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Vinylation of Aldehydes Using Mn/Cr Alloy and a N 4 ‐Ligand/Ni II ‐Catalyst
Author(s) -
Harnying Wacharee,
Berkessel Albrecht
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201500024
Subject(s) - catalysis , ligand (biochemistry) , chelation , chemistry , alloy , alcohol , medicinal chemistry , silylation , bipyridine , chromium , inorganic chemistry , organic chemistry , crystal structure , receptor , biochemistry
We report an efficient and practical protocol for the Cr/Ni‐catalyzed vinylation of aldehydes, based on the use of Mn/Cr alloy (ca. 10 % Cr) and TMSCl. No additional Cr salts need to be added. In the presence of NiCl 2 (0.3 mol %) and a bis(ketimino)‐2,2′‐bipyridine as N 4 ‐chelating ligand (1 mol %), the vinylations proceed smoothly at room temperature. The presence of catalytic amounts of MeOH and LiOAc as additives was found to further promote the efficiency of the catalytic system, even in the absence of the ligand. Detailed reaction monitoring revealed that LiOAc accelerates the product alcohol silylation, thus increasing the turnover rate.