A PS-DES immobilized ruthenium carbene: a robust and easily recyclable catalyst for olefin metathesis
摘要:
The butyldietliylsilyl polystyrene (PS-DES) supported ruthenium carbene 7 is a robust, practical and easily recyclable catalyst for olefin metathesis of substituted olefins. (C) 2002 Published by Elsevier Science Ltd.
Reductive Coupling of Allylic Esters with Carbonyl Compounds Mediated by the Mischmetall/[SmI2/Pd0cat.′]cat. System
作者:Sédami Médégan、Florence Hélion、Jean-Louis Namy
DOI:10.1002/ejoc.200500291
日期:2005.11
“two-stage catalysis” has been carried out using SmI2 and Pd(PPh3)4 in catalytic amounts together with mischmetall (an alloy of the light lanthanides) as a co-reductant. A catalytic scheme that takes into account previously reported reactions of SmI2/Pd0cat. and mischmetall/SmI2,cat. systems is proposed. It has also been shown that palladium complexes catalyse the addition of organolanthanide species
Mischmetall, an alloy of the light lanthanides, has been used in a variety of organicreactions, either as a coreductant in samarium(II)-mediated reactions (Barbier and Grignard-type reactions, pinacoliccouplingreactions) or as the promoter of Reformatsky-type reactions. It has been also employed as the starting material for easy syntheses of lanthanide trihalides, the reactivity of which has been
Indium(I) iodide was found to mediate in the Barbier allylation and in the Reformatsky reaction of aldehydes and ketones to give homoallylic alcohols and β-hydroxy esters, respectively, presumably via allylindium(III) diiodide.
achieved by the use of samarium diiodide in catalytic amounts together with mischmetall (an alloy of the light lanthanides) as a coreductant. Plausible catalytic schemes are proposed. In addition, organocerium and -lanthanum reagents have been obtained from samarium diiodide catalysed reactions between organic halides and cerium or lanthanum metal, giving a newroute to organolanthanoid compounds. It also