New chiral 2,2′-bipyridine diols as catalysts for enantioselective addition of diethylzinc to benzaldehyde
作者:Hoi-Lun Kwong、Wing-Sze Lee
DOI:10.1016/s0957-4166(99)00399-7
日期:1999.9
New C-2-symmetric chiral 2,2'-bipyridine diols were prepared from readily available homochiral materials such as menthone and camphor. Their catalytic activities in the reaction of diethylzinc with benzaldehyde to give 1-phenyl-1-propanol were studied. In all cases, the yields were good and enantioselectivities up to 95% were observed. (C) 1999 Elsevier Science Ltd. All rights reserved.
Enantiomerically pure pyridine and 2,2′-bipyridine thioethers: new N–S chiral ligands for asymmetric catalysis. Palladium-catalyzed allylic alkylation
Diastereomeric pure pyridine and 2,2'-bipyridine thioethers, derived from (+)-camphor, were prepared and assessed in the enantioselective palladium-catalyzed allylic substitution of 1,3-diphenylprop-2-enyl acetate with dimethyl malonate. Enantioselectivities of up to 76% were obtained. (C) 1999 Elsevier Science Ltd. All rights reserved.