Chiral 2,2′-bipyridines, 5,6-dihydro-1,10-phenanthrolines and 1,10-phenanthrolines as ligands for enantioselective palladium catalyzed allylic substitution

A number of chiral 5,6-dihydro-1,1-phenanthrolines, 5,6-dihydrobenzo[b]-1,1-phenanthrolines and 5,6,7,8-tetrahydro-2-quinolinylquinoline derived from (-)-pinocarvone were prepared and assessed in the enantioselective palladium catalyzed allylic alkylation of 1,3-diphenylprop-2-enyl acetate with dimethyl-malonate. The introduction of a benzo-fused substituent on the pyridine ring not containing the chiral backbone resulted in the drastic reduction of the stereoselectivity of the reaction. Enantioselectivities up to 81% were obtained. (C) 2000 Published by Elsevier Science Ltd.