Multiple mechanistic pathways for zirconium-catalyzed carboalumination of alkynes. Requirements for cyclic carbometalation processes involving CH activation

E Negishi, DY Kondakov, D Choueiry…

Index: Negishi, Ei-Ichi; Kondakov, Denis Y.; Choueiry, Daniele; Kasai, Kayoko; Takahashi, Tamotsu Journal of the American Chemical Society, 1996 , vol. 118, # 40 p. 9577 - 9588

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Citation Number: 144

Abstract

The reactions of internal and terminal alkynes with organoalanes containing Et, n-Pr, and i- Bu groups in the presence of Cp2ZrCl2 and MeZrCp2Cl were investigated with the goal of clarifying mechanistic details of some representative cases. Three fundamentally different processes, ie,(i) CM bond addition without CH activation in the alkyl group,(ii) cyclic CM bond addition via CH activation, and (iii) hydrometalation, have been observed, and the ...