US EPA

8345830 

Journal Article 

Mechanisms of 1,1-Reductive Elimination from Palladium 

Gillie, A; Stille, JK 

1980 

Yes 

Journal of the American Chemical Society
ISSN: 0002-7863
EISSN: 1520-5126 

102 

15 

4933-4941 

English 

10.1021/ja00535a018 

The 1,1-reductive elimination of ethane from three cis-bis(phosphine)dimethylpalladium complexes, L2Pd(CH3)2 (L = PPh3,PPh2CH3; L2 = Ph2PCH2CH2PPh2), and three trans analogues [L = PPh3, PPh2CH3; L2 = 2,11-bis(diphenylphosphinomethyl) benzo[c]phenanthrene (TRANSPHOS)] was carried out. The three cis complexes underwent reductive elimination in the presence of coordinating solvents (Me2SO, DMF, THF). The trans complexes which could isomerize to cis (L = PPh3, PPh2CH3) did so in polar solvents and then underwent reductive elimination. (TRANSPHOS)dimethy[palladium would not undergo reductive elimination of ethane, even at 100 °C in Me2SO. The eliminations from the cis isomers were intramolecular as determined by the lack of crossover with the perdeuteriomethylpalladium analogue and displayed first-order kinetics (k = 1.04 X 10-3 s-1, L = PPh3, 60 °C; K = (6.5-9.5) X 10-5 s-1, L = PPh2CH3, 60 °C; k = 4.78 X 10-7 s-1, L2 = Ph2PCH2CH2PPh2, 80 °C). The presence of diphenylacetylene in the reaction mixture traps the palladium(O) product as the bis(diphenylmethylphosphine)(diphenylacetylenejpaliadium complex. Although (TRANSPHOS)áimethylpaladium would not undergo a 1,1-reductive elimination of ethane, the addition of CD3I to a Me2SO solution of this complex at 25 °C rapidly produced CD3-CH3, implicating a transient palladium(IV) intermediate. © 1980, American Chemical Society. All rights reserved.