Synthesis of monodentate chiral spiro phosphonites and the electronic effect of ligand in asymmetric hydrogenation.
New monodentate chiral phosphonites were synthesized from enantiomerically pure 1,1'-spirobiindane-7,7'-diol. The phosphonites 2 were efficient ligands for the Rh-catalyzed asymmetric hydrogenation of alpha- and beta-dehydroamino acid derivatives, providing the amino acids in high enantioselectivities. The study of electronic effect showed that the electron-withdrawing substitutent on the P-phenyl ring of the phosphonite ligand dramatically decreased both the reactivity and enantioselectivity of the ligand.
Fu
Yu
Y
State Key Laboratory and Institute of Elemento-organic Chemistry, Nankai University, Tianjin 300071, China.
Hou
Guo-Hua
GH
Xie
Jian-Hua
JH
Xing
Liang
L
Wang
Li-Xin
LX
Zhou
Qi-Lin
QL