Av. Bedekar et Pg. Andersson, A NEW CLASS OF BIS-OXAZOLINE LIGANDS FOR THE CU-CATALYZED ASYMMETRIC CYCLOPROPANATION OF OLEFINS, Tetrahedron letters, 37(23), 1996, pp. 4073-4076
A set of new chiral bis-oxazolines, 5a-b and 6a-c, has been synthesise
d from D and L-diethyl 2,3-O-isopropylidene tartrates and chiral amino
alcohols. These ligands were found to be efficient in the Cu(I)-catal
ysed asymmetric cyclopropanation of olefins. Bis-oxazolines of this ty
pe based on readily available valine were found comparable with previo
us ligands based on the more expensive ten-leucine. (C) 1996 Elsevier
Science Ltd.