Fragmentation and 1,2-addition reactions upon action of methyllithium on coupling products of ferrocenecarbaldehyde with dibenzoylmethane

Article abstract of DOI:10.1080/00397910802138660

2-Ferrocenylmethylidene-1,2-diphenylpropanedione (3), 2,4-dibenzoyl-3- ferrocenyl-1,5-diphenylpentane-1,5-dione (4), and 2,4-dibenzoyl-3-ferrocenyl-2- [(ferrocenyl)hydroxymethyl]-1,5-diphenylpentane-1,5-dione (5) react with MeLi to undergo fragmentation a

Full text of DOI:10.1080/00397910802138660

Synthetic Communications1, 38: 2299–2315, 2008
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910802138660
Fragmentation and 1,2-Addition Reactions upon
Action of Methyllithium on Coupling Products
of Ferrocenecarbaldehyde with Dibenzoylmethane
1
E. I. Klimova, T. Klimova Berestneva, J. M. Martınez Mendoza,
1
1
´
1
2
2
´
´
´
J. M. Mendez Stivalet, R. A. Toscano, and M. Martınez Garcıa
1Faculty of Chemistry, National Autonomous University of Mexico,
University City, Coyoacan, Mexico City, Mexico
2Institute of Chemistry, National Autonomous Unviersity of Mexico, University
City, Coyoacan, Mexico City, Mexico
Abstract: 2-Ferrocenylmethylidene-1,2-diphenylpropanedione (3), 2,4-dibenzoyl-
3-ferrocenyl-1,5-diphenylpentane-1,5-dione (4), and 2,4-dibenzoyl-3-ferrocenyl-2-
[(ferrocenyl)hydroxymethyl]-1,5-diphenylpentane-1,5-dione (5) react with MeLi
to undergo fragmentation and 1,2-addition or only 1,2-addition at the carbonyl
group. Dehydration of intermediate tertiary alcohols affords a-methylstyrene (6),
3-ferrocenyl-1-phenylprop-2-enone (7), 3,5-diferrocenyl-1-phenyl-4-(1-phenylvi-
nyl)cyclohexene (8), 3-ferrocenylmethylidene-2,4-diphenylpenta-1,4-diene (9),
2-benzoyl-1-ferrocenyl-3-phenylbuta-1,3-diene (10), 2-benzoyl-1-ferrocenyl-3-
methylindene (11), 4-ferrocenyl-2-methyl-2,6-diphenyl-3,4-dihydro-2H-pyran (19),
and (Z,Z)-2,4-dibenzoyl-1,3-diferrocenyl-5-phenylhexa-1,4-diene (21), isolated by
chromatography. The spatial structures of ferrocenyldihydropyran (19) and difer-
rocenylhexadiene (21) were established by X-ray diffraction analysis.
Keywords: 1,2-Addition; (Z,Z)-2,4-dibenzoyl-1,3-diferrocenyl-5-phenylhexa-1,
4-diene; 4-ferrocenyl-2-methyl-2,6-diphenyl-3,4-dihydro-2H-pyran; 2-ferrocenyl-
methylidene-1,2-diphenylpropanedione; Fragmentation
Received in the USA March 23, 2008
Address correspondence to E. I. Klimova, Facultad de Quımica, Universidad
´
Nacional Autonoma de Mexico, Cd. Universitaria, Coyoacan, C.P. 04510,
ꢀ
Mexico D.F., Mexico. E-mail: klimova@servidor.unam.mx
ꢀ
´
´
´
2299

2300
E. I. Klimova et al.
INTRODUCTION
Cross-conjugated trienes with a linear backbone containing ferro-
cenyl substituents in the molecule are virtually unexplored. In our
communications,[1,2] we reported the synthesis of cross-conjugated
Z- and E-2-acetyl-1-ferrocenyl-3-methylbuta-1,3-dienes (1a,b) and 3-
ferrocenylmethylidene-2,4-dimethylpenta-1,4-diene (2) by the reaction
of methyllithium with 3-ferrocenylmethylidenepentane-2,4-dione, fol-
lowed by dehydration of the resulting tertiary alcohols (Scheme 1).
Polyene compounds of the ferrocene series with terminal methylene
groups[3,4] have gained recently prominence by virtue of their exciting
structure, chemical reactivity, and potential use as molecular building
blocks[5] and in the realm of supramolecular chemistry[6,7] as redox
switching receptors.[8]
Ferrocenyl-substituted trienes of the types 1 and 2 described by us
previously[1,2] are highly reactive compounds. We studied their protona-
tion, cycloaddition, proton- and cation-catalyzed dimerization, and
cyclodimerization.
Studies on the possibilities of an access to the linear cross-conjugated
polyenes with lateral ferrocenyl and aryl substituents and investigations
into their chemical and electrochemical properties is an important task
for synthetic and theoretical organic chemistry and polymer chemistry.
With the aim of synthesizing aryl(ferrocenyl)-substituted cross-
conjugated trienes and polyenes, we have carried out coupling of ferroce-
necarbaldehyde with dibenzoylmethane and investigated the reactions of
the resulting products with methyllithium.
Scheme 1. Synthesis of Z- and E-2-acetyl-1-ferrocenyl-3-methylbuta-1,3-dienes
(1a,b) and 3-ferrocenylmethylidene-2,4-dimethylpenta-1,4-diene (2).

Fragmentation of 2,4-Dibenzoylferrocenyl-1,5-diones
2301
Scheme 2. Reaction of ferrocenecarbaldehyde with dibenzoylmethane.
RESULTS AND DISCUSSION
The reaction of ferrocenecarbaldehyde with dibenzoylmethane afforded
three coupling products: 2-ferrocenylmethylidene-1,3-diphenylpropane-
1,3-dione (3, ꢀ42%), 2,4-dibenzoyl-3-ferrocenyl-1,5-diphenylpentane-
1,5-dione (4, ꢀ20%), and 2,4-dibenzoyl-3-ferrocenyl-2-[ferrocenyl)hy-
droxymethyl]-1,5-diphenylpentane-1,5-dione (5, ꢀ13%) (Scheme 2).
These coupling products were isolated by column chromatography
on alumina (Brockmann activity III, see Experimental section). Their
structures were established based on the data from mass spectrometry,
1
IR, and H and 13C NMR spectroscopy. According to the data from
1H NMR spectroscopy, hydroxytetraone (5) represented a mixture of
two diastereomers (5a and 5b) in a ratio of ꢀ1:1, which could not be
separated by chromatography.
2,4-Dibenzoyl-3-ferrocenyl-1,5-diphenylpentane-1,5-dione (4) was
also synthesized by the Michael coupling of 2-ferrocenylmethylidene-
1,3-diphenylpropane-1,3-dione (3) with dibenzoylmethane, and
2,4-dibenzoyl-3-ferrocenyl-2-[(ferrocenyl)hydroxymethyl]-1,5-diphenylpen-
tane-1,5-dione (5) was obtained by aldol condensation of compound 4
with ferrocenecarbaldehyde (Scheme 3).
Compound 3 was intended to be employed for the synthesis of cross-
conjugated ferrocenyl(diphenyl)triene, while compounds 4 and 5 were
intended for the synthesis of polyenes. To this end, the reactions of these
compounds with methyllithium have been investigated.
Scheme 3. Preparation of 2,4-dibenzoyl-3-ferrocenyl-1,5-diphenylpentane-1,5-
dione and 2,4-dibenzoyl-3-ferrocenyl-2-[(ferrocenyl)hydroxymethyl]-1,5-diphe-
nylpentane-1,5-dione.

2302
E. I. Klimova et al.
Scheme 4. Reaction of 2-ferrocenylmethylidene-1,3-diphenylpropane-1,3-dione
with methyllithium.
2-Ferrocenylmethylidene-1,3-diphenylpropane-1,3-dione (3) was
made to react with excess of methyllithium; the reaction mixture was
quenched with water and concentrated, and the residue was treated with
glacial acetic acid to give compounds (6–11) isolated by column chroma-
tography on alumina (Scheme 4).
Obviously, compounds 6, 7, and 8 result from fragmentation (a) and
1,2-addition (b) reactions that occur under the action of methyllithium
on ferrocenylmethylidene(dibenzoyl)methane 3 (Scheme 5).
3,5-Diferrocenyl-1-phenyl-4-(1-phenylvinyl)cyclohexene (8) repre-
sents a cyclodimer of 1-ferrocenyl-phenylbuta-1,3-diene (15); this is
formed upon cationic cycloaddition of allylic cation 14 to diene 15
(Scheme 5). The mechanism of cationic cycloaddition to ferrocenyl-
buta-1,3-dienes and the effect of stereoelectronic factors have been stud-
ied in detail earlier.[9] It is noteworthy that cyclodimer 8 is formed as a
single diastereomeric (1H NMR data) despite the presence of three stereo-
genic centers. The physicochemical characteristics of compound 8 and 1H
NMR spectroscopic data totally coincide with those reported earlier.[9]
Compounds 9 and 10 resulted from the classical 1,2-addition of
methyllithium to the carbonyl group followed by dehydration of tertiary
alcohols 16 and 17 in an acidic medium (Scheme 6).
2-Benzoyl-1-ferrocenyl-3-methylindene (11) is the intramolecular
alkylation product of the phenyl ring in the intermediate 2-benzoyl-1-
ferrocenyl-3-methyl-3-phenylallyl cation (18) (Scheme 6). To confirm
the proposed reaction pathways (Schemes 5 and 6), we performed chro-
matographic separation of reaction products of compound 3 with
methyllithium following aqueous workup. The following products were
isolated: 2-phenylpropan-2-ol (13), chalcone (7), 4-ferrocenyl-2-phenyl-
but-3-en-2-ol (12), diol (16), and hydroxyketone (17). The latter was

Fragmentation of 2,4-Dibenzoylferrocenyl-1,5-diones
2303
Scheme 5. Plausible mechanism for the formation of compounds 6–8 from
the reaction of 2-ferrocenylmethylidene-1,3-diphenylpropane-1,3-dione 3 with
methyllithium.
Scheme 6. Mechanism for the formation of compounds 9–11 from the reaction of
2-ferrocenyl-methylidene-1,3-diphenylpropane-1,3-dione 3 with methyllithium.

2304
E. I. Klimova et al.
Scheme 7. Plausible mechanism for the formation of compound 19 from the reac-
tion of 2,4-dibenzoyl-3-ferrocenyl-1,5-diphenylpentane-1,5-dione 4 with methyl-
lithium.
isolated as a nonseparable mixture of two diastereomeric forms in a ratio
of 2:1; their configurations could not be determined.
We also found that 2,4-dibenzoyl-3-ferrocenyl-1,5-diphenylpentane-
1,5-dione (4) reacts with an excess of methyllithium to afford a-methyl-
styrene (6) and 4-ferrocenyl-2-methyl-2,6-diphenyl-3,4-dihydro-2H-pyran
(19). Scheme 7 depicts a tentative reaction pathway.
Figure 1. Structure of 19 as determined by X-ray crystallography.

Fragmentation of 2,4-Dibenzoylferrocenyl-1,5-diones
2305
Table 1. Selected bond lengths and bond angles for 19 and 21
Angles, x (ꢁ)–
˚
Length r (A)
Bond
Bond
19
O(1)ꢂC(2)
C(2)ꢂC(3)
C(3)ꢂC(4)
C(4)ꢂC(5)
C(5)ꢂC(6)
O(1)ꢂC(6)
C(6)ꢂC(14)
C(2)ꢂC(8)
C(2)ꢂC(7)
C(4)ꢂC(20)
1.449(3)
1.538(3)
1.498(3)
1.509(3)
1.321(3)
1.375(3)
1.481(3)
1.521(3)
1.510(3)
1.520(3)
21
C(2)ꢂO(1)ꢂC(6)
C(3)ꢂC(2)ꢂO(1)
C(2)ꢂC(3)ꢂC(4)
C(3)ꢂC(4)ꢂC(5)
C(4)ꢂC(5)ꢂC(6)
C(5)ꢂC(6)ꢂO(1)
C(5)ꢂC(6)ꢂC(14)
C(7)ꢂC(2)ꢂC(8)
C(3)ꢂC(4)ꢂC(20)
C(3)ꢂC(2)ꢂC(7)
117.29(19)
108.1(2)
112.1(2)
108.2(2)
124.2(2)
122.6(2)
125.4(2)
111.1(2)
114.0(2)
110.6(2)
C(1)ꢂO(1)
C(1)ꢂC(2)
C(2)ꢂC(3)
C(3)ꢂC(4)
C(4)ꢂC(5)
C(5)ꢂO(2)
C(4)ꢂC(39)
C(2)ꢂC(16)
C(16)ꢂC(17)
C(1)ꢂC(27)
1.194(6)
1.493(7)
1.541(6)
1.546(7)
1.498(7)
1.218(6)
1.322(6)
1.338(6)
1.467(7)
1.506(7)
O(1)ꢂC(1)ꢂC(2)
C(1)ꢂC(2)ꢂC(3)
C(2)ꢂC(3)ꢂC(4)
C(3)ꢂC(4)ꢂC(5)
C(4)ꢂC(5)ꢂO(2)
C(4)ꢂC(39)ꢂC(40)
C(2)ꢂC(16)ꢂC(17)
C(1)ꢂC(2)ꢂC(16)
C(2)ꢂC(3)ꢂC(6)
C(4)ꢂC(5)ꢂC(33)
121.2(5)
115.0(4)
113.4(4)
117.3(4)
121.9(5)
124.2(5)
128.4(5)
123.6(5)
113.3(4)
117.2(5)
The reaction seems to involve two processes, namely, fragmentation
(a) and 1,2-addition (b) to the carbonyl group. The transient enediol (20)
undergoes cyclization in an acidic medium to afford dihydropyran (19).
The structure of compound 19 as 4-ferrocenyl-2-methyl-2,6-diphenyl-
3,4-dihydro-2H-pyran was established by X-ray diffraction analysis of
single crystals obtained by crystallization from CH2Cl2; it was confirmed
by 1H and 13C NMR spectroscopic data. The general view of molecule 19
is shown in Fig. 1. The central six-membered ring in molecule 19 adopts
the half-chair conformation; its main geometric parameters are given in
˚
Table 1. The mean Fe-C distance is equal to 2.035 A; the mean C-C bond
˚
length in the cyclopentadienyl rings is equal to 1.402 A.
It turned out that the reaction of methyllithium with 2,4-dibenzoyl-
3-ferrocenyl-2-[ferrocenyl)hydroxymethyl]-1,5-diphenylpentane-1,5-dione
(5) was also accompanied by fragmentation (a) and 1,2-addition (b) pro-
cesses.(Z,Z)-2,4-Dibenzoyl-1,3-diferrocenyl-5-phenylhexa-1,4-diene (21)
was obtained as the main reaction product (Scheme 8).
1
According to data from H NMR spectroscopy, it was isolated as a
single geometric isomer with Z,Z configurations of the double bonds.

2306
E. I. Klimova et al.
Scheme 8. Plausible mechanism for the formation of compound 21 from the reac-
tion of 2,4-dibenzoyl-3-ferrocenyl-2-[(ferrocenyl)hydroxymethyl]-1,5-diphenyl-
pentane-1,5-dione 5 with methyllithium.
The structure of this compound was established by X-ray diffraction
analysis of single crystals obtained by crystallization from CH2Cl2; it
was confirmed by data from mass, IR, and 1H and 13C NMR
spectroscopy. The general view of molecule 21 is shown in Fig. 2. The
main geometric parameters are given in Table 1.
Figure 2. Structure of 21 as determined by X-ray crystallography.

Fragmentation of 2,4-Dibenzoylferrocenyl-1,5-diones
2307
It is noteworthy that the reactions of methyllithium with the coupling
products of ferrocenecarbaldehyde with dibenzoylmethane, which are
accompanied by simultaneous fragmentation and 1,2-addition, occur
with high diastereoselectivity. The major reaction products (8, 19, and
21) were isolated in single diastereomeric or geometrical forms. The for-
mation of small amounts of other isomeric products cannot be ruled out;
however, they have not been detected.
CONCLUSIONS
The results of the present work demonstrate that the ability of the coup-
ling products of ferrocenecarbaldehyde with dibenzoylmethane to
undergo simultaneous fragmentation with abstraction of the benzoyl
fragments under the action of methyllithium and 1,2-addition of the
latter to the remaining carbonyl groups makes these compounds con-
venient starting materials for the synthesis of ferrocene-containing sub-
stances that are otherwise accessible only with difficulty. Of particular
interest is a new method of synthesis of ferrocenyl(diphenyl)-3,4-
dihydro-2H-pyran (19) as a representative of potentially biologically
active compounds. Synthesis of 2,4-dibenzoyl-1,3-diferrocenyl-5-phenyl-
hexa-1,4-diene (21) is also worth noting, as it opens new prospects for
application in the field of electrochemistry and physical optics and pro-
vides a new and simple access to bridged heterocyclic structures. In our
opinion, the ability to undergo fragmentation under the action of organo-
lithium compounds together with their 1,2-addition to the carbonyl
groups is of general character and is typical of other coupling products
of aromatic aldehydes with 1,3-diaryl-b-diketones. These reactions are
promising as new and simple methods of synthesis of diarylbuta-1,3-
dienes, cross-conjugated trienes, and triaryldihydro-2H-pyrans, 2,4-
diacylhexa-1,4-dienes.
EXPERIMENTAL
1
The H and 13C NMR spectra were recorded on a Unity Inova Varian
spectrometer (300 and 75 MHz) for solutions in CDCl3, with Me4Si as
the internal standard. The IR spectra were measured on a Specord IR-75
instruments for KBr pellets. The mass spectra were obtained on a Varian
MAT CH-6 instrument (EI MS, 70 eV). Elementar Analysen systeme
GmbH was used for elemental analyses. All the solvents were dried accord-
ing to standard procedures and were freshly distilled before use. Column
chromatography and thin-layer chromatography (TLC) were carried out
on alumina (Brockmann activity III). The following reagents were

2308
E. I. Klimova et al.
purchased from Aldrich: dibenzoylmethane, 98%; ferrocenecarboxalde-
hyde, 98%; methyllithium, 1.6 M solution in diethyl ether; acetic acid, gla-
cial, 99.99%; piperidine, 99%; and pyridine, 99%.
Condensation of Ferrocenecarboxaldehyde with Dibenzoylmethane
A mixture of FcCHO (4.3 g, 0.02 mol), dibenzoylmethane (6.72 g,
0.03 mol), piperidine (1 mL), pyridine (1 mL), and AcOH (2 mL) in dry
benzene (100 mL) was refluxed for 6 h. The reaction mixture was washed
with 5% HCl to remove the amines, and the organic layer was concen-
trated to dryness. Diethyl ether (100 mL) was added to the residue, and
the precipitate was filtered off and dried on a filter to give 2-ferrocenyl-
methylidene1,3-diphenylpropan-1,3-dione (3). The ethereal filtrate was
concentrated, and the residue was chromatographed on Al2O3 (hexane–
dichloromethane, 1:1) to give 2,4-dibenzoyl-3-ferrocenyl-1,5-diphenyl-
pentan-1,5-dione (4) and 2,4-dibenzoyl-3-ferricenyl-2-[(ferrocenyl)
-hydroxymethyl]-1,5-diphenylpentane-1,5-dione (5a,b).
Data
2-Ferrocenylmethylidene-1,3-diphenylpropane-1,3-dione (3): violet crystals,
yield 4.2 g (50%), mp 203–204 ꢁC. IR (KBr): 819, 848,1102, 1480, 1645,
.
1668, 1695, 1712, 1820, 3030 cmꢂ1 1H NMR (300 MHz, CDCl3):
d ¼ 4.18 (s, 5H, C5H5), 4.29 (m, 2H, C5H4), 4.40 (m, 2H, C5H4), 7.46–
8.01 (m, 10H, 2 C6H5). MS (EI, 70 eV): m=z ¼ 420 [M]þ . Anal. calcd
for C26H20FeO2: C, 74.30; H, 4.80; Fe, 13.29. Found: C, 74.21; H,
4.97; Fe, 13.44.
2,4-Dibenzoyl-3-ferrocenyl-1,5-diphenylpentane-1,5-dione (4): orange
powder, yield 2.6 g (20%), mp 242–244ꢁC. IR (KBr): 798, 829,
835,1100, 1467, 1688, 1720, 2921, 3024 cmꢂ1 1H NMR (300 MHz,
.
CDCl3): d ¼ 3.32 (d, J ¼ 7.2 Hz, 2 H, 2 CH), 4.12 (t, J ¼ 7.2 Hz, 1 H,
CH), 4.04 (s, 5 H, C5H5), 4.17 (m, 2H, C5H4), 4.32 (m, 2H, C5H4). MS
(EI, 70 eV): m=z ¼ 644 [M]þ . Anal. calcd for C41H32FeO4: C, 76.40; H,
5.00; Fe, 8.67. Found: C, 76.59; H, 5.13; Fe 8.48.
2,4-Dibenzoyl-3-ferrocenyl-2-[(ferrocenyl)hydroxymethyl]-1,5-diphenyl-
pentane-1,5-dione (5a,b): orange powder, yield 2.21 g (13%), two
diastereomers (ꢀ1:1), mp 303–305 ꢁC. IR (KBr): 806, 811, 839, 1106,
1
1444, 1663, 1722, 2929, 3004, 3332 cmꢂ1. H NMR (300 MHz, CDCl3):
d ¼ 1.98 (bs, 1 H, OH), 2.13 (bs, 1 H, OH), 3.16 (d, J ¼ 6.9 Hz, 1 H,
CH), 3.31 (d, J ¼ 6.3 Hz, 1 H, CH), 4.17 (d, J ¼ 6.9 Hz, 1 H, CH), 4.28
(d, J ¼ 6.3 Hz, 1 H, CH), 4.00 (s, 5 H, C5H5), 4.06 (s, 5 H, C5H5), 4.08
(s, 5 H, C5H5), 4.11 (s, 5 H, C5H5), 4.14 (m, 2H, C5H4), 4.21 (m, 4H,

Fragmentation of 2,4-Dibenzoylferrocenyl-1,5-diones
2309
C5H4), 4.24 (m, 2H, C5H4), 4.29 (m, 2H, C5H4), 4.35 (m, 2H, C5H4), 5.34
(s, 1 H, CH), 5.42 (s, 1 H, CH). MS (EI, 70 eV): m=z ¼ 858 [M]þ . Anal.
calcd for C52H42Fe2O5: C, 72.74; H, 4.93; Fe, 13.01. Found: C, 72.57; H,
5.05; Fe, 12.87.
Condensation of 2-Ferrocenylmethylidene-1,3-diphenylpropane-1,3-dione
(3) with Dibenzoylmethane
A mixture of (3) (1.3 g, 0.003 mol), dibenzoylmethane (0.67 g, 0.003 mol),
piperidine (0.3 mL), pyridine (0.3 mL), and AcOH (0.6 mL) in dry
benzene (100 mL) was refluxed for 6 h. The reaction mixture was washed
with 5% HCl to remove the amines, and the organic layer was concen-
trated. Ethanol (50 mL) was added to the residue, and the precipitate
was filtered off and dried on a filter to give 2,4-dibenzoyl-3-ferrocenyl-
1,5-diphenylpentane-1,5-dione (4): yield 1.18 g (61%), orange powder,
mp 242–243 ꢁC.
2,4-Dibenzoyl-3-ferrocenyl-2-[(ferrocenyl)hydroxymethyl]-1,5-
diphenylpentane-1,5-dione (5a,b)
Analogous to the previous procedure, the reaction of 4 (0.65 g, 0.001 mol)
with ferrocenecarboxaldehyde (0.32 g, 0.0015 mol) (0.1 mL piperidine,
0.1 mL pyridine, 0.2 mL AcOH) in 50 mL of dry benzene and subsequent
workup afforded compound (5a,b): yield 0.42 g (49%), orange powder,
ꢁ
mp 304–306 C.
Reaction of 2-Ferrocenylmethylidene-1,3-diphenylpropane-1,3-dione (3)
with Methyllithium
Method A
Ethereal solution of MeLi (1.6 M, 30 mL) was added dropwise with stirring
to a solution of compound 3 (2.95 g, 7 mmol) in dry benzene (100 mL) in an
inert dry atmosphere at ambient temperature. The reaction mixture was
stirred for 3 h and quenched with water (50 mL). The organic layer was
separated, washed with water (2 ꢃ 20 mL), and dried with Na2SO4. The
solvent was distilled off in vacuo. Glacial acetic acid (50 mL) was added
to the residue, and the mixture was boiled under reflux for 5 min and
cooled. Then it was diluted with benzene (50 mL) and washed with water
(2 ꢃ 20 mL) and 5% aq. NaHCO3. The solvent was distilled off in vacuo,

2310
E. I. Klimova et al.
and the residue was chromatographed on a column with alumina (Brock-
mann activity III) in hexane to yield compounds 6–11.
Data
a-Methylstyrene (6): colorless oil, yield 0.7 g (8%), n2D0 1.5381.
3-Ferrocenyl-1-phenyl-2-propenone (7): violet crystals, yield 0.11 g
ꢁ
(5%), mp 139 C.[10] IR (KBr): 700, 986, 1108, 1566, 1647, 1703,
1
3064 cmꢂ1. H NMR (300 MHz, CDCl3): d ¼ 4.23 (s, 5 H, C5H5), 4.54
=
(m, 2 H, C5H4), 4.66 (m, 2 H, C5H4), 7.13 (d, J ¼ 15.3 Hz, 1 H, CH ),
=
7.75 (d, J ¼ 15.3 Hz, 1 H, CH ), 7.52 (m, 3 H, C6H5), 7.97 (m, 2 H,
C6H5). 13C NMR (75 MHz, CDCl3): d ¼ 69.32, 71.81 (C5H4), 70.23
=
(C5H5), 79.74 (CipsoFc), 119.63, 128.34 (2 CH ), 128.49, 132.31, 146.73
þ
=
(C6H5), 138.98 (Cipso), 190.52 (C O). MS (EI, 70 eV): m=z ¼ 316 [M] .
Anal. calcd. for C19H16FeO: C, 72.17; H, 5.10; Fe, 17.66. Found: C,
72.29; H, 5.03; Fe, 17.82.
3,5-Diferrocenyl-1-phenyl-4-(1-phenylvinyl)cyclohexene (8): orange
crystals, yield 0.13 g (3%), mp 186–187 C.[9] 1H NMR (300 MHz,
ꢁ
CDCl3): d ¼ 2.23 (dd, J ¼ 10.5, 15.9 Hz, 1 H, CH2), 2.69 (dd, J ¼ 5.7,
15.9 Hz, 1 H, CH2), 2.81 (m, 1 H, CH5), 3.21 (dd, J ¼ 11.4, 12.9 Hz, 1
H, CH4), 3.50 (dd, J ¼ 1.8, 11.4, 12.9 Hz, 1 H, CH3), 4.12 (s, 5 H,
C5H5), 4.18 (s, 5 H, C5H5), 3.77 (m, 1 H, C5H4), 3.82 (m, 1 H, C5H4),
3.96 (m, 2 H, C5H4), 3.99 (m, 1 H, C5H4), 4.03 (m, 2 H, C5H4), 4.08
=
(m, 1 H, C5H4), 5.11 (s, 1 H, CH2 ), 5.33 (s, 1 H, CH2 ), 6.74 (d,
=
=
J ¼ 1.8 Hz, 1 H, CH ), 6.52 (m, 2 H, C6H5), 6.92–7.64 (m, 8 H,
C6H5). MS (EI, 70 eV): m=z ¼ 656 [M]þ . Anal. calcd. for C42H40Fe2:
C, 76.84; H, 6.14; Fe, 17.02. Found: C, 76.71; H, 6.23; Fe, 16.88.
3-Ferrocenylmethylidene-2,4-diphenylpenta-1,4-diene (9): orange
ꢁ
powder, yield 1.6 g (55%), mp 124–125 C. IR (KBr): 758, 821, 846,
996, 1101, 1049, 1186, 1225, 1335, 1606, 1649, 2967, 3085 cmꢂ1 1H
.
NMR (300 MHz, CDCl3): d ¼ 4.02 (s, 5 H, C5H5), 4.12 (m, 2 H,
=
C5H4), 4.28 (m, 2 H, C5H4), 5.04 (d, J ¼ 1.2 Hz, 1 H, CH2 ), 5.23 (d,
=
=
J ¼ 1.2 Hz, 1 H, CH2 ), 5.26 (d, J ¼ 1.5 Hz, 1 H, CH2 ), 5.90 (d,
=
=
J ¼ 1.5 Hz, 1 H, CH2 ), 6.21 (s, 1 H, CH ), 7.28–7.44, 7.63–7.68
(m, 10 H, 2 C6H5). 13C NMR (75 MHz, CDCl3): d ¼ 68.95 (C5H5),
=
69.13, 69.66 (C5H4), 81.16 (CipsoFc), 115.87, 115.94 (2 CH2 ), 127.19
=
(CH ), 126.25, 127.77, 128.01, 128.52, 129.05, 130.64 (2 C6H5), 138.68,
139.18, 142.17, 146.25, 150.24 (5 C). MS (EI, 70 eV): m=z ¼ 416 [M]þ .
Anal. calcd. for C28H24Fe: C, 80.77; H, 5.81; Fe, 13.42. Found: C,
80.64; H, 5.98; Fe, 13.64.
2-Benzoyl-1-ferrocenyl-3-phenylbuta-1,3-diene (10a,b): orange pow-
der, yield 0.2 g (7%), (Z,E)-isomers (ꢀ1:1), mp 132–133 ꢁC. IR

Fragmentation of 2,4-Dibenzoylferrocenyl-1,5-diones
2311
(KBr): 812, 824, 883, 895, 1002, 1030, 1050, 1105, 1180, 1251, 1340, 1425,
1606, 1658, 1699, 1713, 2929, 2963, 3091 cmꢂ1 1H NMR (300 MHz,
.
CDCl3): d ¼ 4.11 (s, 5 H, C5H5), 4.19 (s, 5 H, C5H5), 3.95 (m, 2 H,
C5H4), 4.16 (m, 2 H, C5H4), 4.29 (m, 2 H, C5H4), 4.42 (m, 2 H, C5H4),
=
=
4.97 (d, 1 H, J ¼ 1.2, CH2 ), 5.04 (d, 1 H, J ¼ 0.9, CH2 ), 5.18 (d, 1
=
=
=
H, J ¼ 1.2, CH2 ), 5.26 (d, 1 H, J ¼ 0.9, CH2 ), 6.34 (s, 1H, CH ),
6.67 (s, 1H, CH ), 6.89–7.63 (m, 20 H, 4 C6H5). 13C NMR (75 MHz,
=
CDCl3): d ¼ 68.86, 68.91, 69.85, 70.24 (2 C5H4), 69.49, 69.66 (2 C5H5),
=
79.89, 80.04 (2 CipsoFc), 114.11, 116.17 (2 CH2 ), 124.45, 124.59 (2
=
CH ), 126.45, 126.58, 127.12, 127.36, 127.54, 128.43, 128.51, 128.69,
129.18, 129.72, 131.14, 131.19 (4 C6H5), 136.58, 136.63, 138.45, 138.71,
=
139.11, 139.36, 141.21, 141.83 (8 C), 199.87, 201.08 (2 C O). MS (EI,
70 eV): m=z ¼ 418 [M]þ . Anal. calcd. for C27H22FeO: C, 77.52; H,
5.30; Fe, 13.35. Found: C, 77.67; H, 5.18; Fe, 13.49.
2-Benzoyl-1-ferrocenyl-3-methylinden (11): orange powder, yield
ꢁ
0.25 g (8%), mp 127–128 C. IR (KBr): 791, 846, 1103, 1054, 1190,
1253, 1345, 1606, 1649, 1667, 2979, 3083 cmꢂ1
.
1H NMR (300 MHz, CDCl3): d ¼ 2.27 (s, 3 H, CH3), 4.15 (s, 5 H,
C5H5), 3.93 (m, 1 H, C5H4), 4.00 (m, 1 H, C5H4), 4.08 (m, 1 H, C5H4),
4.21 (m, 1 H, C5H4), 4.06 (s, 1 H, CH), 6.93–7.38 (m, 9 H, C6H4,
C6H5). 13C NMR (75 MHz, CDCl3): d ¼ 18.94 (CH3), 36.38 (CH),
69.59 (C5H5), 67.93, 68.01 (C5H4), 93.11 (CipsoFc), 127.27, 127.70,
128.34, 129.15, 131.69 (C6H4, C6H5), 126.90, 135.97, 137.98, 141.65,
þ
=
142.84 (5 C), 200.62 (C O). MS (EI, 70 eV): m=z ¼ 418 [M] . Anal.
calcd. for C27H22FeO: C, 77.52; H, 5.30; Fe, 13.35. Found: C, 77.40;
H, 5.42; Fe, 13.17.
Method B
Analogously, a solution of compound 3 (2.10 g, 5 mmol) in dry benzene
(70 mL) was treated with methyllithium (1.6 M solution in diethyl ether,
ꢁ
20 mL) for 3 h at ꢀ20 C and quenched with water (20 mL), and the
organic layer was washed with water and concentrated. Column chroma-
tography of the residue on alumina (Brockmann activity III) in hexane–
benzene (2:1) afforded compounds 7, 2, 13, 16, and 17.
Data
ꢁ
2-Phenyl-2-propanol (13): colorless oil, yield 0.48 g (22%), mp 32–34 C.
3-Ferrocenꢁyl-1-phenyl-2-propenone (7): violet crystals, yield 0.08 g
(7%), mp 139 C.

2312
E. I. Klimova et al.
1-Ferrocenyl-3-phenyl-1-buten-3-ol (12): orange powder, yield 0.5
ꢁ
1
(30%), mp 132–134 C. H NMR (300 MHz, CDCl3): d ¼ 1.66 (s, 3 H,
CH3), 1.96 (bs, 1 H, OH), 4.08 (s, 5 H, C5H5), 4.18–4.30 (m, 4 H,
=
C5H4), 6.10 (d, 1 H, J ¼ 16.0 Hz, CH ), 6.40 (d, 1 H, J ¼ 16.0 Hz,
þ
=
CH ), 7.20–7.42 (m, 5 H, Ph). MS (EI, 70 eV): m=z ¼ 332 [M] . Anal.
calcd. for C20H20FeO: C, 72.30; H, 6.07; Fe, 16.81. Found: C, 72.26;
H, 6.01; Fe, 16.77.
2-Benzoyl-1-ferrocenyl-3-phenyl-1-buten-3-ol (17a,b): orange powder,
yield 0.22 g (10%), (Z,E)-isomers (ꢀ1:1), mp 211–212 ꢁC. IR (KBr): 810,
1101, 1157, 1264, 1445, 1529, 1645, 1714, 2930, 3090, 3340–3450 cmꢂ1
.
1H NMR (300 MHz, CDCl3): d ¼ 1.92 (s, 3 H, CH3), 1.98 (s, 3 H,
CH3), 2.75 (bs, 1 H, OH), 2.89 (bs, 1 H, OH), 4.14 (s, 5 H, C5H5), 4.19
(s, 5 H, C5H5), 4.25 (m, 2 H, C5H4), 4.28 (m, 4 H, C5H4), 4.32 (m, 2
=
=
H, C5H4), 6.49 (s, 1 H, CH ), 6.56 (s, 1 H, CH ), 7.11–7.52 (m, 10 H,
2 Ph). 13C NMR (75 MHz, CDCl3): d ¼ 27.46 (CH3), 29.14 (CH3),
68.89, 68.95, 69.78, 69.83 (2 C5H4), 69.30, 69.41 (2 C5H5), 72.47, 72.56
=
(2 C-OH), 80.31, 80.67 (2 CipsoFc), 124.89, 125.40 (2 CH ), 138.97,
=
139.32, 144.34, 145.59 (4 Cipso), 208.12, 210.22 (2 C O). MS (EI,
70 eV): m=z ¼ 436 [M]þ . Anal. calcd. for C27H24FeO2: C, 74.32; H,
5.54; Fe, 12.80. Found: C, 74.56; H, 5.39; Fe, 12.71.
3-Ferrocenylmethylidene-2,4-diphenylpentan-2,4-diol (16a,b): orange
ꢁ
powder, yield 1.47 g (65%), two diastereomers (ꢀ2:1), mp 224–226 C.
IR (KBr): 788, 848, 1104, 1163, 1247, 1451, 1533, 1641, 1667, 2923,
1
3079, 3334–3445 cmꢂ1. H NMR (300 MHz, CDCl3) for 16a: d ¼ 1.87
(s, 3 H, CH3), 1.96 (s, 3H, CH3), 2.99 (bs, 2 H, OH), 3.99 (s, 5 H,
C5H5), 3.88 (m, 2 H, C5H4), 3.96 (m, 1 H, C5H4), 4.13 (m, 1 H, C5H4),
1
6.44 (s, 1 H, CH ), 7.19–7.60 (m, 10 H, 2 Ph). H NMR (300 MHz,
=
CDCl3) for 16b: d ¼ 1.71 (s, 3 H, CH3), 1.79 (s, 3H, CH3), 2.45 (bs, 2
H, OH), 4.05 (s, 5 H, C5H5), 3.20 (m, 1 H, C5H4), 3.49 (m, 1 H,
=
C5H4), 4.24 (m, 2 H, C5H4), 6.69 (s, 1 H, CH ), 7.40–7.92 (m, 10 H, 2
Ph). MS (EI, 70 eV): m=z ¼ 452 [M]þ . Anal. calcd. for C28H28FeO2: C,
74.34; H, 6.24; Fe, 12.35. Found: C, 74.23; H, 6.35; Fe, 12.21.
Reaction of 2,4-Dibenzoyl-3-ferrocenyl-1,5-diphenylpentan-1,5-dione (4)
with MeLi
A solution of MeLi (1.6 M solution in diethyl ether, 10 mL) was added
dropwise in an inert atmosphere to a stirred solutiꢁon of compound 4
(0.97 g, 0.0015 mol) in dry benzene (50 mL) at 20 C for 30 min. The
mixture was stirred for an additional 6 h, and the excess of MeLi was
quenched by addition of water (50 mL). The organic layer was separated,
dried with Na2SO4, and concentrated. The residue was chromatographed

Fragmentation of 2,4-Dibenzoylferrocenyl-1,5-diones
2313
on Al2O3 (hexane–ether, 4:1) to give 0.22 g (62%) of the a-methylstyrene
(6) as a colorless oil (n2D0 1.5382), and 0.52 g (80%) of the 4-ferrocenyl-2-
methyl-2,6-diphenyl-3,4-dihydro-2H-pyran (19).
Compound (19): orange crystals, mp 118–119 ꢁC. IR (KBr): 816, 891,
1101, 1148, 1254, 1647, 1673, 2867, 2916, 3032 cmꢂ1. 1H NMR (300 MHz,
CDCl3): d ¼ 1.74 (s, 3 H, CH3), 2.54 (dd, J ¼ 5.4, 15.3 Hz, 1 H, CH2),
3.05 (dd, J ¼ 8.7, 15.3 Hz, 1 H, CH2), 3.69 (m, 1 H, CH), 4.10 (s, 5 H,
C5H5), 4.14 (m, 2 H, C5H4), 4.31 (m, 2 H, C5H4), 6.84 (d, J ¼ 7.2 Hz, 1
H, CH ), 7.03–7.47 (m, 10 H, 2 C6H5). 13C NMR (75 MHz, CDCl3):
=
d ¼ 21.24 (CH3), 34.15 (CH2), 43.26 (CH), 58.93 (C), 69.25 (C5H5),
=
68.93, 70.12 (C5H4), 82.03 (CipsoFc), 124.14 (CH ), 126.31, 126.63,
127.10, 127.39, 128.45, 130.14 (2 C6H5), 138.54, 142.91, 143.67 (3 C).
MS (EI, 70 eV): m=z ¼ 434 [M]þ . Anal. calcd. for C28H26FeO: C,
77.42; H, 6.03; Fe, 12.87. Found: C, 77.23; H, 6.19; Fe, 12.68.
Reaction of 2,4-Dibenzoyl-3-ferrocenyl-2-[(ferrocenyl)hydroxymethyl]-1,5-
diphenylpentane-1,5-dione (5a,b) with MeLi
Analogous to the previous procedure, the reaction of 5a,b (1.29 g,
0.0015 mol) with MeLi (1.ꢁ6 M solution in diethyl ether, 10 mL) in
50 mL of dry benzene (20 C, 10 h) and subsequent workup afforded
compound 6, 0.1 g (55%), and compound (21), 0.74 g (67%).
(Z,Z)-2,4-Dibenzoyl-1,3-diferrocenyl-5-phenylhexa-1,4-diene
ꢁ
(21):
violet crystals, mp 242–243 C. IR (KBr): 819, 888, 1101, 1154, 1248,
1645, 1675, 2883, 2928, 3039 cmꢂ1 1H NMR (300 MHz, CDCl3):
.
d ¼ 1.87 (s, 3 H, CH3), 3.79 (s, 1 H, CH), 4.04 (s, 5 H, C5H5), 4.17 (s,
5 H, C5H5), 3.78 (m, 2 H, C5H4), 3.89 (m, 2 H, C5H4), 4.21 (m, 2 H,
=
C5H4), 4.38 (m, 2 H, C5H4), 6.64 (s, 1 H, CH ), 7.03–7.79 (m, 15 H, 3
C6H5). 13C NMR (75 MHz, CDCl3): d ¼ 20.03 (CH3), 39.22 (CH),
69.13, 69.84 (2 C5H5), 68.37, 68.91, 70.43, 71.07 (2 C5H4), 80.11, 80.43
=
(2 CipsoFc), 123.94 (CH ), 126.33, 126.48, 126.78, 127.23, 127.65,
128.04, 129.61, 130.04, 131.13 (3 C6H5), 128.78, 136.34, 137.18, 137.92,
=
138.16, 141.91 (6 C), 203.15, 205.07 (2 C O). MS (EI, 70 eV): m=z ¼
734 [M]þ . Anal. calcd. for C46H38Fe2O2: C, 75.22; H, 5.21; Fe, 15.21.
Found: C, 75.39; H, 5.06; Fe, 15.38.
X-ray Crystal Structure Analysis of (19) and (21)
Crystals were obtained from CH2Cl2. The unit-cell parameters and the
X-ray diffraction intensities were recorded on a Bruker Smart Apex
CCD diffractometer. The structures of compounds were solved by direct
methods (SHELXS-97[11]) and refined using full-matrix least squares on F2.

2314
E. I. Klimova et al.
Crystal data for C28H26FeO (19): M ¼ 434.34 gꢄmolꢂ1, triclinic P-1,
a ¼ 73.828(1)ꢁ,
˚
A,
a ¼ 7.829(1),
b ¼ 10.455(1),
c ¼ 14.744(1)
ꢁ
ꢁ
3
˚
b ¼ 82.515(2) , c ¼ 69.288(1) , V ¼ 1083.5(1) A , T ¼ 293(2) K, Z ¼ 2,
3
˚
q ¼ 1.331 Mg=m , k (Mo–Ka) ¼ 0.71073 A, F(000) ¼ 456, absorption
coefficient 0.713 mm ꢂ 1, crystal size 0.236 ꢃ 0.21 ꢃ 0.088 mm3, index
ranges
ꢂ9 ꢅ h ꢅ 9,
ꢂ12 ꢅ k ꢅ 12,
ꢂ17 ꢅ l ꢅ 17, scan range
2.15 ꢅ h ꢅ 25.02ꢁ, 3836 independent reflections, Rint ¼ 0.0464, 12934 total
reflections, 272 refinable parameters, final
R indices [I > 2r(I)]
R1 ¼ 0.0457, wR2 ¼ 0.0658,
R
indices (all data) R1 ¼ 0.0643,
ꢂ 3
˚
wR2 ¼ 0.0686, largest difference peak and hole 0.612=ꢂ0.230 eA
.
Crystal data for C46H38Fe2O2 (21): M ¼ 734.46 gꢄmol ꢂ 1, monoclinic
P21=n, a ¼ 6.219(1), b ¼ 26.756(2), c ¼ 21.105(2) A, a ¼ 90ꢁ,
˚
b ¼ 94.666(2)ꢁ, c ¼ 90ꢁ, V ¼ 3500.1(7) A , T ¼ 293(2) K, Z ¼ 4,
3
˚
3
˚
q ¼ 1.394 Mg=m , k (Mo–Ka) ¼ 0.71073 A, F(000) ¼ 1528, absorption
coefficient 0.868 mmꢂ1, crystal size 0.648 ꢃ 0.026 ꢃ 0.024 mm3, index
ranges
ꢂ7 ꢅ h ꢅ 7,
ꢂ31 ꢅ k ꢅ 31,
ꢂ24 ꢅ l ꢅ 25, scan range
1.80 ꢅ h ꢅ 25.01ꢁ, 6176 independent reflections, Rint ¼ 0.1488, 28148 total
reflections, 452 refinable parameters, final
R indices [I > 2r(I)]
R1 ¼ 0.0724, wR2 ¼ 0.1090,
R
indices (all data) R1 ¼ 0.1454,
ꢂ 3
˚
wR2 ¼ 0.1252, largest difference peak and hole 0.497=ꢂ0.323 eA
.
Supplementary material: crystallographic data for the structural
analysis have been deposited with the Cambridge Crystallographic Data
Centre, CCDC no. 649254 for compound 19 and no. 649253 for
compound 21. Copies of this information may be obtained free of charge
from the Director, CCDC, 12 Union Road, Cambrige CB2 IEZ, UK
(fax: þ 44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
ACKNOWLEDGMENTS
This work was supported by the grant DGAPA-UNAM IN 207606
(Mexico). E. A. Vazquez Lopez and R. I. Del Villar Morales are
acknowledged for their technical assistance.
REFERENCES
´
1. Klimova, E. I.; Klimova, T.; Mendez Stivalet, J. M.; Alvarez Toledano, C.;
Toscano, A. R.; Hernandez Ortega, S.; Ruız Ramırez, L.; Backinowsky,
´
´
´
´
´
L. V.; Martınez Garcıa, M. Sıntesis and some chemical transformations of
(Z)- and (E)-2-acetyl-1-ferrocenyl-3-methylbuta-1,3-dienes: A new type of
cationic cycloaddition. Eur. J. Org. Chem. 2004, 1714–1723.

Fragmentation of 2,4-Dibenzoylferrocenyl-1,5-diones
2315
´
2. Klimova, E. I.; Klimova, B. T.; Mendez Stivalet, J. M.; Toscano, R. A.;
Alvarez, T. C.; Martınez, M. G. Cross-conjugated 3-ferrocenylmethylidene-
´
2,4-dimethylpenta-1,4-diene in cationic cycloaddition and proton-catalyzed
cyclodimerization reactions. J. Organomet. Chem. 2004, 689, 3232–3241.
´
´
´
´
3. Klimova, E. I.; Klimova Berestneva, T.; Martınez Garcıa, M.; Ruız Ramırez,
L. Synthesis and some chemical properties of s-cis-diferrocenyltrienes: The
role of stereoelectronic factors in cationic dimerization reactions. J. Organo-
met. Chem. 1999, 579, 30–37.
´
´
´
4. Klimova, E. I.; Martınez Garcıa, M.; Klimova, T.; Mendez Stivalet, J. M.
The behaviour of 3-ferrocenyl-1-methyl-1,2-pentamethyleneallyl- and 1,5-
diferrocenyl-3-methyl-2,4-tetramethylene-1,4-dienyl carbocations in the
cationic dimerization of 1,3-dienes. J. Organomet. Chem. 2000, 602, 105–114.
5. Heo, R. W.; Sonoza, F. B.; Lee, T. R. Soluble conjugated polymers that
contain ferrocenylene units in the backbone. J. Am. Chem. Soc. 1998, 120,
1621–1623.
6. Bildstein, B.; Skibar, W.; Schweiger, M.; Kapacka, H.; Wurst, K. In situ
=
= = = = =
synthesis of the first C7 cumulene (Fc2)C C C C C C C(Fc2) via depro-
tonation of its conjugate acid [(Fc2)C7H[(Fc2)]þ BF4ꢂ. J. Organomet. Chem.
2001, 622, 135–141.
7. Liu, J.; Castro, R.; Abboud, K.; Kaifer, A. E. Novel Ferrocenyl polyene deri-
vatives and their binding to unmodified cyclodextrines. J. Org. Chem. 2000,
65, 6973–6977.
8. Hall, C.; Ferrocenes, D.; Togni, A.; Hayashi, T. (Eds.): VCH Publishers:
New York, 1995.
9. Perevalova, E. G.; Klimova, E. I.; Kruchkova, V. V.; Pushin, A. N. Aryl,
ferrocenyl-1,3-butadienes. Zh. Obshch. Khim. 1989, 59, 873–881.
10. Toma, S.; Salisova, M. Application of internal Michael addition to the
synthesis of [n]-ferrocenophane derivatives, 1: Synthesis of [3]-, [4]- and [7]-
ferrocenophane derivatives. J. Organomet. Chem. 1973, 57, 191–195.
11. Sheldrick, G. M. SHELXS-97: Program for the Solution and Refinement of
Crystal Structures; University of Go¨ttingen: Germany, 1997.