Synthesis and some chemical properties of 3-ferrocenyl-3-isopropylcyclopropene: 3-ferrocenyl-3-isopropylstructures of cyclopropene and its adducts with 1,3-diphenylisobenzofuran

Article abstract of DOI:10.1016/S0022-328X(99)00721-4

X-ray structural analysis allowed the molecular conformation of 3-ferrocenyl-3-isopropylcyclopropene to be established, where the ferrocenyl fragment occupies a bisecting position relative to the three-membered ring. Some heterolytic cleavage of a σ C-C bond in cyclopropene was observed. As a result, predominantly linear products are formed: 1,1-dimethyl-2-ferrocenyl-1,3-butadiene, 3-ferrocenyl-4-methyl-2-pentene, 3-ferrocenyl-4-methyl-3-pentenine and also 3-isopropyl-1H-cyclopentaferrocene. Cyclopropene forms a classical Diels-Alder adduct with 1,3-diphenylisobenzofuran and an adduct with the intermediate 3-isopropyl-1,2-(1-propene-1,3-diyl)ferrocene. X-ray structural data of exo-1,5-diphenyl-3-anti-ferrocenyl-3-syn-isopropyl-6,7-benzo-8-oxatricyclo[3.2. 1.0^2,4]oct-6-ene are presented.

Full text of DOI:10.1016/S0022-328X(99)00721-4

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 598 (2000) 254–261
Synthesis and some chemical properties of
3-ferrocenyl-3-isopropylcyclopropene:
3-ferrocenyl-3-isopropylstructures of cyclopropene and its adducts
with 1,3-diphenylisobenzofuran
Elena I. Klimova a,*, Marcos Mart´ınez Garc´ıa b, Tatiana Klimova a,
Cecilio Alvarez Toledano b, Ruben Alfredo Toscano b, Lena Ru´ız Ram´ırez a
a Facultad de Qu´ımica, Uni6ersidad Nacional Auto´noma de Me´xico, Cd. Uni6ersitaria, Coyoaca´n, C.P. 04510, Mexico D.F., Mexico
b Instituto de Qu´ımica, Uni6ersidad Nacional Auto´noma de Me´xico, Cd. Uni6ersitaria, Coyoaca´n, C.P. 04510, Mexico D.F., Mexico
Received 9 September 1999; received in revised form 13 November 1999
Abstract
X-ray structural analysis allowed the molecular conformation of 3-ferrocenyl-3-isopropylcyclopropene to be established, where
the ferrocenyl fragment occupies a bisecting position relative to the three-membered ring. Some heterolytic cleavage of a s CꢀC
bond in cyclopropene was observed. As a result, predominantly linear products are formed: 1,1-dimethyl-2-ferrocenyl-1,3-buta-
diene, 3-ferrocenyl-4-methyl-2-pentene, 3-ferrocenyl-4-methyl-3-pentenine and also 3-isopropyl-1H-cyclopentaferrocene. Cyclo-
propene forms a classical Diels–Alder adduct with 1,3-diphenylisobenzofuran and an adduct with the intermediate 3-isopropyl-
1,2-(1-propene-1,3-diyl)ferrocene. X-ray structural data of exo-1,5-diphenyl-3-anti-ferrocenyl-3-syn-isopropyl-6,7-benzo-8-
oxatricyclo[3.2.1.02,4]oct-6-ene are presented. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Cyclopropene; Cyclopropane; Carbenoid intermediate; Carbocation; Rearrangement; Intramolecular transformation; Alkylation;
Deprotonation; Recyclization; Molecular conformation; Diene adduct; Ferrocene
1. Introduction
A quantum-chemical study [1] revealed that the most
probable position of the phenyl fragment in the molecule
of 3-methyl-3-phenylcyclopropene is the nonbisecting
one, relative to the plane of the three-membered ring. The
interaction between the molecular orbitals of the ethylene
and benzene fragments in this conformation determines
the stereoselectivity of the addition reactions [2–6]. These
results are in agreement with our conclusions concerning
the chemical properties of 3-aryl-3-ferrocenylcycloprope-
nes 1a,b [7,8]. The small ring in these compounds is
opened easily on thermal treatment or in the presence of
acids, forming the intermediate carbenoids of type 2 or
the ferrocenylallylic cations of type 3. Then recyclization
in the aryl fragment occurs, without the participation of
the ferrocenyl substituent.
The X-ray structural study of monocrystals of 3-(1-
naphthyl) and of 3-phenyl-3-ferrocenylcyclopropenes
(1a and 1b) [7,8] revealed that the aryl substituents have
a non-bisecting orientation, which determines the regio-
selectivity of the recyclization reaction.
* Corresponding author. Fax: +525-622-5366.
E-mail address: klimova@servidor.unam.mx (E.I. Klimova)
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00721-4

E.I. Klimo6a et al. / Journal of Organometallic Chemistry 598 (2000) 254–261
255
The spatial structure of the earlier synthesized 3-
alkyl-3-ferrocenylcyclopropenes (1c–e) [9,10] has not
been established up to now. The separation of the
Diels–Alder adducts 4c–e, which are derivatives of the
intermediate 3-alkyl-1H-cyclopentaferrocenes (5c–e),
suggested that the ferrocene fragment in compounds
1c–e might occupy a non-bisecting position in analogy
to the position of the aryl fragments in 1a and 1b.
Besides, we found that even for an equimolar mixture
of the reagents, it is difficult to avoid the formation of
small amounts of completely reduced 1-ferrocenyl-1-
isopropylcyclopropane (9):
2-Bromo-1-ferrocenyl-1-isopropylcyclopropane (10)
was separated as a mixture of Z and E isomers with
ratio 3:1 (yield approximately 62%). The assigment of
the isomer monobromides to Z and E geometry was
1
carried out by H-NMR spectroscopy (Table 1) taking
into account the earlier established [7–10,14] NMR
criteria for distinguishing Z- and E-geometric isomers
of monobromoferrocenylcyclopropanes.
Cyclopropene (1f) was synthesized by dehydrobro-
mation of the monobromide (Z-/E-10) in the presence
t
of 5% excess of BuOK in DMSO:
However, this assumption was debatable because the
reaction of intramolecular transformations in com-
pounds 1c–e, contrary to that in the cyclopropenes 1a
and 1b, resulted in the formation of a large amount of
linear and polymeric products, together with the ex-
pected products of alkylation of the ferrocene
substituent.
2. Results and discussion
In a continuation of our previous studies, we synthe-
sized the crystal 3-ferrocenyl-3-isopropylcyclopropene
(1f) from 2,2-dibromo-1-ferrocenyl-1-isopropylcyclo-
propane (6). The dibromide 6 was prepared according
to the following reaction scheme [11–13]:
We separated compounds 11 and 12 as reaction side
products, which are obviously related to opening of the
three-membered ring in monobromocyclopropane 10 in
t
the presence of BuOK in DMSO. One of the possible
reaction paths is via solvolysis of the monobromide 10,
resulting in the intermediate alkylferrocenylallyl cation
13 followed by further transformations (deprotonation
and intramolecular alkylation) to form products 11 and
12:
Compounds 6, 7 and 8 are synthesized easily with a
yield of about 70–75%.
Cyclopropene (1f) is easily crystallized in n-heptane
forming orange crystals with m.p. 62–63°C. Freshly
prepared crystals of 1f were studied by X-ray analysis.
Fig. 1 shows a general view of the 1f molecule and Fig.
2 shows one of its projections.
Further we established that the dibromide 6 is easily
reduced in a mixture of EtMgBr and Ti(OiPr)4 [14].
The basic element in the structure of 1f is the three-
membered ring. It is an acute-angled isosceles triangle
distorted in the direction of atom C(13). The length of
,
the C(11)ꢁC(12) double bond is l=1.27 A and the
acute angle at C(13) has a value of ꢀ =50.0°. The
position of the ferrocenyl fragment in 1f corresponds to

256
E.I. Klimo6a et al. / Journal of Organometallic Chemistry 598 (2000) 254–261
a bisecting orientation relative to the small ring (Fig. 2).
The bond lengths FeꢀC and CꢀC in the ferrocenyl
fragment, as well as the geometry of the ferrocenyl
sandwich, are the usual ones. Therefore, it appears that
the molecules of 3-aryl-3-ferrocenylcyclopropenes (1a,b)
and of 3-alkyl-3-ferrocenylcyclopropenes (1c–f) have a
similar conformation with a bisecting orientation of the
ferrocenyl substituent and a non-bisecting position of
the aryl and alkyl groups.
formed intermediate carbenoid compound 14 is then
isomerized to give the diene 11, compound 12 (ratio
10:1) and polymeric products:
Further we established that the chemical properties
of 3-ferrocenyl-3-isopropylcyclopropene correspond to
its conformational structure. For example, cyclopropene
1f is unstable both in solution and in its crystal state. It
gradually isomerizes in cold solutions (0°C) of hexane,
benzene or chloroform to form 1,1-dimethyl-2-ferro-
cenyl-1,3-butadiene (11) (yield 42%), 3-isopropyl-1H-cy-
clopentaferrocene (12) (yield 4%) and polymeric
products of unknown structure and composition. These
results are obviously related to the easy opening of the
cyclopropene ring even at low temperatures. The
The crystals of the cyclopropene 1f are gradually con-
verted into an orange oil on prolonged storage (0°C, 1–2
months). The chromatographic analysis of the oil indi-
cated the presence of compounds 11, 12 and of polymers.
We managed to trap the carbenoid intermediate 14,
formed initially at the heterolytic cleavage of the CꢀC
bond in the three-membered ring using diphenyl-
acetylene. 5-Ferrocenyl-5-isopropyl-1,2-diphenylcyclo-
pentadiene (15) was formed (yield 54%) according to
the following scheme:
Table 1
1H-NMR spectroscopy data for the obtained compounds (300 MHz, CDCl3, TMS) a
Compounds C5H5
C5H4
CH2
CH
CH3, Ar
1f
6
4.12 s, 5H
4.02 s, 4H
2.41 m, 1H, J=6.76; 6.95 0.79 d, 6H, J=6.76
s, 2H
4.16 s, 5H
4.21 m, 2H, 4.25 m, 2H
1.75 d, 1H, J=7.2; 2.11
d, 1H, J=7.2
2.17 m, 1H, J=6.8
0.98 d, 3H, J=6.8; 1.15
d, 3H, J=6.8
7
8
4.15 s, 5H
4.06 s, 5H
4.45 m, 2H, 4.75 m, 2H
4.19 m, 2H, 4.38 m, 2H
3.07 m, 1H, J=6.88
2.64 m, 1H, J=6.88, 1.06 1.18 d, 6H, J=6.88
1.17 d, 6H, J=6.88
4.90 bs, 1H, 5.21 d, 1H,
J=1.06
9
4.10 s, 5H
4.14 s, 5H
4.12 m, 2H, 4.14 m, 2H
4.07 m, 1H, 4.12 m, 2H,
4.18 m, 1H
0.66 m, 2H, 0.75 m, 2H
1.45 dd, 1H, 2.05 dd, 1H, 1.93 m, 1H, J=6.0; 3.47
2.80 m, 1H, J=6.7
0.93 d, 6H, J=6.7
0.83 d, 3H, J=6.0; 0.91
d, 3H, J=6.0
Z-10
J
J
gem=6.50, Jtrans=5.20,
cis=8.10
dd, 1H, J=5.20, 8.10
E-10
4.10 s, 5H
4.13 s, 5H
3.98 m, 2H, 4.05 m, 2H
3.90 m, 2H, 4.22 m, 2H
1.64 dd, 1H, 1.89 dd, 1H, 1.72 m, 1H, J=6.9; 3.67
0.80 d, 3H, J=6.9; 0.85
d, 3H, J=6.9
J
J
gem=5.12, Jtrans=6.10,
cis=7.6
dd, 1H, J=6.10, 7.6
11
5.05 dd, 1H, J=0.7, 17.5; 6.01 dd, 1H, J=10.6,
5.14 dd, 1H, J=0.7, 10.6 17.5
1.75 s, 3H, 1.79 s, 3H,
12
15
4.12 s, 5H
4.09 s, 5H
4.20 m, 1H, 4.31 m, 2H
3.62 m, 1H, 4.01 m, 1H,
4.12 m, 1H, 4.14 m, 1H
4.28 d, 2H, J=6.69
2.94 m, 1H, J=7.15
2.23 m, 1H, J=6.6; 6.70
d, 1H, 6.78 d, 1H, J=
5.61
1.20 d, 6H, J=7.15
0.85 d, 3H, 1.30 d, 3H,
J=6.6; 6.90 m, 2H, 7.16
m, 8H
16a
16b
4.07 s, 5H
3.98 s, 5H
3.91 s, 4H
2.45 s, 2H, 2.95 m, 1H,
J=6.66
0.39 d, 6H, J=6.66;
6.95–7.12 m, 4H, 7.40–
7.60 m, 6H, 7.75–7.83 m,
4H
0.42 d, 6H, J=6.7; 7.05
m, 7.15 m, 7.46 m, 7.70
m, 7.81 m, 14H
4.10 s, 4H
2.40 s, 2H, 2.72 m, 1H,
J=6.7
17
18a
4.12 s, 5H
4.05 s, 5H
4.15 m, 2H, 4.19 m, 2H
4.00 m, 1H, 4.20 m, 2H,
4.27 m, 1H
2.98 s, 1H
2.40 m, 1H, J=6.8: 5.51
q, 1H, J=6.6
1.85 s, 3H, 2.02 s, 3H
1.17 d, 6H, J=6.8; 1.81
d, 3H, J=6.6
18b
19
4.03 s, 5H
4.00 s, 5H
3.75 m, 1H, 4.01 m, 1H,
4.18 m, 1H, 4.43 m, 1H
3.71 d, 1H, 3.90 d, 1H,
J=2.10
2.75 m, 1H, J=6.78; 5.83 1.19 d, 6H, J=6.78; 1.70
q, 1H, J=6.62
d, 3H, J=6.62
2.15 dd, 1H, J=15.0, 2.8; 2.63 m, 1H; 4.12 td, 1H,
2.90 dd, 1H, J=15.0, 8.9 J=8.9, 2.8; 4.35 d, 1H,
J=8.9
0.89 d, 6H, J=6.2; 6.70–
6.90 m, 7.30–7.70 m, 14H
a l (ppm), J (Hz).

E.I. Klimo6a et al. / Journal of Organometallic Chemistry 598 (2000) 254–261
257
Freshly prepared cyclopropene 1f interacts with 1,3-
diphenylisobenzofuran at boiling in benzene forming a
Diels–Alder adduct 16 and compounds 17, 18a,b and
19:
,
Fig. 1. Crystal structure of 1f. Selected bond lengths (A): C11ꢀC12
=
1.274(6); C11ꢀC13=1.510(5); C12ꢀC13=1.507(6); C13ꢀC14=1.542(6);
C1ꢀC13=1.487(5). Selected bond angles (°): C11ꢀC13ꢀC12=50.0(3);
C11ꢀC12ꢀC13=65.1(3); C12ꢀC11ꢀC13=64.9(3).
The classical Diels–Alder adduct was formed as a
mixture of two structural isomers 16a and 16b (3:1) as
revealed by 1H-NMR (Table 1). The isomers were
separated by TLC on SiO2. The monocrystals of isomer
16a (formed with a higher yield from a solution of
n-heptane) were studied by X-ray structural analysis
(Fig. 3). The X-ray results indicate that the three-mem-
bered ring is practically an equilateral triangle. The
three-membered ring is condensed with the six-mem-
bered ring in a rigid boat conformation. The adduct
16a has an exo structure. The isopropyl group has a syn
position relative to the bridge oxygen atom and a
non-bisecting position relative to the small ring. The
ferrocenyl fragment occupies the anti position relative
to the oxygen atom. Contrary to the adduct 16a, an
exo-1,5-diphenyl-3-syn-ferrocenyl-3-anti-isopropyl-6,7-
benzo-8-oxatricyclo[3.2.1.02,4]oct-6-ene structure is as-
signed to isomer 16b.
result in the formation of the intermediate 3-isopropyl-
1,2-(1-propene-1,3-diyl)ferrocene (20). Then it is trans-
formed into the adduct 19. These transformations are
well described for a-ferrocenylcarbocations having
bulky substituents [10,15–17]. They include migration
of the isopropyl substituent from the a-ferrocenylcarbo-
cationic center of 14a to position 3 of the C5H4 group
of ferrocene. Also, the intramolecular alkylation in
position 2 of the cyclopentadiene ring of ferrocene is
well known for a-ferrocenylcarbocations [18] and car-
benoids [19]:
Without doubt, the formation of compounds 17,
Z-18a and of E-18b (according to 1H-NMR data,
Table 1), as well as 19, is possible only if small ring
opening takes place during the reaction and the further
transformations of the intermediates 14a,b. For exam-
ple, the intermolecular disproportionation of 14a,b
leads to the formation of 17 and of 18a,b. In our
opinion the intramolecular transformations in 14a,b

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E.I. Klimo6a et al. / Journal of Organometallic Chemistry 598 (2000) 254–261
molecular orbitals of the ethylene fragment of the small
ring cannot interact with the orbitals from the cy-
clopentadiene ring of ferrocene. It is the absence of this
interaction that results in the predominant formation of
linear products of the intramolecular transformations
of 3-alkyl-3-ferrocenylcyclopropenes.
Besides, we would like to point out, that a small
amount of products of intramolecular alkylation of
ferrocene were obtained.
3. Experimental
1
The H- and 13C-NMR spectra were recorded on a
Unity Inova Varian spectrometer (300 y 75 MHz) in
CDCl3 solutions using Me4C as an internal standard
(see Tables 1 and 2). Table 3 contains the elemental
analysis results. The chromatographic separation was
carried out on an Al2O3 (Brockmann activity III)
packed column. The X-ray patterns were recorded on a
Siemens P3/PC diffractometer (compound 16a) and for
compound 1f, on a Siemens P4/PC. The crystallo-
graphic data, the experimental conditions and correc-
tions are given in Table 4. The chemical reactions were
carried out in dry argon atmosphere and absolute grade
solvents.
3.1. Isopropylferrocenylketone (7)
Fig. 2. One of the projections of molecule 1f.
Isopropylferrocenylketone (7) was prepared by
Friedel–Crafts acylation of ferrocene with (CH3)2CH-
COCl in the presence of AlCl3 in CH2Cl2. The ketone 7
had a yield of 76%, orange oil [11].
1
Comparing the H-NMR data of compound 19 with
the spectra of similar adducts (see Ref. [10]), we as-
signed the endo-1,7-diphenyl-3,4-(3-isopropylferro-
ceno)-8,9-benzo-10-oxatricyclo[5.2.1.02,4]deca-3,8-diene
structure to 19.
3.2. 1-Ferrocenyl-1-isopropylethylene (8)
In such a way, the X-ray results on monocrystals of
one of the members of the 3-alkyl-3-ferrocenylcyclo-
propene family revealed that the ferrocenyl fragment in
these compounds occupies a bisecting position relative
to the three-membered ring, similar to that in 3-aryl-3-
ferrocenyl-cyclopropenes. In this conformation the
1-Ferrocenyl-1-isopropylethylene (8) was prepared by
the Wittig reaction [12] from ketone 7 and methylene-
triphenylphosphorane. The alkene 8 had 73% yield
(after Al2O3 chromatography using hexane as eluent),
orange crystals, m.p. 84–85°C.
Table 2
13C-NMR spectroscopy data for compounds 1f, 7, 10b and 16a (75 MHz, CDCl3, TMS) a
Assignment
1f
7
10b
16a
68.6
65.3, 67.2
96.4
12.1, 13.1
18.3, 41.4
38.7, 88.7
C5H5
C5H4
CipsoFc
CH3
CH
C
CHꢁ
Ar
68.01
69.5
69.4, 72.1
78.1
19.4
37.2
68.3
66.9
98.7
20.7
29.9
34.9
110.6
66.7, 66.8, 69.1, 69.5
90.9
19.1, 19.8
23.9, 34.2
28.9
208.5
119.1, 125.8, 127.8, 128.1, 128.4
136.8, 151.5
Cipso
CH2
31.1
a l (ppm).

E.I. Klimo6a et al. / Journal of Organometallic Chemistry 598 (2000) 254–261
259
,
Fig. 3. Crystal structure of 16a. Selected bond lengths (A): C8ꢀC9=1.510(8); C9ꢀC10=1.516(8); C8ꢀC10=1.512(7); C10ꢀC33=1.541(9);
C10ꢀC23=1.506(8); C7aꢀC3a=1.396(8). Selected bond angles (°): C8ꢀC10ꢀC9=59.8(3); C8ꢀC9ꢀC10=60.0(4); C9ꢀC8ꢀC10=60.2(4); C1ꢀC8ꢀC9=
102.5(5); C8ꢀC9ꢀC3=102.9(4).
3.3. 2,2-Dibromo-1-ferrocenyl-1-isopropylcyclo-
propane (6)
procedure [13], with a yield of 74%, orange crystals,
m.p. 123–124°C.
3.4. Reduction of the dibromide 6 [14]
2,2-Dibromo-1-ferrocenyl-1-isopropylcyclopropane
(6) was prepared from alkene 8 following a known
A few drops of tetraisopropyltitanate and a solution
Table 3
Elemental analysis data for the obtained compounds
Compound
Found (%)
C
Molecular formula
Calculated (%)
H
Fe
Br
C
H
Fe
Br
1f
6
7
8
72.29
44.85
65.52
70.99
71.72
55.48
72.28
72.14
81.21
80.42
72.87
71.52
80.72
7.03
4.34
6.43
7.05
7.47
5.39
6.71
6.99
6.22
5.93
6.03
7.65
5.85
21.08
13.70
21.74
22.08
20.70
16.21
20.73
21.03
12.69
10.54
21.19
20.98
10.61
C16H18Fe
72.21
45.09
65.65
70.91
71.66
55.35
72.21
72.21
81.08
80.60
72.75
71.66
80.60
6.81
4.26
6.30
7.14
7.51
5.52
6.81
6.81
6.35
6.01
6.11
7.51
6.01
20.98
13.10
21.80
21.95
20.83
16.09
20.98
20.98
12.57
10.41
21.14
20.83
10.41
37.63
C16H18Br2Fe
C14H16FeO
C15H18Fe
C16H20Fe
C16H19 BrFe
37.55
9
Z-, E-10
11
12
15
16a,b
17
23.19
23.04
C16H18Fe
C16H18Fe
C30H28Fe
C36H32FeO
C16H16Fe
C16H20Fe
18a,b
19
C
36H32FeO

260
E.I. Klimo6a et al. / Journal of Organometallic Chemistry 598 (2000) 254–261
Table 4
3.5. 3-Ferrocenyl-3-isopropylcyclopropene (1f)
Crystal data, data collection and refinement parameters for 1f and
16a
Monobromide 10 (1.05 g, 3 mmol) was added with
intensive stirring to a solution of 0.35 g (3.15 mmol) of
tBuOK in 30 ml of absolute DMSO. The mixture was
stirred at 20°C for 6 h, then 50 ml of benzene and 50 ml
of water were added. The organic layer was separated
and washed with water. The solvent was removed by
heating in vacuum and the remaining oil was separated
by thin-layer chromatography on silica gel (n-hexane).
Orange crystals of cyclopropene 1f, Rf=0.56, m.p.
62–63°C, were obtained with a yield of 61% (0.49 g).
Also, 0.035 g (5%) of yellow powder of compound 12,
Rf=0.67, m.p. 71–72°C and 0.09 g (11%) of 1,1-
Data
1f
16a
Molecular formula
C16H18Fe
C
36H32FeO·
0.5C7H16
586.6
293
Monoclinic
P21/c
11.199(2)
15.521(2)
18.646(2)
90
102.97(2)
90
3158.3(7)
4
Formula weight (g mol−1
Temperature (K)
Crystal system
Space group
a (A)
b (A)
c (A)
h (°)
i (°)
k (°)
)
266.15
293
Monoclinic
P21/c
13.622(2)
12.068(2)
8.330(1)
90.0
102.42(1)
90.0
,
,
,
dimethyl-2-ferrocenyl-1,3-butadiene
11,
Rf=0.48,
orange oil, were obtained. The latter compound is
unstable and rapidly decomposes at storage.
3
,
V (A )
1337.3(3)
4
1.322
Z
Dcalc. (Mg m−3
)
1.234
3.6. Intramolecular isomerization of cyclopropene (1f)
Absorption coefficient
(mm−1
F(000)
1.102
0.507
)
560
1244.08
A solution of 0.27 g (1 mmol) of cyclopropene 1f in
50 ml of solvent (n-hexane, benzene, chloroform) was
kept at 0°C for 3 days. Then the solvent was removed
in vacuum and thin-layer chromatography on silica gel
(n-hexane) was carried out. The following compounds
were separated: 0.33 g (42%) of compound 11, Rf=
0.48; 0.08 g (10%) of the initial cyclopropene 1f, Rf=
0.55, m.p. 62–63°C; 0.04 g (4%) of compound 12,
Rf=0.68, m.p. 72°C.
,
Radiation, u (A)
Monochromator
[ range (°)
Mo–Ka, 0.71073 Mo–Ka, 0.71073
Graphite
1.50–25.00
2450
2349
Graphite
1.50–30.0
9627
9199
0.0293
R1=0.0725,
b wR2=0.0871
R1=0.1627,
b wR2=0.1050
Reflections collected
Reflections independent
Rint
0.0347
Final R indices [I\2|(I)]
R1=0.0422,
a wR2=0.1035
R1=0.0652,
a wR2=0.1269
2349/0/155
1736(I\2|(I))
Full-matrix least- Full-matrix least-
squares on F2
1.105
R indices (all data)
Data/restraints/parameters
Reflections observed
Refinement method
3.7. Interaction of cyclopropene 1f with
diphenylacetylene
3578(F\4.0|(F))
squares on F2
1.65
−0.38/0.56
Goodness-of-fit
Minimum/maximum
A solution of 0.27 g (1 mmol) of cyclopropene 1f and
0.27 g (1.5 mmol) of diphenylacetylene in 50 ml of
benzene was boiled for 3 h till the disappearance of the
spot of the initial cyclopropene 1f on silica gel (n-hex-
ane). After the removal of the solvent and thin-layer
chromatography on silica gel (n-hexane–benzene, 2:1),
we obtained 0.24 g (54%) of compound 15, Rf=0.38,
as orange powder, m.p. 186–187°C.
−0.414/0.395
residual electron density
−3
,
(e A
)
Hydrogen atoms
Riding
Riding
a Weighting scheme: w=|2(Fo2)+(0.0735P)2 where P=(Fo2+2F2c)/3.
b Weighting scheme: w−1=|2(F)+0.0008F2.
3.8. Reaction of cyclopropene 1f with
1,3-diphenylisobenzofuran
(3.3 mmol) of EtMgBr in ether were added at intensive
stirring to a solution of 1.28 g (3 mmol) of dibromocy-
clopropane (6) in 50 ml of ether. The mixture
was stirred at 20°C till its colour changed from dark
brown to yellow and then the reaction mixture was
decomposed by the addition of 50 ml of water. The
organic layer was separated and the solvent was evapo-
rated at room temperature in vacuum and then thin-
layer chromatography on silica gel (n-hexane) was
carried out. The yield of monobromides Z-, E-10 (3:1),
Rf=0.49, as orange oil was 0.65 g (62%). Also, 0.1 g
(12%) of cyclopropane 9, Rf=0.65, orange oil, was
obtained.
A solution of 0.4 g (1.5 mmol) of cyclopropene 1f
and of 0.56 g (2 mmol) of 1,3-diphenylisobenzofuran in
60 ml of benzene was boiled for 5 h (control performed
by thin-layer chromatography on silica gel, as in the
previous experiment). The solvent was then removed
and thin-layer chromatography on silica gel (n-hexane–
benzene, 3:1) was carried out. The following com-
pounds were separated: 0.06 g (13%) of 3-ferrocenyl-
4-methyl-2-pentene (18a,b) (a mixture of Z and E
isomers, 3:1), Rf=0.75, orange oil; 0.042 g (10%)
of 3-ferrocenyl-4-methyl-3-penteneine (17) Rf=0.54,

E.I. Klimo6a et al. / Journal of Organometallic Chemistry 598 (2000) 254–261
261
orange oil (rapidly decomposing at storage); 0.08 g
References
(9.8%) of the adduct 19, Rf=0.42, yellow crystals, m.p.
212–213°C; 0.40 g (49%) of the adduct 16a,b (3:1),
Rf=0.34, yellow crystals, m.p. 198–199°C. Isomer 16a
was separated from the mixture of isomers by thin-layer
chromatography on silica gel (n-hexane–benzene, 1:1).
The following compounds were separated: 0.15 g of
isomer 16a, Rf=0.64, yellow crystals, m.p. 203–204°C
(formed from a solution of n-heptane), and 0.16 g of
the mixture of adducts 16a and 16b (1:1), Rf=0.70,
m.p. 194–198°C.
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4. Supplementary material
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 133 900 for 3-ferrocenyl-3-iso-
propylcyclopropene (1f) and no. 133 901 for exo-1,5-
diphenyl-3-anti-ferrocenyl-3-syn-isopropyl-6,7-benzo-8-
oxatricyclo[3.2.1.02,4]oct-6-ene (16a). Copies of this in-
formation may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (Fax: +44-1223-336033; e-mail: de-
posit@ccdc.cam.ac.uk or www: http://www.ccdc.
cam.ac.uk).
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Financial support from CONACyT (Mexico) is
gratefully acknowledged. We would like to thank Oscar
1
Salvador Yan˜ez Mun˜oz for H- and 13C-NMR spectra.
.