Addition of organolithium compounds to tricarbonyl(tropone)iron complexes: Experimental and structural studies

Article abstract of DOI:10.1016/S0022-328X(02)01725-4

The regioselectivity (1,2 vs. 1,4) in the nucleophilic addition of organolithium reagents to tropone(tricarbonyl)iron complexes has been studied and found to be correlated with the relative hardness of the nucleophile (HSAB principle). X-ray structures of

Full text of DOI:10.1016/S0022-328X(02)01725-4

Journal of Organometallic Chemistry 659 (2002) 176ꢀ185
/
www.elsevier.com/locate/jorganchem
Addition of organolithium compounds to tricarbonyl(tropone)iron
complexes: experimental and structural studies
Yoann Coquerel, Jean-Pierre Depre´s *, Andrew E. Greene, Christian Philouze
LEDSS, Universite´ Joseph Fourier, Baˆtiment Chimie Recherche, 301 Rue de la Chimie, BP 53, 38041 Grenoble, France
Received 22 April 2002; accepted 18 July 2002
Abstract
The regioselectivity (1,2 vs. 1,4) in the nucleophilic addition of organolithium reagents to tropone(tricarbonyl)iron complexes has
been studied and found to be correlated with the relative hardness of the nucleophile (HSAB principle). X-ray structures of several
1,2 and 1,4 adducts are reported. # 2002 Elsevier Science B.V. All rights reserved.
Keywords: Tricarbonyl(tropone)iron complexes; Nucleophilic addition
1. Introduction
regio- and stereoselectively the anti 1,2 addition pro-
ducts, whereas functionalized zincꢀcopper reagents [11],
/
The tricarbonyl(tropone)iron complex (1) is a highly
functionalized and reactive molecule, which has at-
tracted the attention of both inorganic and organic
chemists for more than 40 years. It was initially
generated, together with other organoiron carbonyls,
in the reaction of acetylene with triiron dodecacarbonyl
[1] and can now be synthesized in high yield from
tropone and diiron nonacarbonyl [2]. Its chemical
structure was indicated in 1962 from the hydrogenation
of the iron-free double bond [3] and confirmed two years
later by X-ray diffraction analysis [4]. The tricarbonyl
iron moiety is bonded to the carbon atoms C4 through
C7 of the tropone ring, which leaves the complex 1 with
an enone function. Synthetic transformations of the
complex [5] have generally involved the enone unit,
which manifests the reactivity expected of an isolated
enone [6]. The complex undergoes, for example, a
number of cycloaddition reactions with electron rich
(and electron deficient) partners; in addition, various
nucleophilic reagents add to the complex. Organo-
K-Selectride† [6], and soft nucleophiles such as malonic
carbanions [6] have been found to give the anti 1,4
addition products. We report herein complementary
observations on the nucleophilic addition of organome-
tallic reagents (mainly organolithium) to the tricarbo-
nyl(tropone)iron complex 1 and three of its derivatives
(complexes 4, 7, and 10). X-ray diffraction analysis of
these complexes and four representative adducts is also
reported.
2. Results and discussion
During recent research in our laboratory on synthetic
applications of the tricarbonyl(tropone)iron complex
(1), we observed that the regioselectivity (1,2 vs. 1,4
adducts) in the nucleophilic addition of organolithium
reagents to the complex was surprisingly dependent on
the nature of the nucleophile R (Scheme 1). These
results, as well as studies on the effect of changes in the
solvent, counterion, and temperature, are summarized
lithium [6ꢀ8] and organomagnesium [6,7,9] reagents,
/
as well as sodium borohydride in the presence of
cerium(III) chloride [6,10], have been reported to give
in Tables 1ꢀ4.
/
As can been seen in Table 1, the regioselectivity of the
reaction appears, to a degree, to reflect the size of the
nucleophile: small nucleophiles (entries 1, 2) gave
efficiently the 1,2 addition products, whereas the bulkier
ones (entries 5, 6) provided in high yield mainly or
* Corresponding author. Tel.:
76514982
E-mail address: jean-pierre.depres@ujf-grenoble.fr (J.-P. Depre´s).
ꢁ
/
33-4-76514345; fax:
ꢁ/33-4-
0022-328X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 1 7 2 5 - 4

Y. Coquerel et al. / Journal of Organometallic Chemistry 659 (2002) 176ꢀ
/
185
177
the regioselectivity of the addition of organolithium
compounds to complex 1 may, in fact, be better
explained by the HSAB principle [12] than by steric
factors. Small alkyllithium reagents are known to be
harder than those branched, and aryl- and alkynyl-
lithium reagents are considered harder than the alkyl
reagents.
Scheme 1.
exclusively the 1,4 adducts. The regio- and stereochemi-
cal outcomes of the reactions of the complex with
phenyllithium (entry 3) and tert-butyllithium (entry 6)
were established by X-ray diffraction analysis (Figs. 1
and 2). From the X-ray structure of complex 1 (Fig. 3),
it can be seen, however, that there is no significant steric
difference on the anti face between the two electrophilic
carbon atoms C1 and C3. This observation suggests that
The regioselectivity of the reaction is somewhat
influenced by the nature of the solvent (Table 2). The
best solvents for this reaction are toluene and ether. The
use of more polar, complexing solvents favored, as
expected, conjugate addition, but to the detriment of the
yield. It is noteworthy that the reaction of the complex
with ButLi in the presence of HMPA (entry 6) did not
yield the expected addition product, but the tricarbo-
Table 1
Nucleophilic addition of organolithium compounds to complex 1. Regioselectivity as a function of the nucleophile.
a
b
Entry
RLi
Conditions
Products
Yield (%)
Ratio 2:3
c
1
2
3
4
5
6
MeLi
Prn CꢀCꢀ
PhLi
Bun Li
Bus Li
But Li
Et2O, ꢂ85 8C
Et2O, ꢂ85 8C
Toluene, ꢂ85 8C
Et2O, ꢂ85 8C
Et2O, ꢂ85 8C
Et2O, ꢂ85 8C
2a:3a
2b:3b
2c:3c
2d:3d
95
90
100:0
100:0
100:0
85:15
33:67
d
/
Li
e
99
89
68
64
f
2e:3e
2f:3f
g
0:100
a
Based on isolated, homogeneous products.
b
c
d
e
f
The ratio of the two regioisomers has been determined by NMR analysis of the crude mixture and confirmed by isolation of the products.
Seventy-three percent in Ref. [8] and quant. in Ref. [7].
Based on 12% of complex 1 recovered.
Yield not given in Ref. [7].
Complexes 2e and 3e were isolated as 1:1 mixtures of diastereomers.
Trace amount of alcohol 2f (B1% by NMR) was detected.
g
Table 2
Nucleophilic addition of organolithium compounds to complex 1. Regioselectivity as a function of the solvent.
a
b
Entry
RLi
Conditions
Products
Yield (%)
Ratio 2:3
1
2
3
4
5
6
Bun Li
Bun Li
Bun Li
Bun Li
Bun Li
But Li
Toluene, ꢂ85 8C
Et2O, ꢂ85 8C
THF, ꢂ85 8C
THFꢁDME (70%), ꢂ85 8C
THFꢁHMPA (10%), ꢂ85 8C
Et2OꢁHMPA (10%), ꢂ85 8C
2d:3d
2d:3d
85
89
69
47
25
21
87:13
85:15
69:31
75:25
62:38
2d:3d
2d:3d
2d:3d
3g (RꢃH)
ꢀ/
a
Based on isolated, homogeneous products.
The ratio of the two regioisomers was determined by NMR analysis of the crude mixture and/or isolation of the products.
b
Table 3
Nucleophilic addition of organolithium and organomagnesium compounds to complex 1
a
b
Entry
RM
Conditions
Products
Yield (%)
Ratio 2:3
1
2
3
4
MeLi
MeMgBr
Bun Li
Bun MgBr
Et2O, ꢂ85 8C
Et2O, ꢂ85 8C
Et2O, ꢂ85 8C
Et2O, ꢂ85 8C
2a:3a
2a:3a
2d:3d
2d:3d
95
78
89
76
100:0
100:0
85:15
80:20
a
Based on isolated, homogeneous products.
The ratio of the two regioisomers was determined by NMR analysis of the crude mixture and confirmed by isolation of the products.
b

178
Y. Coquerel et al. / Journal of Organometallic Chemistry 659 (2002) 176ꢀ185
/
Table 4
Nucleophilic addition of organolithium compounds to complex 1. Regioselectivity as a function of the temperature.
a
b
Entry
RLi
Conditions
Products
Yield (%)
Ratio 2:3
1
2
3
Bun Li
Bun Li
Bun Li
Et2O, ꢂ85 8C
Et2O, ꢂ35 8C
Et2O, 0 8C
2d:3d
2d:3d
2d:3d
89
98
31
85:15
64:36
35:65
a
Based on isolated, homogeneous products.
The ratio of the two regioisomers was determined by NMR analysis of the crude mixture and/or isolation of the products.
b
Fig. 2. ORTEP-II molecular diagram of 3f.
The tendency for the regioselectivity of the nucleo-
philic addition to reflect the relative hardness of the
organometallic reagent was also found with two C2-
substituted tropone iron complexes. As can be seen in
Table 5, with the tricarbonyl(4,5,6,7-h-2-methoxycyclo-
Fig. 1. ORTEP-II molecular diagram of 2c.
nyl(dihydrotropone)iron complex 3g, which is possibly
formed through reduction by in situ generated iron
carbonylates [13].
Switching the metallic counterion from lithium to
magnesium did not significantly influence the regios-
electivity of the reaction, but did have a deleterious
effect on the yield (Table 3). The use of lithium
homocuprates led only to decomposition products,
which may be the result of decomplexation of the
tropone, observed in a related case [14].
Augmentation of the temperature favored in the case
of n-butyllithium in ether the formation of the 1,4-
adduct, but at 0 8C there was a considerable reduction
in the yield (Table 4).
Fig. 3. ORTEP-II molecular diagram of 1.

Y. Coquerel et al. / Journal of Organometallic Chemistry 659 (2002) 176ꢀ
/
185
179
hepta-2,4,6-trienone)iron complex (4) and the tricarbo-
nyl(4,5,6,7-h-2-methylcyclohepta-2,4,6-trienone)iron
complex (7) (Scheme 2), as with complex 1, hard
nucleophiles gave mostly and exclusively the 1,2 addi-
tion products, whereas soft tert-butyllithium gave
mainly the 1,4 adduct. With the larger nucleophiles,
however, the yields were lower than in the additions to
complex 1 (Table 1), probably due to the increased steric
hindrance from the C2 substituent.
The stereochemistry of complex 9f was determined
unambiguously by X-ray diffraction analysis (Fig. 4),
which showed a trans relationship between the sub-
stituents at C2 (methyl) and C3 (tert-butyl), the latter
being anti to the iron group. Attempts to obtain the
corresponding cis 2,3-disubstituted complex through
addition of tert-butyllithium to complex 1, followed
by enolate quenching with iodomethane, resulted only in
the formation of the non-methylated complex 3f. The
low reactivity of the lithium enolate of 3f can probably
be ascribed to steric factors as the lithium enolate of
complex 3g (Table 2, entry 6) reacted well under the
same conditions [3b].
of the Z and E heptafulvene complexes 13d (R?ꢃ
was formed from dehydration of complex 11d (Rꢃ
(Scheme 3). The complex 11a (RꢃMe) also suffered
dehydration on alumina to give the unstable heptaful-
vene complex 13a (R?ꢃH). Interestingly, the presence
of the triphenylphosphine ligand significantly acceler-
ates these dehydration reactions, since the correspond-
ing tricarbonyl iron complexes 2a and 2d could be
recovered in high yield following similar chromato-
graphic treatment.
/
Prn)
/
Bun)
/
/
The same series of experiments has also been
performed on complex 10 [15], in which the electronic
density on iron has been increased relative to 1 through
substitution of triphenylphosphine for a carbon mon-
oxide ligand. Again, mixtures of 1,2 and 1,4 addition
products (11 and 12, respectively) were obtained in
various proportions as a function of the nucleophile
(Scheme 3 and Table 6). The expected anti addition was
confirmed by X-ray diffraction analysis of complex 12f
(Fig. 5).
Fig. 4. ORTEP-II molecular diagram of 9f.
During the attempted separation of the two isomers
11d and 12d on silica gel or neutral alumina, a mixture
Scheme 2.
Scheme 3.
Table 5
Nucleophilic addition of organolithium compounds to complexes 4 and 7
a
b
c
Entry
Substrate
RLi
Conditions
Products
Yield (%)
Ratio 5:6 or 8:9
1
2
3
4
5
6
4
4
4
4
4
7
MeLi
PhLi
Bun Li
Bus Li
But Li
But Li
THF, ꢂ85 8C
THF, ꢂ85 8C
THF, ꢂ85 8C
THF, ꢂ85 8C
THF, ꢂ85 8C
Et2O, ꢂ85 8C
5a:6a
5c:6c
5d:6d
5e:6e
5f:6f
8f:9f
98
quant.
50
100:0
100:0
89:11
Not determined
B15
0
36
ꢀ/
34:66
a
THF was used because of low solubility of complex 4 in Et2O at ꢂ85 8C.
Based on isolated, homogeneous products except for entry 4.
The ratio of the two regioisomers was determined by NMR analysis of the crude mixture and/or isolation of the products.
b
c

180
Y. Coquerel et al. / Journal of Organometallic Chemistry 659 (2002) 176ꢀ185
/
Table 6
Nucleophilic addition of organolithium compounds to complex 10
a
b
Entry
RLi
Conditions
Products
Yield (%)
Ratio 11:12
1
2
3
MeLi
Bun Li
But Li
THF, ꢂ85 8C
THF, ꢂ85 8C
THF, ꢂ85 8C
11a:12a
11d:12d
11f:12f
quant.
90
60
100:0
69:31
22:78
a
Based on isolated, homogeneous products except for 11a (purityꢀ95% by NMR without purification), 11d (not isolated), and 11f (isolated as a
1:1 mixture of 11f and its decomposition product formed during purification).
b
The ratio of the two regioisomers was determined by NMR analysis of the crude mixture and/or isolation of the products.
Fig. 5. ORTEP-II molecular diagram of 12f.
3. Structural work
In order to augment the structural data available on
tricarbonyl(tropone)iron complexes, X-ray diffraction
Fig. 7. ORTEP-II molecular diagram of 7.
analysis was also performed on complexes 1 (Fig. 3) [16],
4 (Fig. 6), and 7 (Fig. 7). The structure of complex 10
(Fig. 8) has been reproduced here for comparison [15].
3.1. Structure analysis and refinement
The crystals of compounds 1, 2c, 3f, 4, 7, 9f, and 12f
were obtained by the slow evaporation of their chloro-
form solutions. Data collections were performed using
an Enraf-Nonius CAD4 for compounds 2c, 3f, and 9f
and an Enraf-Nonius MACH 3 for compounds 1, 4, 7,
and 12f, both operating with molybdenum radiation
˚
monochromated by a graphite plate (0.71073 A). Data
reductions, refinements, and drawings were performed
using the teXsan software [17]. All structures were
solved using the direct method SIR-92 [18]. Refinements
were performed on F using a full-matrix least-squares
process and anisotropic thermal parameters for all non
H atoms. Crystal data and various other results are
reported in Table 7.
3.2. Discussion
For structures with more than one elemental unit per
cell, only mean values will be cited in the following
discussion. All seven structures reported herein exhib-
ited the distorted-square-pyramidal structure typical of
Fig. 6. ORTEP-II molecular diagram of 4.

Y. Coquerel et al. / Journal of Organometallic Chemistry 659 (2002) 176ꢀ
/
185
181
recrystallized) [2], and 76.5ꢀ
/
77.5 8C (sublimed) [19].
Our sample, recrystallized from ethyl acetate or chloro-
form, exhibited a melting point of 65 8C. In Fig. 3, the
X-ray structure of our material is shown. The observed
¯
space group is P1 (triclinic) with two elemental units per
cell. This structure differs only slightly from that
previously reported (space group: P21/c, monoclinic,
Zꢃ4) [4]. The seven-membered ring of the complex is
/
non-planar, having two planes that intersect with a
dihedral angle of 42.58 (ca. 478 for the previously
reported structure). The shortening of the C5ꢁ
/C6
bond, which is a general phenomenon in this type of
iron complex, is more pronounced in the present
˚
structure of the complex (1.378(4) vs. 1.396(13) A).
In the solid state, there are no significant differences
in bond lengths and angles in the four complexes 1, 4, 7,
and 10 (except for the greater bond-length variations of
the three carbonyl ligands in the C2-substituted com-
plexes than in the parent complex 1). In the solid state
structure of the alcohol complex 2c (Fig. 1), there are
also no significant differences in bond lengths and
angles in the seven-membered ring compared with those
of the parent complex 1. In the structures of the diene
Fig. 8. ORTEP-II molecular diagram of 10.
tricarbonyl(h4-diene)iron complexes. The complex 1
exists in at least two distinct crystalline forms [4].
Indeed, several melting points for this complex have
been reported: 63.5ꢀ
leum ether or benzeneꢀ
(recrystallized from ether or benzene), 70ꢀ
/
64.5 8C (recrystallized from petro-
petroleum ether) [3a], 83ꢀ84 8C
71 8C (not
/
/
complexes 3f (Fig. 2), 9f (Fig. 4), and 12f (Fig. 5), the
˚
C6 single bond is about 0.01 A longer than in the
/
C5ꢁ
/
Table 7
Crystal data and structure refinement parameters for compounds 1, 7, 4, 2c, 3f, 9f, and 12f
Compound
1
7
4
2c
3f
9f
12f
Empirical formula
Formula weight
Temperature (K)
Crystal system
C
10H6FeO4
C11H8FeO4
260.03
293
C11H8FeO5
276.03
293
C16H12FeO4
324.12
293
C14H16FeO4
304.12
293
C15H18FeO4
318.15
293
C31H31FeO3P
538.40
293
246.00
293
Triclinic
Monoclinic
P21/n
Triclinic
¯
Triclinic
¯
Triclinic
¯
Triclinic
¯
Monoclinic
P21/n
¯
Space group
/
P1/
/
P1/
/
P1/
/
P1/
/
P1/
Unit-cell dimensions
˚
a (A)
˚
6.748(4)
11.882(2)
13.087(3)
99.88(2)
101.25(3)
88.56(2)
1013.8(6)
4
12.772(4)
7.700(2)
22.152(5)
90
7.390(2)
14.777(3)
20.667(4)
90.15(2)
96.51(2)
90.69(2)
2242.1(8)
8
11.280(3)
11.730(5)
12.426(4)
86.49(3)
109.60(2)
108.58(3)
1466(1)
4
6.688(4)
8.837(2)
12.439(4)
94.88(2)
104.09(4)
99.85(3)
696.3(5)
2
6.681(5)
8.915(2)
13.108(3)
99.34(2)
95.58(3)
103.17(3)
742.8(6)
2
12.946(3)
15.170(2)
14.002(6)
90
b (A)
˚
c (A)
a (8)
b (8)
92.09(2)
90
97.73(2)
90
g (8)
3
V (A )
˚
2177.1(9)
8
1.377
2725(1)
4
0.641
Z
m (mmꢂ1
)
1.473
1.612
496
1.349
1.635
1120
1.039
1.468
664
1.088
1.450
316
1.023
1.422
332
Dcalc. (g cmꢂ3
F(000)
Dimensions (mm)
)
1.587
1056
1.312
1128
0.25ꢄ
0.18ꢄ0.17
ꢂ10, 9
ꢂ17, 17
0, 19
0.29ꢄ
0.20ꢄ0.15
ꢂ17, 17
0, 10
0.29ꢄ
0.23ꢄ0.18
ꢂ10, 10
ꢂ20, 20
0, 29
0.35ꢄ
0.22ꢄ0.21
ꢂ15, 14
ꢂ16, 16
0, 17
0.40ꢄ
0.30ꢄ0.30
ꢂ9, 9
ꢂ12, 12
0, 17
0.33ꢄ
0.17ꢄ0.15
0, 9
0.32ꢄ
0.28ꢄ0.22
ꢂ18, 18
0, 21
h
k
ꢂ12, 12
ꢂ18, 18
6.16
l
0, 31
20.55
0, 19
0.82
Decay (%)
Reflections
Parameters
Rint
8.57
5644
2.55
7112
2.26
5465
2.13
3455
4775
313
3834
193
6140
325
295
0.027
0.030
813
0.033
0.070
409
0.017
0.060
184
0.017
0.030
0.043
0.040
0.007
0.020
0.01
0.040
Rs
R(F)[17]
wR[18]
Goodness-of-fit
0.0454
0.0423
1.921
0.0557
0.0501
1.913
0.0528
0.0620
1.956
0.0475
0.369
1.892
0.0306
0.0372
1.801
0.0339
0.0540
1.946
0.0377
0.0404
1.793

182
Y. Coquerel et al. / Journal of Organometallic Chemistry 659 (2002) 176ꢀ185
/
parent triene complexes 1, 7, and 10, and, in addition,
˚
the tricarbonyl iron moiety is about 0.02 A closer to the
20 8C. The aqueous layer was extracted twice with
etherꢀpentane (3:1) and the combined organic layers
/
mean plane defined by the four carbon atoms C4, C5,
C6 and C7 in the diene complexes than in the triene
complexes (3f, 1.559(1); 9f, 1.564(1); 1, 1.573(2); 2c,
1.582(2); 4, 1.586(4); 7, 1.571(2)). In the structure of
complex 12f, it is noteworthy that the triphenylpho-
sphine ligand, which is in the basal position anti to the
carbonyl of the tropone ring in the complex 10, is now in
the basal position anti to the tert-butyl substituent of
the tropone ring. This difference in the solid-state
geometry of these two complexes can undoubtedly be
attributed to steric factors.
were washed with water and brine, dried over anhydrous
Na2SO4, and concentrated under vacuum to afford the
crude product, which was purified by flash chromato-
graphy with 4ꢀ10% EtOAc in pentane to give 115 mg
/
(76%) of alcohol complex [22] 2d, followed by 20 mg
(13%) of ketone complex 3d. Filtration of the crude
complex 11a (purityꢀ95% by NMR) over silica gel or
/
neutral alumina gave mainly a dimer of 13a; chromato-
graphy of the crude mixture of 11d and 12d on silica gel
or neutral alumina gave an E/Z mixture of heptafulvene
complexes 13d and the pure dienone complex 12d;
chromatography of the crude mixture of 11f and 12f
over silica gel or neutral alumina led to partial decom-
position of the complex 11f.
4. Conclusion
The regioselectivity of the nucleophilic addition of a
number of organolithium reagents to the tricarbo-
nyl(tropone)iron complex and several of its derivatives
can be explained by the HSAB principle. Relatively hard
nucleophiles yield primarily or exclusively the 1,2
adducts, whereas those that are somewhat softer afford
mainly the 1,4 adducts. Crystallographic data have led
to a number of observations and complement existing
data on these types of complexes.
5.1. cis-Tricarbonyl(h4-1-n-pentynylcyclohepta-2,4,6-
trienol)iron complex (2b)
Oil; IR: 3582, 2055, 1986 cmꢂ1; 1H-NMR (300 MHz):
d 5.85 (dd, Jꢃ
4.9, 3.2 Hz, 1H), 5.40 (pseudo dd, Jꢃ
5.19 (dd, Jꢃ7.0, 1.4 Hz, 1H), 3.58 (pseudo d, Jꢃ
Hz, 1H), 3.04 (t, Jꢃ5.2 Hz, 1H), 2.16 (t, Jꢃ4.7 Hz,
/
7.1, 5.4 Hz, 1H), 5.58 (pseudo dd, Jꢃ
5.3, 3.2 Hz, 1H),
5.3
/
/
/
/
/
/
2H), 2.10 (s, 1H), 1.53 (hex, Jꢃ
/
4.9 Hz, 2H), 0.97 (t, Jꢃ
/
4.9 Hz, 3H); 13C-NMR (75 MHz): d 13.6, 20.9, 22.1,
53.3, 64.3, 69.6, 82.3, 83.5, 83.8, 95.8, 128.0, 128.9, 209.8
5. Experimental
(br); MS (DCI): m/z 297 ([Mꢂ
/
OH]ꢁ, 5%), 230 ([Mꢂ
/
OHꢁNH3ꢂ
/
/
3CO]ꢁ, 100%).
Thin-layer chromatography was performed on Merck
60F254 (0.2 mm) sheets, which were visualized with 4%
molybdophosphoric acid in EtOH. Merck 40-60 silica
gel 60 was employed for column flash chromatography.
A Nicolet 400 spectrophotometer was used to record IR
spectra. A Brucker AC 200 or Avance 300 spectrometer
was employed for the NMR spectra (CDCl3 solutions
with Me4Si as the reference). M.p.s were taken on a
5.2. cis-Tricarbonyl(h4-1-n-butylcyclohepta-2,4,6-
trienol)iron complex (2d)
1
M.p. 43 8C; IR: 3606, 2049, 1973 cmꢂ1; H-NMR
(300 MHz): d 5.84 (dd, Jꢃ
(m, 2H), 5.08 (dd, Jꢃ10.9, 2.1 Hz, 1H), 3.27 (pseudo d,
Jꢃ7.8 Hz, 1H), 2.97 (t, Jꢃ7.8 Hz, 1H), 1.77 (s, 1H),
1.47ꢀ1.72 (m, 2H), 1.06ꢀ1.47 (m, 4H), 0.90 (pseudo t,
Jꢃ
7.0 Hz, 3H); 13C-NMR (75 MHz): d 14.1, 23.0, 26.6,
44.3, 54.2, 71.0, 71.5, 84.3, 94.1, 128.7, 131.3, 210.5 (br);
MS (DCI): m/z 305 ([MH]ꢁ, 3%), 287 ([MꢂOH]ꢁ,
/
10.7, 8.0 Hz, 1H), 5.40ꢀ
/
5.53
/
/
/
Buchi-Tottoli apparatus and are not corrected. Mass
¨
/
/
spectra were obtained on an AEI MS-30 mass spectro-
meter. Microanalysis were performed by the Central
Service of the CNRS. THF, DME, and ether were
distilled from sodium-benzophenone, and HMPA and
toulene from CaH2. All the reactions were carried in dry
glassware and under an Ar atmosphere.
Complexes 1 [2], 4 [3b], 7 [20] and 10 [21] were
prepared by literature procedures. Complexes 2a [7,8],
2c [7], and 3g [19] exhibited physical and spectral
properties identical with those reported in the literature.
The procedure for the addition of n-butyllithium to
complex 1 is representative: To a magnetically stirred
solution of 123 mg (0.50 mmol) of complex 1 in 5 mL of
/
/
100%). Anal. Calc. for C14H16FeO4: C, 55.29; H, 5.30.
Found: C, 55.41; H, 5.30%.
5.3. trans-Tricarbonyl(h4-3-n-butylcyclohepta-4,6-
dienone)iron complex (3d)
Oil; IR: 2060, 1991, 1654 cmꢂ1; 1H-NMR (300 MHz):
d 5.84 (pseudo t, Jꢃ
Hz, 1H), 3.18 (d, Jꢃ
1H), 2.58ꢀ2.72 (m, 1H), 1.96ꢀ
11.9 Hz, 1H), 1.16ꢀ
/
5.9 Hz, 1H), 5.49 (dd, Jꢃ
7.5 Hz, 1H), 3.11 (d, Jꢃ
2.08 (m, 1H), 1.70 (t, Jꢃ
6.7
/
8.0, 5.3
/
/6.6 Hz,
/
/
/
ether at ꢂ
/
85 8C was added dropwise over 20 min 0.44
/
1.53 (m, 6H), 0.89 (pseudo t, Jꢃ
/
mL (1.0 mmol) of a 2.3 M solution of n-butyllithium in
hexane. The solution was then diluted with ether (5 mL),
treated with water (5 mL), and allowed to warm to
Hz, 3H); 13C-NMR (75 MHz): d 14.0, 22.6, 28.5, 41.2,
44.2, 48.0, 57.1, 65.6, 89.6, 90.9, 207.6, 208.8 (br); MS
(DCI): m/z 305 ([MH]ꢁ, 100%).

Y. Coquerel et al. / Journal of Organometallic Chemistry 659 (2002) 176ꢀ
/
185
183
5.4. cis-Tricarbonyl(h4-1-sec-butylcyclohepta-2,4,6-
trienol)iron complex (2e) (1:1 mixture of diastereomers)
5.8. cis-Tricarbonyl(4,5,6,7-h-1-phenyl-2-
methoxycyclohepta-2,4,6-trienol)iron complex (5c)
Oil; IR: 3605, 2049, 1974 cmꢂ1; 1H-NMR (300 MHz):
M.p. 91ꢀ
1H-NMR (300 MHz): d 7.18ꢀ
Jꢃ7.6, 4.5, 1.3 Hz, 1H), 5.18 (d, Jꢃ
(ddd, Jꢃ7.9, 4.5, 1.3 Hz, 1H), 3.40 (s, 3H), 3.33 (pseudo
d, Jꢃ
/
92 8C; IR: 3582, 2050, 1986, 1664 cmꢂ1
7.38 (m, 5H), 5.37 (ddd,
9.1 Hz, 1H), 5.13
;
d 5.80ꢀ
4.99 (m, 1H), 3.10ꢀ
1.84ꢀ1.98 (m, 1H), 1.74 (pseudo s, 2H), 1.32ꢀ
3H), 0.71ꢀ
1.12 (m, 14H); 13C-NMR (75 MHz): d 12.6,
/
5.95 (m, 2H), 5.42ꢀ
/
5.57 (m, 4H), 5.03 (m, 1H),
2.99 (m, 2H),
1.64 (m,
/
/
3.22 (m, 2H), 2.88ꢀ
/
/
/
/
/
/
/
/
7.9 Hz, 1H), 3.27 (pseudo t, Jꢃ8.2 Hz, 1H), 2.93
/
(s, 1H); 13C-NMR (75 MHz): d 53.9, 55.0, 69.9, 75.2,
12.7, 13.2, 14.3, 23.3, 24.9, 46.1, 46.2, 54.3, 54.3, 67.5,
67.7, 74.4, 74.4, 85.2, 85.2, 93.3, 93.3, 129.3, 129.7,
83.0, 92.1, 99.6, 124.6, 127.3, 128.5, 148.4, 156.7, 210.3
OH]ꢁ, 24%), 270 ([Mꢂ
131.1, 131.4, 210.6 (br); MS (FAB): m/z 287 ([Mꢂ
OH]ꢁ, 13%), 259 ([Mꢂ CO]ꢁ, 13%), 231 ([Mꢂ
OHꢂ
OHꢂ OHꢂ
2CO]ꢁ, 21%), 203 ([Mꢂ 3CO]ꢁ, 100%),
([MꢂOHꢂ
Fe(CO)3]ꢁ, 22%).
/
(br); MS (DCI): m/z 337 ([Mꢂ
/
/
OHꢁNH3ꢂ
/
/
3CO]ꢁ, 100%).
/
/
/
/
/
/
/
/
5.9. cis-Tricarbonyl(4,5,6,7-h-1-n-butyl-2-
methoxycyclohepta-2,4,6-trienol)iron complex (5d)
5.5. trans-Tricarbonyl(h4-3-sec-butylcyclohepta-4,6-
dienone)iron complex (3e) (1:1 mixture of
diastereomers)
Oil; IR: 3593, 2046, 1984, 1964, 1661 cmꢂ1; 1H-NMR
(300 MHz): d 5.45 (ddd, Jꢃ8.1, 4.5, 1.3 Hz, 1H), 5.34
(ddd, Jꢃ7.6, 4.6, 1.3 Hz, 1H), 4.91 (d, Jꢃ9.0 Hz, 1H),
3.43 (s, 3H), 3.15 (dd, Jꢃ8.1, 1.2 Hz, 1H), 3.08 (pseudo
t, Jꢃ7.6 Hz, 1H), 2.31 (s, 1H), 1.60ꢀ1.75 (m, 2H),
1.19ꢀ1.46 (m, 3H), 0.80ꢀ
1.04 (m, 4H); 13C-NMR (75
/
/
/
Oil; IR: 2057, 1989, 1660 cmꢂ1; 1H-NMR (300 MHz):
/
d 5.82 (pseudo t, Jꢃ
/
5.9 Hz, 2H), 5.56 (pseudo t, Jꢃ
/
6.9
/
/
Hz, 2H), 3.00ꢀ
/
3.13 (m, 4H), 2.69ꢀ
/
2.83 (m, 2H), 0.75ꢀ
/
/
/
1.92 (m, 22H); 13C-NMR (75 MHz): d 12.6, 12.6, 14.6,
15.8, 26.1, 27.1, 39.4, 41.8, 43.2, 43.4, 52.8, 53.2, 57.2,
57.3, 63.1, 65.0, 90.8, 90.8, 91.0, 91.1, 207.3 (br), 208.5,
208.6, 209.2 (br); MS (DCI): m/z 305 ([MH]ꢁ, 100%).
MHz): d 14.2, 22.9, 26.3, 43.2, 53.9, 54.9, 67.1, 73.4,
83.9, 91.5, 98.2, 156.9, 210.7 (br); MS (DCI): m/z 317
([Mꢂ
/
OH]ꢁ, 22%), 250 ([Mꢂ
/
OHꢁ
/
NH3ꢂ
3CO]ꢁ,
/
100%).
5.6. trans-Tricarbonyl(h4-3-tert-butylcyclohepta-4,6-
dienone)iron complex (3f)
5.10. Tricarbonyl(h4-cis-2-methoxy-trans-3-n-
butylcyclohepta-4,6-dienone)iron complex (6d)
Needles (recrystallized from CHCl3), m.p. 134ꢀ
135 8C; IR: 2060, 1996, 1651 cmꢂ1 1H-NMR (300
MHz): d 5.82 (pseudo t, Jꢃ5.9 Hz, 1H), 5.54 (dd, Jꢃ
7.7, 5.5 Hz, 1H), 3.30 (d, Jꢃ8.0 Hz, 1H), 3.13 (pseudo
d, Jꢃ6.5 Hz, 1H), 2.47 (pseudo dd, Jꢃ12.4, 4.6 Hz,
1H), 2.02ꢀ2.13 (m, 1H), 1.72 (pseudo t, Jꢃ12.2 Hz,
/
Oil; IR: 2061, 1990, 1668 cmꢂ1; 1H-NMR (300 MHz):
d 5.81 (pseudo t, Jꢃ5.9 Hz, 1H), 5.52 (ddd, Jꢃ8.1, 5.1,
0.9 Hz, 1H), 3.26 (s, 3H), 3.02ꢀ3.14 (m, 2H), 2.93 (d,
Jꢃ10.4 Hz, 1H), 2.50ꢀ2.61 (m, 1H), 1.48ꢀ1.76 (m, 3H),
1.24ꢀ1.43 (m, 3H), 0.93 (pseudo t, Jꢃ
6.9 Hz, 3H); 13C-
NMR (75 MHz): d 14.2, 23.0, 27.5, 35.9, 54.4, 55.1,
58.6, 61.0, 83.2, 89.3, 90.6, 205.0, 208.6 (br); MS (DCI):
m/z 335 ([MH]ꢁ, 100%).
;
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
1H), 0.91 (s, 9H); 13C-NMR (75 MHz): d 27.2, 36.4,
39.9, 57.0, 58.1, 61.3, 90.6, 90.9, 207.9, 208.9 (br); MS
(DCI): m/z 305 ([MH]ꢁ, 100%). Anal. Calc. for
C14H16FeO4: C, 55.29; H, 5.30. Found: C, 55.08; H,
5.43%.
5.11. cis-Tricarbonyl(4,5,6,7-h-1-tert-butyl-2-
methylcyclohepta-2,4,6-trienol)iron complex (8f)
5.7. cis-Tricarbonyl(4,5,6,7-h-1-methyl-2-
methoxycyclohepta-2,4,6-trienol)iron complex (5a)
Oil; IR: 3582, 2047, 1976 cmꢂ1; 1H-NMR (200 MHz):
d 5.83 (dq, Jꢃ
1.4 Hz, 1H), 5.34 (ddd, Jꢃ
(dd, Jꢃ8.2, 1.4 Hz, 1H), 3.05 (ddd, Jꢃ
1H), 1.70 (d, Jꢃ
/
8.6, 1.4 Hz, 1H), 5.57 (ddd, Jꢃ
7.5, 4.5, 1.7 Hz, 1H), 3.32
8.9, 7.5, 1.4 Hz,
1.4 Hz, 3H), 1.56 (s, 1H), 1.01 (s, 9H);
/
8.2, 4.1,
1
Oil; IR: 3590, 2049, 1980, 1661 cmꢂ1; H-NMR (300
/
/
/
MHz): d 5.31ꢀ
3.44 (s, 3H), 3.28ꢀ
/
5.37 (m, 2H), 4.86 (d, Jꢃ
/
9.0 Hz, 1H),
9.0
/
/
3.36 (m, 1H), 3.15 (pseudo t, Jꢃ
/
13C-NMR (50 MHz): d 22.3, 27.2, 40.7, 57.5, 72.2, 78.9,
83.8, 93.8, 128.9, 137.1, 210.8 (br); MS (DCI): m/z 301
Hz, 1H), 2.40 (s, 1H), 1.41 (s, 3H); 13C-NMR (75 MHz):
d 32.4, 53.9, 54.8, 69.2, 70.1, 82.9, 92.4, 96.6, 157.7,
([Mꢂ
/
OH]ꢁ, 32%), 234 ([Mꢂ
/
OHꢁ
/
NH3ꢂ
3CO]ꢁ,
/
210.4 (br); MS (DCI): m/z 275 ([Mꢂ
/
OH]ꢁ, 16%), 208
([MꢂOHꢁNH3ꢂ
/
/
/
3CO]ꢁ, 100%).
100%).

184
Y. Coquerel et al. / Journal of Organometallic Chemistry 659 (2002) 176ꢀ185
/
5.12. Tricarbonyl(h4-cis-2-methyl-trans-3-tert-
butylcyclohepta-4,6-dienone)iron complex (9f)
5.16. trans-Dicarbonyltriphenylphosphine(h4-3-tert-
butylcyclohepta-4,6-dienone)iron complex (12f)
Prisms (recrystallized from CHCl3), m.p. 100ꢀ
102 8C; IR: 2062, 1999, 1648 cmꢂ1 1H-NMR (200
MHz): d 5.71 (pseudo t, Jꢃ5.8 Hz, 1H), 5.58 (pseudo
dd, Jꢃ6.9, 4.1 Hz, 1H), 3.27 (pseudo d, Jꢃ6.2 Hz,
2H), 2.15 (dd, Jꢃ8.2, 2.7 Hz, 1H), 1.85ꢀ2.03 (m, 1H),
1.10 (d, Jꢃ
6.9 Hz, 3H), 1.02 (s, 9H); 13C-NMR (50
MHz): d 18.0, 29.5, 37.9, 43.6, 59.7, 60.0, 62.1, 89.6,
91.4, 207.9, 209.1 (br); MS (DCI): m/z 319 ([MH]ꢁ,
100%).
/
Prisms (recrystallized from CHCl3), m.p. 194ꢀ
(dec.); IR: 1989, 1934, 1632 cmꢂ1 1H-NMR (200
MHz): d 7.31ꢀ7.57 (m, 15H), 4.38ꢀ5.06 (m, 2H),
2.76ꢀ2.88 (m, 1H), 2.52ꢀ2.71 (m, 2H), 1.91ꢀ2.06 (m,
1H), 1.60 (pseudo t, Jꢃ
11.7 Hz, 1H), 0.75 (s, 9H); 13C-
NMR (75 MHz): d 27.2, 36.0, 39.8, 55.9, 58.8, 90.8,
91.7, 128.4, 128.6, 130.2, 130.2, 133.1, 133.2, 134.0,
134.6, 209.0, 215.9 (br), 217.8 (br); MS (DCI): m/z 539
([MH]ꢁ, 100%).
/
196 8C
;
;
/
/
/
/
/
/
/
/
/
/
/
/
5.17. The dimer of dicarbonyltriphenylphosphine(h4-
heptafulvene)iron complex (13a)
5.13. cis-Dicarbonyltriphenylphosphine(h4-1-
methylcyclohepta-2,4,6-trienol)iron complex (11a)
1
Not isolated pure; IR: 1978, 1915 cmꢂ1; H-NMR
Unstable solid; IR: 3589, 1974, 1915 cmꢂ1; 1H-NMR
(200 MHz): d 7.30ꢀ
9.1 Hz, 2H), 5.43 (pseudo d, Jꢃ
(m, 2H), 4.92 (pseudo s, 2H), 4.70ꢀ
(pseudo t, Jꢃ7.3 Hz, 2H), 2.46 (pseudo t, Jꢃ
2H); 13C-NMR (75 MHz) highly complex spectrum; MS
(DCI): m/z 723 ([2MꢁHꢂPPh3ꢁ
CO]ꢁ, 7%), 665
(23%), 583 ([2MꢁHꢂPPh3ꢂ Hꢂ
4CO]ꢁ or [2Mꢁ
Fe(CO)2PPh3]ꢁ, 16%), 479 ([MH]ꢁ, 2%), 431 ([2Mꢁ
Hꢂ Hꢂ2PPh3ꢂ
2PPh3]ꢁ, 24%), 349 ([2Mꢁ 3CO]ꢁ,
13%), 263 (PPh3ꢁ Hꢂ
Hꢁ, 100%), 209 ([2Mꢁ
2Fe(CO)2PPh3]ꢁ, 65%), 105 ([Mꢁ Fe(CO)2PPh3]ꢁ,
Hꢂ
6%).
/
7.58 (m, 30H), 5.74 (pseudo t, Jꢃ
9.9 Hz, 2H), 5.12ꢀ5.27
4.85 (m, 2H), 2.97
7.3 Hz,
/
(200 MHz): d 7.30ꢀ
/
7.56 (m, 15H), 5.73 (dd, Jꢃ/10.6, 7.9
/
/
Hz, 1H), 5.05 (dd, Jꢃ
/
10.3, 2.1 Hz, 1H), 4.80ꢀ/5.00 (m,
/
2H), 2.84ꢀ
/
2.97 (m, 1H), 2.22ꢀ
/
2.38 (m, 1H), 2.02 (s, 1H),
1.25 (s, 3H); 13C-NMR (75 MHz): d 32.2, 53.0, 69.2,
/
/
70.7, 83.5, 95.6, 128.3, 128.4, 129.1, 129.9, 129.9, 130.9,
/
/
/
133.1, 133.2, 134.6, 135.1, 217.6 [d, J(31Pꢁ
/
13C)ꢃ
/
16 Hz],
14 Hz]; MS (DCI): m/z 497
([MH]ꢁ, 9%), 479 ([MꢂOH]ꢁ, 74%), 423 ([Mꢂ
OHꢂ
2CO]ꢁ, 55%), 263 (PPh3ꢁHꢁ, 100%), 105 ([Mꢂ
OHꢂ
Fe(CO)2PPh3]ꢁ, 100%).
/
/
/
/
/
218.7 [d, J(31Pꢁ
/
13C)ꢃ
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
5.14. trans-Dicarbonyltriphenylphosphine(h4-3-n-
butylcyclohepta-4,6-dienone)iron complex (12d)
5.18. Dicarbonyltriphenylphosphine(h4-8-n-
propylheptafulvene)iron complex (13d) (1:1 mixture of
Z and E isomers)
1
M.p. 139ꢀ
NMR (200 MHz): d 7.30ꢀ
1H), 4.78ꢀ4.93 (m, 1H), 2.67ꢀ
(m, 1H), 1.85ꢀ2.00 (m, 1H), 1.57 (pseudo t, Jꢃ
1H), 1.04ꢀ 6.5 Hz, 3H);
/
140 8C; IR: 1978, 1934, 1634 cmꢂ1; H-
7.56 (m, 15H), 4.93ꢀ5.08 (m,
2.90 (m, 2H), 2.55ꢀ2.69
12.0 Hz,
1
/
/
Oil; IR: 1975, 1915 cmꢂ1; H-NMR (200 MHz): d
/
/
/
7.28ꢀ
3H), 5.02ꢀ
(m, 1H), 3.13ꢀ
2.66 (m, 2H), 1.85ꢀ
1.25ꢀ1.47 (m, 4H), 0.76ꢀ
/
7.58 (m, 30H), 5.52ꢀ
5.18 (m, 2H), 4.74ꢀ
3.26 (m, 1H), 2.90ꢀ
2.02 (m, 2H), 1.62ꢀ
0.95 (m, 6H); 13C-NMR (75
/
5.84 (m, 3H), 5.25ꢀ
4.88 (m, 1H), 4.57ꢀ
3.03 (m, 1H), 2.42ꢀ
1.80 (m, 2H),
/
5.41 (m,
/
/
/
/
/4.70
/
1.39 (m, 6H), 0.85 (pseudo t, Jꢃ
/
/
/
/
13C-NMR (50 MHz): d 14.2, 22.8, 28.8, 41.3, 44.6, 48.8,
56.7, 62.4, 89.4, 92.4, 128.6, 128.7, 130.3, 133.2, 133.4,
134.1, 134.9, 208.9, 215.8 (br), 216.4 (br); MS (DCI): m/
z 539 ([MH]ꢁ, 100%).
/
/
/
/
MHz): d 13.7, 13.9, 22.5, 22.8, 30.2, 30.4, 52.8, 53.8,
57.0, 66.2, 88.2, 88.3, 92.1, 92.5, 117.7, 126.2, 127.4,
128.1, 128.2, 128.3, 129.1, 129.7, 129.7, 129.8, 132.5,
133.1, 133.2, 135.2, 135.2, 135.7, 137.7, 138.7, 216.9 [d,
5.15. cis-Dicarbonyltriphenylphosphine(h4-1-tert-
butylcyclohepta-2,4,6-trienol)iron complex (11f)
J(31Pꢁ
218.7 [d, J(31Pꢁ
10 Hz]; MS (DCI): m/z 521 ([MH]ꢁ, 100%), 465 ([Mꢁ
Hꢂ Hꢂ
2CO]ꢁ, 33%), 147 ([Mꢁ Fe(CO)2PPh3]ꢁ, 26%).
/
13C)ꢃ
/
16 Hz], 217.3 [d, J(31Pꢁ
/
13C)ꢃ
/
17 Hz],
/
13C)ꢃ12 Hz], 218.9 [d, J(31Pꢁ
/
/
13C)ꢃ
/
/
Not isolated pure; IR: 3620, 1975, 1915 cmꢂ1; H-
/
/
/
1
NMR (200 MHz): d 0.82 (s, 9H, tBu), 0.80 (s, 9H, tBu);
MS (DCI): m/z 665 (8%), 579 (6%), 539 ([MH]ꢁ, 100%),
521 ([Mꢂ
435 ([2Mꢂ
([2Mꢂ2OHꢂ
2OHꢂ4COꢂ2PPh3ꢂ
COꢁ
H]ꢁ, 10%), 263 (PPh3ꢁ
OHꢂ
Fe(CO)2PPh3]ꢁ, 19%).
/
OH]ꢁ, 55%), 465 ([Mꢂ
2OHꢂ3COꢂ2PPh3ꢁ
4COꢂ2PPh3ꢁ
H]ꢁ, 2%), 351 ([2Mꢂ
Feꢁ PPh3ꢁ
H]ꢁ, 1%), 305 ([Mꢂ
Hꢁ, 55%), 147 ([Mꢂ
/
OHꢂ
/
2CO]ꢁ, 10%),
6. Supplementary material
/
/
/
/
H]ꢁ, 32%), 407
/
/
/
/
/
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC nos. 179617, 179836, 179893,
179725, 179684, 179989, 180095 for compounds 1, 2c,
/
/
/
/
/
/
/
/
/
/

Y. Coquerel et al. / Journal of Organometallic Chemistry 659 (2002) 176ꢀ
/
185
185
[8] A. Eisenstadt, J.M. Guss, R. Mason, J. Organomet. Chem. 80
(1974) 245.
3f, 4, 7, 9f, 12f. Copies of this information may be
obtained free of charge from The Director, CCDC, 12
[9] B.F.G. Johnson, J. Lewis, P. McArdle, G.L.P. Randall, J. Chem.
Soc. Dalton Trans. (1972) 2076.
Union Road, Cambridge CB2 1EZ, UK (Fax: ꢁ44-
/
1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
[10] A.J. Pearson, K. Srinivasan, J. Chem. Soc. Chem. Commun.
(1991) 392.
[11] M.-C.P. Yeh, C.-C. Hwu, C.-H. Ueng, H.-L. Lue, Organome-
tallics 13 (1994) 1788.
[12] T.-L. Ho, Tetrahedron 41 (1985) 3.
Acknowledgements
[13] Y. Coquerel, J.-P. Depre´s, J. Chem. Soc. Chem. Commun. (2002)
658.
[14] Y. Coquerel, Ph.D. Thesis Dissertation, Universite´ Joseph Four-
ier, Grenoble, France, 2001.
We thank Dr. A. Durif for his help with the structure
determinations. Financial support from the CNRS and
the Universite´ Joseph Fourier (UMR 5616) and a
doctoral fellowship from M.E.N.R.T. to Y.C. are
gratefully acknowledged.
[15] J.A.S. Howell, A.D. Squibb, Z. Goldschmidt, H.E. Gottlieb, A.
Almadhoun, I. Goldberg, Organometallics 9 (1990) 80.
[16] Although the structure of complex 1 has previously been resolved
(see Ref. [4]), the precision obtained at the time does not allow
precise comparison of bond lengths and angles with those of the
structures reported herein.
[17] Molecular Structure Corporation. (1992ꢀ1997). teXsan. Single
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[21] Ref. [15]. Complex 10 was obtained in 91% yield following the
described procedure.
[22] The neat alcohol complexes slowly decomposed on standing in the
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dark at ꢂ30 8C under argon.
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