Mucopolysaccharasen

Gibian, Heinz

doi:10.1007/978-3-662-30541-6_29

Cited by 1 publication

(1 citation statement)

References 104 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Product 4, resulting from the dimerization of 1, is a common indication of radical intermediates. 15 Although the C-C bond formed in 4 could have also arisen from reductive elimination from a dialkyl Ni species, the increased yield of 4 with bulkier neocuproine suggests that the formation of 4 does not involve metal and competes with the Ni-mediated pathway to generate 2. The convergence of the stereocenter for cisand trans-5 upon cyclization is consistent with formation of a radical intermediate erasing the substrate stereoinformation.…”

Section: Substrate Probesmentioning

confidence: 99%

Mechanism of Ni-Catalyzed Reductive 1,2-Dicarbofunctionalization of Alkenes

2019

View full text Add to dashboard Cite

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 1,2dicarbofunctionalization 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.

show abstract

Section: Substrate Probesmentioning

confidence: 99%