syn-Selective Direct Catalytic Asymmetric Mannich-Type Reactions of Aromatic and Heteroaromatic Hydroxy Ketones Promoted by Y[N(SiMe3)2]3/Linked-BINOL Complexes

Full details of syn-selective catalytic asymmetric direct Mannich-type reactions of aromatic and heteroaromatic hydroxy ketones promoted by Y[N(SiMe3)2]3/linked-BINOL complexes are described. From a screening of various rare-earth metals and linked-BINOL derivatives, a Y[N(SiMe3)2]3/TMS-linked-BINOL (1.7/1) complex was determined to be the most effective. Mannich-type reactions of aromatic and heteroaromatic hydroxy ketones with aryl and alkenyl N-diphenylphosphinoylimines, catalyzed by 0.1 molar amount of Y[N(SiMe3)2]3 and 0.059 molar amount of TMS-linked-BINOL, afforded syn-β-amino-α-hydroxy ketones in good yields (78–98%), high diastereoselectivity (syn/anti = 81/19–96/4), and high enantioselectivity (86–98% ee).