Table 1 Epoxidation of various alkenes promoted by Ag(TPIP) in the
presence of isobutyraldehyde and oxygen in dichloroethane
least-squares analysis using anisotropic thermal parameters for all non-
hydrogen atoms. H atoms were located on a difference Fourier map,
and their coordinates were refined as free atoms with an overall
Yield Yield
acid epoxide furan pyran
Yield Yield
isotropic thermal parameter. 9260 reflections, with F
to solve and refine the structure to R = 0.0338 and R
o
> 3s(F
w
o
) were used
= 0.0324, 708
Entry Alkene (mmol)
t/h
(%)
(%)
(%)
(%)
least-squares parameters. The programs used were CRYSTALS and
CAMERON.2
4,25
a
b
c
Cyclooctene (0.77)
Oct-1-ene (0.64)
Cholesteryl acetate (0.59)
Cholesteryl acetate (0.59)
Linalool (0.57)
4
20
0.5 50
2
3
98
98
100
40
58
100
26
5
Crystal data: C100
H
=
92
O
10
N
4
P
8
Ag
4
, M = 2189, triclinic, space group P1,
16.200(5) Å, a 74.22(2),
a
=
12.424(2), b
13.563(2), c
=
=
b
3
23
b = 69.06(2), g = 71.24(2)°, U = 2375(1) Å , Z = 1, D
c
= 1.53 g cm
.
80
70
99
85
CCDC 182/629.
‡ Selected data: H NMR (C
1
d
e
f
30
85
15
4
10
6
D
6
) d 7.97 (m, 8 H), 6.97 (m, 12 H), 3.43 (q,
). Analysis. Calc.: C, 54.87; H, 4.22; N,
Linalool (0.57)
21
6
0.5 H, OCH
2
), 1.02 (t, 0.75 H, CH
3
c
Linalool (5.7)
65
2.42. Found: C, 54.24; H, 4.22; N, 2.56%.
a
) = 1 atm, room temp.; aldehyde/alkene = 7; catalyst = 1 mol%. b
P(O
2
1 I. Rodriguez, C. Alvarez, J. Gomez-Lara, R. Soriano-Garcia and
R. A. Toscano, Lanthanide–Actinide Res., 1986, 1, 253.
2 C. Alvarez, N. Goasdoue, N. Platzer, I. Rodriguez and H. Rudler,
J. Chem. Soc., Chem. Commun., 1988, 1002.
c
a/b isomers: 32/68. Linalool (1 ml), aldehyde (4 ml), catalyst (50 mg),
dichloroethane (20 ml).
3
C. Alvarez, L. Barkaoui, N. Goasdoue, J. C. Daran, N. Platzer, H. Rudler
and J. Vaissermann, J. Chem. Soc., Chem. Commun., 1989, 1507.
as an example of a trinuclear complex in which the silver atoms
adopt both a linear and a tetrahedral coordination,19 the central
planar dinuclear structure with the two linear Ag moieties
found in the present complex is, to the best of our knowledge,
unique.
Preliminary results of the catalytic properties of this complex
in the oxidation of alkenes are promising. Many transition
metals bearing various groups (usually b-diketonato ligands)
are active in the aerobic co-oxidation of alkenes and aldehydes
into epoxides and acids. However, one major problem is linked
to the high rate of oxidation of the aldehyde to the acid: in such
cases, the conversion of the alkenes into epoxides drops
considerably, unless a large excess of aldehyde is used. We have
now found that on the one hand that the lanthanide complexes
4 N. Platzer, H. Rudler, C. Alvarez, L. Barkaoui, B. Denise, N. Goasdoue,
2
M. N. Rager, J. Vaissermann and J. C. Daran, Bull. Chem. Soc. Fr.,
1
995, 132, 95.
5
6
L. Barkaoui, M’hamed Charrouf, M. N. Rager, B. Denise, N. Platzer and
H. Rudler, Bull. Chem. Soc. Fr., 1997, 134, 165.
H. Rudler, B. Denise and J. Ribeiro Gregorio, manuscript in prepara-
tion.
P. A. Kilty and W. M. H. Sachtler, Catal. Rev., 1974, 10, 1.
T. Yamada, T. Takai, O. Rhode and T. Mukaiyama, Bull. Chem. Soc.
Jpn., 1991, 64, 2109.
7
8
9 T. Takai, E. Hata, T. Yamada and T. Mukaiyama, Bull. Chem. Soc. Jpn.,
1991, 64, 2513.
1
0 D. F. Evans and J. N. Tucker, J. Chem. Soc., Chem. Commun., 1975,
2
05.
1
1
1 T. J. Wenzel and R. E. Sievers, J. Am. Chem. Soc., 1982, 104, 382.
2 R. J. Lancashire, in Comprehensive Coordination Chemistry, ed. S. G.
Wilkinson, vol. 5, p. 775.
(
Pr, Eu, Dy) containing TPIP can be used for the epoxidation of
alkenes: their activity are comparable to that of more classical
complexes of Co and Mn. On the other hand, as shown in Table
6
1
1
3 D. R. Whitcomb and R. D. Rogers, Polyhedron, 1997, 16, 863.
4 H. N o¨ th, Z. Naturforsch., Teil B, 1982, 37, 1491.
1
, a series of alkenes gave, in the presence of Ag(TPIP), the
corresponding epoxides (and their rearrangement products for
15 J. V. Nef, Liebigs Ann. Chem., 1893, 277, 68.
20
linalool ) in yields and rates comparable to, or even higher than
those observed for other metal TPIP complexes and also for the
more classical metal b-diketonates (M = Mn, Co).
16 R. West and R. Riley, J. Inorg. Nucl. Chem., 1958, 5, 295.
17 B. Lippert and D. Neugebauer, Inorg. Chim. Acta, 1980, 46, 171.
18 K. B. Yatsimirsky, G. C. Talanova, E. A. Nazarova, M. I. Kabachnik,
T. A. Mastryukova, I. M. Aladzheva, I. V. Leont’eva, M. Yu Antipin
and Yu. T. Struchbov, Koord. Khim., 1993, 19, 469.
8,9,21,22
Although cyclooctene and cholesteryl acetate (entries a and c)
are readily oxidized alkenes, the result achieved with Ag(TPIP)
is striking since high rates and quantitative conversions into the
epoxide are observed. However, and as for other catalysts, the
results were rather sluggish for monosubstituted terminal
alkenes (entry b). Finally, for linalool, the conditions could be
1
2
9 F. Guay and A. L. Beauchamp, J. Am. Chem. Soc., 1979, 101, 6260.
0 D. Felix, A. Melera, J. Seibl and E. sz. Kovats, Helv. Chim. Acta, 1963,
9
6, 1513.
2
1 S. Bennett, S. M. Brown, G. Conole, M. Kessler, S. Rowling, E. Sinn
and S. Woodward, J. Chem. Soc., Dalton Trans., 1995, 367.
varied in order to obtain either the epoxides or their rearrange-
22 A. Atlamsani, E. Pedreza, C. Potvin, E. Dumprey, O. Mohammedi and
ment products20 (entries d–f).
J. M. Br e´ geault, C.R. Acad. Sci. Paris, 1993, 317, 757.
2
3 G. M. Sheldrick, SHELXS-86, Program for Crystal Structure Solution,
University of G o¨ ttingen, 1986.
Footnotes and References
2
4 D. J. Watkin, C. K. Prout, J. R. Carruthers and P. W. Betteridge, Crystals
Issue 10, Chemical Crystallography Laboratory, University of Oxford,
1996.
†
X-Ray structure determination: X-ray quality crystals were obtained by
slow evaporation of CH Cl from a solution of the silver complex in
CH Cl –EtOH. Data were collected at room temperature on a Nonius
2
2
2
2
25 D. J. Watkin, C. K. Prout and L. J. Pearce, CAMERON, Crystallography
Laboratory, University of Oxford, 1996.
CAD4 diffractometer. Empirical absorption correction using PSISCAN was
applied. Anomalous dispersion terms and correction of secondary extinc-
2
3
tion were applied. The structure was solved by SHELXS and refined by
Received in Cambridge, UK, 3rd September 1997; 7/06430F
2300
Chem. Commun., 1997