Sustainable radical reduction through catalyzed hydrogen atom transfer reactions (CHAT-reactions)
作者:Andreas Gansäuer、Matthias Otte、Frederik Piestert、Chun-An Fan
DOI:10.1016/j.tet.2009.03.088
日期:2009.6
system with coupled catalytic cycles is described that allows radicalreduction by catalyzed hydrogenatomtransfer (CHAT) from transition metal hydrides. These intermediates are generated through H2 activation. Radical generation is carried out by titanocene catalyzed electron transfer to epoxides. The reaction provides a novel entry into the atom-economical reduction of radicals that has long been
Two new catalytic systems for hydrogen‐atom transfer (HAT) catalysis involving the N−H bonds of titanocene(III) complexes with pendant amide ligands are reported. In a monometallic system, a bifunctional catalyst for radical generation and reduction through HAT catalysis depending on the coordination of the amide ligand is employed. The pendant amide ligand is used to activate Crabtree's catalyst to
presented. While the potentially attractive cyclopentadienes gave only moderate yields of the desired alcohols, substituted, nontoxic, and commercially available 1,4-cyclohexadienes, e.g. γ-terpinene, in combination with more elaborate catalysts gave better or similar results than the much more expensive and carcinogenic 1,4-cyclohexadiene. In the practically important reactions of Sharpless epoxides
Sustainable Radical Reduction through Catalytic Hydrogen Atom Transfer
作者:Andreas Gansäuer、Chun-An Fan、Frederik Piestert
DOI:10.1021/ja801232t
日期:2008.6.1
A system with coupled catalytic cycles is described that allows radicalreduction by hydrogenatom abstraction from rhodium hydrides. These intermediates are generated from H2 activation by Wilkinson's catalyst. Radical generation is carried out by titanocene-catalyzed electron transfer to epoxides.
Catalytic, Highly Regio- and Chemoselective Generation of Radicals from Epoxides: Titanocene Dichloride as an Electron Transfer Catalyst in Transition Metal Catalyzed Radical Reactions