Preparation and application of bisoxazoline ligands with a chiral spirobiindane skeleton for asymmetric cyclopropanation and allylic oxidation
作者:Bin Liu、Shou-Fei Zhu、Li-Xin Wang、Qi-Lin Zhou
DOI:10.1016/j.tetasy.2006.02.010
日期:2006.2
A new type of bisoxazoline ligand 4 (abbreviated as SpiroBOX) containing a chiral spirobiindane scaffold were easily prepared in high yields from enantiornerically pure 1,1'-spirobiindane-7,7'-diol (SPINOL) with 1,1'-spirobiindane-7,7'-dicarboxylic acid as the key intermediate. Ligands 4 were applied to the Cu-catalyzed asymmetric cyclopropanation of styrenes with menthyl diazoacetate and allylic oxidation of cyclic alkenes with tert-butyl perbenzoates. The copper complexes of ligands 4 showed high activities and moderate to good enantioselectivities. (c) 2006 Elsevier Ltd. All rights reserved.