R. Kuwano et al., Synthesis of a trans-chelating chiral diphosphine ligand with only planar chirality and its application to asymmetric hydrosilylation of ketones, TETRAHEDR L, 40(7), 1999, pp. 1327-1330
Optically active diphosphine (S,S)-2,2 "-bis[(diethylphosphino)methyl]-1,1
"-biferrocene (abbreviated to (S,S)-EtTRAP-H) was synthesized from ferrocen
yloxazoline derived from L-valinol in 47% overall yield. The new chiral lig
and, (S,S)-EtTRAP-H, which coordinates to a rhodium atom in a trans-chelati
ng manner, was effective for asymmetric hydrosilylation of ketones to give
optically active secondary alcohols with up to 94% ee. (C) 1999 Elsevier Sc
ience Ltd. All rights reserved.