Efficient asymmetric hydrogenation of olefins with hydrazine-derived diphosphoramidites.
Enantiopure, BINOL-derived diphosphoramidites built upon an achiral hydrazine spacer are efficient ligands for the hydrogenation of 2-(acetylamino)-3-(aryl)-propenoic methyl esters. The activity and enantioselectivity of the hydrazine derivatives were shown to be markedly influenced by the nature of the two NR substituents, symmetrical but bulky R groups leading to the best results. A diphosphosphoramidite obtained from (t)BuHNNH(t)Bu resulted in ee's as high as 95%. The present results contradict previous reports on "short" diphosphoramidites.
Eberhardt
Luc
L
Laboratoire de Chimie Inorganique Moléculaire, Institut de Chimie, UMR 7177 CNRS and Université Louis Pasteur, 1 rue Blaise Pascal, F-67008, Strasbourg, Cedex, France.
Armspach
Dominique
D
Matt
Dominique
D
Oswald
Benoît
B
Toupet
Loic
L
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D006834:Hydrazines / Q000737:chemistry*; D006865:Hydrogenation; D008024:Ligands; D009284:Naphthols / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*; D013237:Stereoisomerism
D000475:Alkenes; C406944:BINOL, naphthol; D006834:Hydrazines; D008024:Ligands; D009284:Naphthols; D009943:Organophosphorus Compounds; C434331:phosphoramidite