title: Phosphine-phosphite ligands: chelate ring size vs. activity and enantioselectivity relationships in asymmetric hydrogenation.
abstract: A series of new phosphine-phosphite ligands P(C)(n)OP (n = 1-4) have been synthesized and used for rhodium-catalyzed asymmetric hydrogenation of prochiral olefins in order to study the effect of the chelate ring size. Excellent ees (up to 97.5%) were obtained in the hydrogenation of dimethyl itaconate and an increase of activity and enantioselectivity was observed in the hydrogenation of (Z)-α-acetamidocinnamic acid methyl ester with the increasing length of the backbone of the ligands.
authors: Department of Organic Chemistry, University of Pannonia, H-8200 Veszprém, Egyetem u. 10, Hungary.
authors: Gergely
authors: G
authors: Farkas
authors: Szabolcs
authors: S
authors: Balogh
authors: József
authors: J
authors: Madarász
authors: Áron
authors: Á
authors: Szöllősy
authors: Ferenc
authors: F
authors: Darvas
authors: László
authors: L
authors: Ürge
authors: Maryse
authors: M
authors: Gouygou
authors: József
authors: J
authors: Bakos