A new catalytic procedure for atom-transfer radical addition (ATRA) and cyclization (ATRC) reactions is described. The combination of the ruthenium(III) complex [RuCl(2)Cp*(PPh3)] (Cp*: pentamethylcyclopentadienyl) with magnesium allows these reactions to be performed under mild conditions with high efficiency. In most cases, the catalyst concentrations required are significantly lower than those used
Ruthenium vs. Osmium Complexes as Catalysts for Atom Transfer Radical Addition Reactions
作者:Mariano A. Fernández‐Zúmel、Gregor Kiefer、Katrin Thommes、Rosario Scopelliti、Kay Severin
DOI:10.1002/ejic.201000388
日期:2010.8
evaluated for atomtransferradicaladdition (ATRA) and cyclization (ATRC) reactions. The Os complex enabled these reactions to be performed with similar efficiency as that of the analogous Ru complex [Cp*RuCl2(PPh3)]. The olefin complex [Cp*OsBr(H2C=CHPh)(PPh3)] was obtained by reduction of [Cp*OsBr2(PPh3)] with Mg in the presence of an excess of styrene, whereas an analogous Ru complex was not observed
Atom-Transfer Radical Addition Reactions Catalyzed by RuCp* Complexes: A Mechanistic Study
作者:Mariano A. Fernández-Zúmel、Katrin Thommes、Gregor Kiefer、Andrzej Sienkiewicz、Katarzyna Pierzchala、Kay Severin
DOI:10.1002/chem.200901396
日期:2009.11.2
gain information about the mechanism of atom‐transferradicalreactions catalyzed by the complexes [RuCl2Cp*(PPh3)] and [RuClCp*(PPh3)2] (Cp*=pentamethylcyclopentadienyl), in the presence and in the absence of the reducing agent magnesium. The reactions of styrene with ethyl trichloroacetate, ethyl dichloroacetate, or dichloroacetonitrile were used as test reactions. The results show that for substrates