Mechanism of the stille reaction. 2. Couplings of aryl triflates with vinyltributyltin. Observation of intermediates. A more comprehensive scheme

AL Casado, P Espinet, AM Gallego

Index: Casado; Espinet; Gallego Journal of the American Chemical Society, 2000 , vol. 122, # 48 p. 11771 - 11782

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Citation Number: 143

Abstract

The mechanism of the [PdL4]-catalyzed couplings between R-OTf (R= pentahalophenyl; L= PPh3, AsPh3) and Sn (CH CH2) Bu3 has been studied. The addition of LiCl favors the coupling for L= AsPh3 in THF but retards it for L= PPh3. Separate experiments show that for L= AsPh3, LiCl accelerates the otherwise very slow and rate-determining oxidative addition of the aryl triflate to [PdL4], leading to trans-[PdRClL2]. Therefore, the overall process is ...