Pergamon Tetrahedron: Asymmetry 9 (1998) 2279–2284
TETRAHEDRON:
ASYMMETRY
New optically active amido-phosphinite ligand and ruthenium
complexes
Pierre Le Gendre, Martin Offenbecher, Christian Bruneau
*
and Pierre H. Dixneuf
*
Laboratoire de Chimie de Coordination et Catalyse, UMR 6509: CNRS, Université de Rennes, Campus de Beaulieu,
35042 Rennes, France
Received 7 April 1998; accepted 29 May 1998
Abstract
The hydrogenation of acetoacetanilide in the presence of optically active ruthenium catalysts leads to 3-
hydroxy-N-phenylbutanamide in good yield and high enantioselectivity (ee>95%). Its direct phosphinylation with
chlorodiphenylphosphine affords a new bifunctional amido-phosphinite ligand that can easily be coordinated to
[(arene)RuCl
2
] and to the CpRuCl(PPh
3
) moiety with very good stereoselectivity from CpRuCl(PPh
3
)
2
. © 1998
Elsevier Science Ltd. All rights reserved.
1. Introduction
Efficient asymmetric catalysis in the presence of metal complexes requires the utilization of functional
mono- or polydentate optically active ligands. A breakthrough in this area was the preparation of a variety
of chiral diphosphine ligands with C
2
symmetry.
1
Unsymmetrical ligands and molecules containing two
different phosphorus chelating groups have also found useful applications in enantioselective hydro-
genation of olefins, ketones and imines associated with transition metals such as rhodium, ruthenium
or iridium.
2
Recently, new heterobidentate P–O,
3
P–N,
2d,3,4
P–S
5
ligands exhibiting efficient stereo-
induction properties have appeared. It has also been shown that phosphinite ligands have potential in
asymmetric hydrovinylation of olefins,
6
dimerization of dienes,
7
hydrocyanation,
8
allylic substitution,
9
and hydrogenation of C–C double bonds
10
and ketones.
11
We report here the synthesis of a new amido-
phosphinite ligand and its use in the preparation of new ruthenium complexes.
*
Corresponding authors. E-mail: christian.bruneau@univ-rennes1.fr
0957-4166/98/$ - see front matter © 1998 Elsevier Science Ltd. All rights reserved.
PII: S0957-4166(98)00223-7
tetasy 2372 Article