Samarium diiodide and other lanthanide iodides are very efficient Lewis aci
d catalysts for numerous reactions such as Mukaiyama aldol and Michael reac
tions, preparation of enoxysilanes, cycloaddition reactions and ring openin
g of oxiranes by silylated nucleophiles or amines. Activities and selectivi
ties of catalysts vary with the nature of the metal and the ligands for som
e reactions. Lanthanide iodides coordinated by a cyclopentadienyl ligand wi
th an asymmetric center and an ether function on a pendant chain have been
characterized and tested for catalysis: low enantioselectivities are observ
ed for complexes with intramolecular coordination. (C) 1998 Elsevier Scienc
e S.A. All rights reserved.