New chiral 2,2′:6′,2-terpyridines as ligands for asymmetric catalysis:: cyclopropanation and hydrosilylation reactions

A number of new chiral 2,2':6',2-terpyridines were prepared and the corresponding rhodium and ruthenium complexes were assessed as chiral catalysts for the enantioselective hydrosilylation of acetophenone with diphenylsilane and for the cyclopropanation of styrene with ethyl diazoacetate. Enantioselectivities up to 59% in the cyclopropanation and np to 13% in the hydrosilylation were obtained. (C) 2001 Published by Elsevier Science Ltd.