Lanthanide compounds, alkene hydrogenation

Although transition metal-mediated P-H addition across ordinary alkenes proceeds well only with five-membered cyclic hydrogen phosphonates, addition across the olefinic linkage of a,P-unsaturated compounds occurs readily with a range of phosphorus species and catalytic agents. Of particular note are the reaction systems involving platinum,96-107 palladium,108-115 and the lanthanides.116-122... 

Lanthanide metals are interesting as starting materials to prepare various divalent or trivalent lanthanide derivatives by reaction with or-ganic compounds, this point will not be detailed here and information can be found in ref. (10). It is well known that lanthanide metals can give intermetallic compounds with various metals (Co, Ni, Mg,..) which are able to absorb large quantities of hydrogen. Recently some of these hydride alloys were found to be able to reduce alkynes, mono and di-sub-stituted alkenes to saturated hydrocarbons (12). Some reactions performed with LaNi H at 0 C and then room temperature in THF-MeOH (2 3) are listed below ... 

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