Furanoside phosphite–phosphoroamidite: new ligand class for the asymmetric nickel-catalyzed trialkylaluminium addition to aldehydes
摘要:
We have described the first successful application of bidentate ligands in the asymmetric Ni-catalyzed trialkylaluminium addition to several aldehydes. The ligands are prepared from inexpensive D-(+)-xylose and D-(+)-glucose and have the advantage of carbohydrate and phosphite/phosphoroamidite moieties. After systematic variation of the position of the phosphoroamidite group at either C5 or C-3, the configuration of C-3 and the substituents in the biaryl phosphite/phosphoroamidite moieties, enantioselectivities up to 84% and high yields were obtained in the Ni-catalyzed trialkylaluminium addition to several aldehydes. (C) 2009 Elsevier Ltd. All rights reserved.