Kinetics of the Oxidative Addition of ortho-Substituted Aryl Halides to Palladium(0) Complexes

Abstract

The rate constant of the oxidative addition of ortho-substituted aryl halides, o-ZCH 2 −C 6 H 4 −X [X = I, Br; Z = OMe, NEt 2 , N(CH 2 ) 5 ] to Pd 0 (PPh 3 ) 4 or to Pd 0 (dba)(dppp) generated from Pd 0 (dba) 2 and 1 equiv. of dppp is determined. The oxidative addition is slower for ortho-substituted aryl halides than for the corresponding nonsubstituted or meta-substituted aryl halides. The ortho substituents investigated here do not participate in the oxidative addition by a preliminary complexation of the active Pd 0 (PPh 3 ) 2 or Pd 0 (dppp) complex. The [a]