Reductive Elimination Reaction of trans- and cis-Diorganobis (tertiary phosphine) palladium (II) Complexes

Abstract

Series of trans- and cis-diorganopalladium(II) complexes, trans- and cis-PdRR'L₂ (R, R'=alkyl and/or aryl groups L=tertiary phosphine ligands) have been prepared, and their reductive elimination reactions and reactions with organic iodides examined in detail. The following features emerge from the studies. (a) For reductive elimination to take place the two organic groups must be situated in mutually cis positions. (b) trans-Diorganopal-ladium complexes isomerize to their cis isomers prior to reductive elimination. (c) Ease of reductive elimination varies depending on the ligands and organic groups. (d) Aryl groups reductively eliminate more easily than alkyl groups. (e) In the presence of organic iodides trans-diorganopalladium complexes are isomerized to their cis isomers, the process being catalyzed by monoorganopalladium species generated in the systems. (f) cis-Dime-thylpalladium(II) probably forms a Pd(IV) species on interaction with organic iodides and reductive elimination proceeds from the organopalladium(IV) intermediate. On the other hand, cis-PdMe(Ar)L₂ complexes afford MeAr without participation of organic iodides.