1412894-90-6Relevant articles and documents
Mechanism of Ni-Catalyzed Reductive 1,2-Dicarbofunctionalization of Alkenes
Lin, Qiao,Diao, Tianning
, p. 17937 - 17948 (2019/11/05)
Ni-catalyzed cross-electrophile coupling reactions have emerged as appealing methods to construct organic molecules without the use of stoichiometric organometallic reagents. The mechanisms are complex: plausible pathways, such as "radical chain" and "sequential reduction" mechanisms, are dependent on the sequence of the activation of electrophiles. A combination of kinetic, spectroscopic, and organometallic studies reveals that a Ni-catalyzed, reductive 1,2-dicarbofunctionalization of alkenes proceeds through a "sequential reduction" pathway. The reduction of Ni by Zn is the turnover-limiting step, consistent with Ni(II) intermediates as the catalyst resting-state. Zn is only sufficient to reduce (phen)Ni(II) to a Ni(I) species. As a result, commonly proposed Ni(0) intermediates are absent under these conditions. (Phen)Ni(I)-Br selectively activates aryl bromides via two-electron oxidation addition, whereas alkyl bromides are activated by (phen)Ni(I)-Ar through single-electron activation to afford radicals. These findings could provide insight into achieving selectivity between different electrophiles.
Water control over the chemoselectivity of a Ti/Ni multimetallic system: Heck- or reductive-type cyclization reactions of alkyl iodides
Millan, Alba,Alvarez De Cienfuegos, Luis,Miguel, Delia,Campana, Araceli G.,Cuerva, Juan M.
supporting information, p. 5984 - 5987 (2013/02/23)
A versatile Ti/Ni multimetallic protocol is described for the efficient catalysis of two different reactions, namely a Heck- and reductive-type cyclization of alkyl iodides, in the absence or presence of water, respectively. Noteworthy, the versatility of
