The efficiencies of metathesis reactions initiated by Mo(NAr)(CHX)(Me(2)Pyr)(OTPP) complexes can be rationalized on the basis of steric factors; electronic differences imposed as a consequence of X being bound to the alkylidene carbon do not seem to play a major role. Side reactions that promote catalyst decomposition do not appear to be a serious limitation for Mo=CHX species.