Kinetic studies, alkyl electrophile oxidative addition

Kinetics studies of the oxidative addition of a variety of unactivated primary alkyl electrophiles to several PdL2 complexes (L=trialkylphosphine) have been described [46]. For the reaction depicted in Eq. 17, the activation parameters are AU =20.8 kcal mol" (20 °C) AH =2A kcal mol" AS =-63 eu. The large negative AS" value that is observed is consistent with an associative pathway for oxidative addition. The rate of addition increases as the solvent polarity increases, as would be expected for the postulated 8 2 mechanism, and is not affected by added P(f-Bu)2Me, indicating that the alkyl bromide oxidatively adds to PdL2 (not PdLi or PdL3) [47]. 

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