YTTERBIUM TRICYANIDE - PREPARATION AND CATALYTIC ACTIVITY FOR THE ADDITION OF CYANOTRIMETHYLSILANE TO CARBONYL-COMPOUNDS

Ytterbium tricyanide was obtained quantitatively by the reaction of ytterbium tri-isopropoxide with cyanotrimethylsilane. The addition of cyanotrimethylsilane to various carbonyl compounds was catalyzed effectively by ytterbium tricyanide to proceed under mild conditions giving the adducts in high selectivities. 2-Methylcyclohexanone yielded the adduct in a highly diastereoselective manner and the reagent system also effectively gave the adducts from easily enolizable ketones as well as from acid-sensitive ones. alpha,beta-Unsaturated ketones and aldehydes afforded 1,2-adducts exclusively.