Stereoselective synthesis of trans-β-substituted γ-ferrocenyl- γ-butyrolactones via ammonium ylides

Article abstract of DOI:10.1055/s-2005-872143

trans-β-substituted γ-ferrocenyl-γ-butyrolactones were prepared via the reaction of quaternary ammonium salts with electron-deficient trisubstituted alkene 1 under the optimum conditions. Moderate to good yields and excellent trans stereoselectivity were achieved for the new compounds 2-10. The X-ray crystal structure of 2a was determined and all the products were characterized by ¹H NMR, ¹³C NMR, FAB-MS, IR and HRMS spectra. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2005-872143

PAPER
2851
Stereoselective Synthesis of trans-b-Substituted g-Ferrocenyl-g-butyrolactones
via Ammonium Ylides
t
rans-b-Substitu
i
ted g-F
n
errocenyl-g-
g
butyrolactone
s
Shi,a Yao Han,a Zhanjun Yang,a Weimin Liu,b Yongmin Liang*a,b
a
Department of Chemistry and State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, P. R. China
Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
Fax +86(931)8912582; E-mail: liangym@lzu.edu.cn
b
Received 28 March 2005; revised 23 May 2005
no nitrogen ylide-attended versions of the synthesis of
trans-b-substituted g-ferrocenyl-g-butyrolactones.
Abstract: trans-β-substituted g-ferrocenyl-g-butyrolactones were
prepared via the reaction of quaternary ammonium salts with elec-
tron-deficient trisubstituted alkene 1 under the optimum conditions.
Moderate to good yields and excellent trans stereoselectivity were
achieved for the new compounds 2–10. The X-ray crystal structure
of 2a was determined and all the products were characterized by 1H
NMR, 13C NMR, FAB-MS, IR and HRMS spectra.
We present here a strategy for the efficient and highly ste-
reoselective synthesis of trans-b-substituted g-ferrocenyl-
g-butyrolactones via ammonium ylide routes. This strate-
gy for the synthesis of ferrocenyl butyrolactones has a
number of advantages over common methods of generat-
ing b,g-trans-disubstituted g-butyrolactones:9 there are no
transition metals involved in the reaction, and the starting
materials are readily available and conveniently handled.
We also discuss the structures of these ferrocenyl butyro-
lactones. Specially, the configuration of product 2a was
determined by the X-ray structural analysis.
Key words: trans-b-substituted
g-ferrocenyl-g-butyrolactones,
ammonium ylides, electron-deficient, stereoselectivity, mechanism
Much attention has been focused on compounds bearing
the substituted g-butyrolactone moiety because of their
far-ranging existence in natural products.1 Moreover,
functionalized g-butyrolactones have been also employed
as key intermediates for the synthesis of a wide range of
bioactive compounds.2 Ferrocene derivatives have found
a number of applications in organic synthesis, as well as
in materials science.3 A large number of papers have been
published on the characterization of mono- and disubsti-
tuted derivatives of ferrocene as typical organometallic
species.4 In the course of a research program devoted to
the synthesis of ferrocene derivatives as potentially valu-
able material,5 we were interested in introducing butyro-
lactone moiety to ferrocene derivatives. Cao et al.
reported that b,g-trans-disubstituted g-butyrolactone can
be prepared via the reaction of arsenic ylides with 2,2-
dialkyl-1,3-dioxa-5-substituted-benzylidene-4,6-diones.6
Recently, a growing amount of attention has been paid to
the application of nitrogen ylides owing to the vast range
of tertiary amines that are commercially available.7 Our
group also reported some efficient synthesis methods
based on ammonium ylides.8 To our knowledge, there are
Our work started by treating electron-deficient trisubsti-
tuted alkene 1 with salt 2 in the presence of base under dif-
ferent conditions to mainly form b,g-trans-disubstituted
g-butyrolactone as shown in Scheme 1. After optimizing
the conditions, good yield (87%) and high stereoselectiv-
ity (the ratio of trans to cis diastereoisomer was above
99:1) were obtained under reflux in dichloromethane and
DMSO (4:1). Anhydrous K2CO3 proved to be the most ef-
fective and convenient base to the reaction in the solvent
system. There was little or no reaction observed at room
temperature. The results of the synthesis of ferrocenyl bu-
tyrolactones are summarized in Table 1.
The reaction worked as well for most of the salts. In en-
tries 1–5 and 7–9, the products formed were the b,g-trans-
disubstituted g-butyrolactones in good to excellent yield
and with high stereoselectivity (the ratios of trans to cis
diastereoisomers were above 99:1). The trans isomers
were formed preferentially probably due to the major ther-
modynamic stability. It was also noticed that different
O
O
O
O
O
+
base
solvent
+
N
N
O
Ph
Br–
O
Ph
1
2a
2
O
Scheme 1
SYNTHESIS 2005, No. 17, pp 2851–2856
x
x.
x
x
.
2
0
0
5
Advanced online publication: 04.08.2005
DOI: 10.1055/s-2005-872143; Art ID: F05905SS
© Georg Thieme Verlag Stuttgart · New York

2852
L. Shi et al.
PAPER
O
O
+
+
+
N
Cl–
N
N
Cl–
N
N
N
Br–
N
PhHN
(C2H5)2N
O
+
+
N
Cl–
+
N
Br–
+
N
Ph
N
N
Br–
N
N
Ph
N
Br–
Ph
Figure 1 Quaternary ammonium salts used in the study
substituted groups of the phenyl ring resulted in dramatic methylene of the salts must attach to an electron-with-
change in yields (entries 1–4). In particular, entries 2 and drawing group, such as carbonyl, cyano-, and the reaction
4 showed quite different yields of 62 and 90%, respective- is retarded by the substituents at the methylene due to the
ly. In entry 6 only a moderate stereoselectivity (the ratio steric hindrance.
of trans diastereoisomer to cis one was 66:11) was ob-
tained due to the small steric hindrance of the cyano
group.
The reaction mechanism for the formation of compound
2a is proposed as follows (Scheme 2):6 Firstly, the ylide
11, derived from ammonium salt 2, reacts with olefin 1 to
To increase the range of the salts, other ylides prepared form the trans-cyclopropane derivative 12. Compound 12
from corresponding halides were examined. Some select- reacts further with water to form trans-b-benzoyl-g-ferro-
ed examples are shown in Figure 1. All these substrates cenyl-g-butyrolactone 2a.
could not undergo the reaction. We got ferrocenyl alde-
hyde as decomposed product of the substrate 1 in most of
the experiments. These results strongly indicated that the
Table 1 Synthesis of trans-b-Substituted g-Ferrocenyl-g-butyrolactones
O
O
K2CO3
solvent
+
O
R
+
N
X–
N
O
O
O
R
Entry
1
R
X
Solvent
Yield (%)a
Productb
trans/cisc
O
O
CH2Cl2–DMSO
(4:1)
O
Br
87
>99:1
O
Fc
2a
O
2
3
4
O
2
3
Br
Br
MeCN
62
82
>99:1
>99:1
O
O
Br
Br
Fc
3a
O
O
CH2Cl2–DMSO
(4:1)
O
O
H3C
H3C
Fc
4a
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PAPER
trans-b-Substituted g-Ferrocenyl-g-butyrolactones
2853
Table 1 Synthesis of trans-b-Substituted g-Ferrocenyl-g-butyrolactones (continued)
O
O
K2CO3
solvent
+
O
R
+
N
X–
N
O
O
O
R
Entry
4
R
X
Solvent
Yield (%)a
Productb
trans/cisc
O
O
CH2Cl2–DMSO
(4:1)
O
Br
90
>99:1
O
H3CO
H3CO
Fc
5
5a
O
C2H5O
O
CH2Cl2–DMSO
(4:1)
5
Br
55
>99:1
C2H5O
Fc
O
O
6a
6
O
Fc
O
CN
CH2Cl2–DMSO
(4:1)
66
11
7a
6
NC
Cl
66:11d
O
Fc
7
O
CN
7b
O
H3C
Fc
O
7
8
Br
Br
acetone
47
65
>99:1
>99:1
H3C
O
O
8a
8
9
O
O
O
CH2Cl2–DMSO
(4:1)
O
O
O
Fc9a
O
O
CH2Cl2–DMSO
(4:1)
S
9
Br
64
>99:1
O
S
O
Fc
10
10a
a Yield of isolated product.
b Fc = ferrocenyl.
c Determined by 1H NMR spectroscopy.
d Determined by isolated yield.
Synthesis 2005, No. 17, 2851–2856 © Thieme Stuttgart · New York

2854
L. Shi et al.
PAPER
O
O
O
O
Fc
O
O
O
Fc
H
O
O
K2CO3
N
N
1
H2O
+
_
+
H
N
N
_
O
Ph
Ph
Br
COPh
12
11
2
O
O
O
O
Fc
OH
O
O
O
_
Fc
O
OH
H
CO2
_
H
COPh
Fc
COPh
H
O
O
O
H
COPh
2a
Scheme 2
Products 2–10 are air-stable compounds and are charac- Melting points were determined on a microscopic apparatus and are
1
terized by H and 13C NMR, FAB mass, IR and HRMS
uncorrected. Column chromatography was carried out on silica gel.
The NMR spectra were recorded on a Mercury 4N-PFG 1H sensitiv-
ity (plus-300) spectrometer, using CDCl3 as solvent and TMS as in-
ternal standard. The FAB mass spectra were measured on VG ZAB-
1
spectra. The H NMR spectra of products 2a–10a show
that the ferrocenyl and g-substituted groups are placed
trans to each other. The configuration of the product 2a
HS Mass spectrometer. Nicolet AVATAR 360 FT-IR spectrometer
was used for IR spectra and only major peaks are reported in cm–1.
HRMS spectra were obtained with a Bruker APEX instrument.
was assigned on the basis of the X-ray structural analy-
sis.10 An ORTEP diagram of the structure of 2a is shown
in Figure 2. In the molecule of compound 2a, the benzoyl
group and the ferrocenyl group orient in opposite direc-
tions on the central five-membered ring. The C=O, Fe–C
and C–C bonds of the butyrolactone as well as the geo-
metrical parameters of the ferrocene sandwiches, are close
to standard values.11
All reagents were used directly as obtained commercially unless
otherwise noted. All mixed solvent systems are reported as v/v so-
lutions. The electron-deficient trisubstituted alkene 1 was easily
prepared according to the literature procedures.12
Ammonium Ylides; Ammonium Salt 2; Typical Procedure
A solution of DABCO (1.12 g, 10 mmol) in THF (10 mL) was add-
ed to a solution of phenacyl bromide (1.99 g, 10 mmol) in THF (30
mL) with stirring at r.t. until the starting material had disappeared
(monitored by TLC). The mixture was filtered and the precipitates
were washed with THF (3 × 10 mL) and petroleum ether (bp 40–60
°C, 3 × 10 mL) to give the pure salt 1 as a white solid in 95% yield.
Reaction of the Electron-Deficient Trisubstituted Alkene 1 with
Ammonium Ylides To Give trans-b-Substituted g-Ferrocenyl-g-
butyrolactones; General Procedure
A suspension of the appropriate ammonium salt (0.75 mmol,
Table 1) and anhyd K2CO3 (1.5 mmol) in CH2Cl2–DMSO (4:1, 10
mL) was stirred vigorously at r.t. for 0.5 h. A solution of alkene 1
(0.5 mmol) in CH2Cl2–DMSO (4:1, 10 mL) was added to the previ-
ous mixture and the stirring continued at reflux temperature until
the reaction was completed according to TLC. The reaction was
quenched with H2O (10–15 mL) and extracted with CH2Cl2 (3 × 10
mL). The combined organic extracts were washed with H2O, brine,
and dried (MgSO4). The crude product was purified by silica gel
column chromatography using petroleum ether and EtOAc as eluent
to give the pure product (Table 1).
2a
Orange solid; mp 121–122 °C.
IR (KBr): 3070, 1759, 1688, 1598, 1581, 1447, 1196, 905 cm–1.
Figure 2 X-ray crystal structure of 2a
1H NMR (300 MHz, CDCl3): d = 7.88 (d, J = 7.8 Hz, 2 H), 7.62 (t,
J = 7.2 Hz, 1 H), 7.48 (t, J = 7.5 Hz, 2 H), 5.60 (d, J = 6.9 Hz, 1 H),
4.24 (s, 2 H), 4.17 (br s, 8 H), 2.94 (dd, J = 2.4, 8.7 Hz, 2 H).
13C NMR (75 MHz, CDCl3): d = 196.7, 174.2, 135.1, 134.1, 128.9,
128.5, 85.3, 80.3, 68.9, 68.4, 66.7, 65.4, 49.5, 33.6.
Further investigations into this process to find more effec-
tive nitrogen ylides and to prepare substituted g-butyro-
lactones are currently underway in our laboratory.
FAB+-MS: m/z = 374.
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PAPER
trans-b-Substituted g-Ferrocenyl-g-butyrolactones
2855
HRMS: m/z [M + H] calcd for C21H18FeO3: 375.0678; found:
375.0678.
1H NMR (300 MHz, CDCl3): d = 5.47 (d, J = 6.9 Hz, 1 H), 4.33 (br
s, 9 H), 3.68 (dd, J = 7.5, 15 Hz, 1 H), 2.93–2.96 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 172.1, 116.5, 81.2, 78.5, 69.4,
3a
67.9, 65.4, 33.3, 32.5.
Orange solid; mp 156–157 °C.
FAB+-MS: m/z = 295.
IR (KBr): 3095, 1757, 1684, 1583, 1417, 1205, 1150, 1069, 813
cm–1.
1H NMR (300 MHz, CDCl3): d = 7.72 (d, J = 8.4 Hz, 2 H), 7.62 (d,
J = 8.4 Hz, 2 H), 5.53 (d, J = 6.9 Hz, 1 H), 4.26 (s, 2 H), 4.18 (s, 7
H), 4.07 (br s, 1 H), 2.96 (d, J = 6.9 Hz, 2 H).
13C NMR (75 MHz, CDCl3): d = 195.8, 174.0, 133.9, 132.3, 130.0,
129.7, 85.4, 80.4, 69.2, 68.5, 67.0, 65.2, 50.0, 33.5.
HRMS: m/z [M + H] calcd for C15H13FeNO2: 296.0368; found:
296.0363.
7b
Orange solid; mp 138–139 °C.
IR (KBr): 2245, 1786, 1414, 1193 cm–1.
1H NMR (300 MHz, CDCl3): d = 5.45 (d, J = 7.5 Hz, 1 H), 4.27 (s,
9 H), 3.37 (dd, J = 9.0, 17.4 Hz, 1 H), 2.92–3.11 (m, 2 H).
FAB+-MS: m/z = 454, 452.
HRMS: m/z [M + H] calcd for C21H17BrFeO3: 452.9783; found:
452.9777.
13C NMR (75 MHz, CDCl3): d = 171.6, 117.6, 82.6, 80.1, 69.5, 69.3
66.2, 33.4, 32.7.
FAB+-MS: m/z = 295.
4a
Orange solid; mp 120–121 °C.
HRMS: m/z [M + H] calcd for C15H13FeNO2: 296.0368; found:
296.0361.
IR (KBr): 3075, 1754, 1687, 1608, 1406, 1204, 1102, 833, 813
cm–1.
1H NMR (300 MHz, CDCl3): d = 7.78 (d, J = 8.4 Hz, 2 H), 7.28 (d,
J = 8.4 Hz, 2 H), 5.60 (d, J = 6.9 Hz, 1 H), 4.23 (s, 2 H), 4.14–4.19
(m, 8 H), 2.94 (d, J = 8.7 Hz, 2 H), 2.42 (s, 3 H).
8a
Orange solid; mp 112–113 °C.
IR (KBr): 1758, 1711, 1415, 1209, 1169 cm–1.
1H NMR (300 MHz, CDCl3): d = 5.39 (d, J = 6.3 Hz, 1 H), 4.24 (br
s, 9 H), 3.40 (dd, J = 8.7, 16.2 Hz, 1 H), 2.86 (d, J = 9.0 Hz, 2 H),
2.23 (s, 3 H).
13C NMR (75 MHz, CDCl3): d = 204.6, 174.0, 85.7, 79.6, 69.0,
68.6, 66.8, 65.3, 55.1, 32.2, 29.9.
13C NMR (75 MHz, CDCl3): d = 196.3, 174.3, 145.3, 132.7, 129.6,
128.7, 85.4, 80.5, 68.8, 68.4, 66.7, 65.5, 49.5, 33.8, 21.7.
FAB+-MS: m/z = 388.
HRMS: m/z [M + H] calcd for C22H20FeO3: 389.0834; found:
389.0827.
FAB+-MS: m/z = 312.
5a
HRMS: m/z [M + H] calcd for C16H16FeO3: 313.0521; found:
313.0518.
Orange solid; mp 80–81 °C.
IR (KBr): 3094, 1779, 1669, 1599, 1417, 1316, 1175, 840, 816
cm–1.
1H NMR (300 MHz, CDCl3): d = 7.86 (d, J = 8.7 Hz, 2 H), 6.94 (d,
J = 9.0 Hz, 2 H), 5.57 (d, J = 6.6 Hz, 1 H), 4.24 (s, 2 H), 4.14 (s, 7
H), 4.09 (br s, 1 H), 3.88 (s, 3 H), 2.94 (dd, J = 3.6, 8.7 Hz, 2 H).
9a
Orange solid; mp 116–117 °C.
IR (KBr): 3131, 1781, 1671, 1566, 1581, 1465, 1276, 1244, 1198,
919, 732 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.65 (br s, 1 H), 7.25 (br s, 1 H),
6.59 (br s, 1 H), 5.55 (d, J = 6.9 Hz, 1 H), 4.23 (s, 2 H), 4.09–4.15
(m, 8 H), 2.95 (d, J = 8.7 Hz, 2 H).
13C NMR (75 MHz, CDCl3): d = 185.4, 174.2, 151.6, 147.6, 119.2,
113.1, 85.1, 80.1, 69.0, 68.5, 66.6, 65.9, 49.7, 33.3.
13C NMR (75 MHz, CDCl3): d = 195.1, 174.5, 164.3, 131.0, 128.3,
114.2, 85.5, 80.7, 69.0, 68.4, 66.9, 65.5, 55.6, 49.4, 33.9.
FAB+-MS: m/z = 404.
HRMS: m/z [M + H] calcd for C22H20FeO4: 405.0783; found:
405.0778.
FAB+-MS: m/z = 364.
6a
HRMS: m/z [M + H] calcd for C19H16FeO4: 365.0470; found:
365.0463.
Orange solid; mp 57–58 °C.
IR (KBr): 1783, 1733, 1414, 1189, 1105 cm–1.
1H NMR (300 MHz, CDCl3): d = 5.49 (d, J = 6.0 Hz, 1 H), 4.22–
4.29 (m, 11 H), 3.33–3.41 (m, 1 H), 2.84–3.02 (m, 2 H), 1.32 (t,
J = 6.9 Hz, 3 H).
10a
Orange solid; mp 139–140 °C.
IR (KBr): 3103, 1775, 1647, 1515, 1414, 1209, 1143, 724 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.75 (d, J = 4.8 Hz, 1 H), 7.60 (d,
J = 3.3 Hz, 1 H), 7.16 (br s, 1 H), 5.53 (d, J = 6.6 Hz, 1 H), 4.28 (s,
2 H), 4.05–4.18 (m, 8 H), 2.89–3.10 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 189.4, 174.1, 142.8, 135.8, 133.3,
128.6, 85.2, 80.7, 69.3, 68.6, 67.0, 65.6, 51.2, 34.0.
13C NMR (75 MHz, CDCl3): d = 174.3, 171.2, 85.2, 80.5, 69.0,
68.8, 66.5, 66.3, 61.8, 47.1, 32.6, 14.1.
FAB+-MS: m/z = 342.
HRMS: m/z [M + H] calcd for C17H18FeO4: 343.0627; found:
343.0619.
FAB+-MS: m/z = 380.
7a
HRMS: m/z [M + H] calcd for C19H16FeO3S: 381.0242; found:
381.0237.
Orange solid; mp 130–131 °C.
IR (KBr): 2248, 1781, 1415, 1183 cm–1.
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L. Shi et al.
PAPER
(7) (a) Bremeyer, N.; Smith, S. C.; Ley, S. V.; Gaunt, M. J.
Acknowledgment
Angew. Chem. Int. Ed. 2004, 43, 2681. (b) Papageorgiou,
C. D.; Cubillo de Dios, M. A.; Ley, S. V.; Gaunt, M. J.
Angew. Chem. Int. Ed. 2004, 43, 4641. (c)Papageorgiou, C.
D.; Ley, S. V.; Gaunt, M. J. Angew. Chem. Int. Ed. 2003, 42,
828. (d) Nitrogen, Oxygen and Sulfur Ylide Chemistry;
Clark, J. S., Ed.; Oxford University Press: Oxford, 2002.
(e) Li, A.-H.; Dai, L.-X.; Aggarwal, V. K. Chem. Rev. 1997,
97, 2341.
We thank the NSF-20021001, NSF-20172024 and the ‘Hundred
Scientist Program’ from the Chinese Academy of Sciences for the
financial support of this work.
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(10) Crystal Data for 2a: C21H18FeO3, MW = 374.20,
monoclinic, space group P2(1)/c, a = 21.048(3)Å,
b = 7.480(1)Å, c = 11.020(1)Å, a = 90.00°, b = 90.45(1)°,
g = 90.00°, V = 1716.19(38)Å3, Z = 4, Dc = 1.448 mg/m3,
F(000) = 776, crystal size 0.58 × 0.56 × 0.36mm, Intensity
data were collected at 291 (2) K with a Siemens P4
diffractometer with graphite monochromator, and MoKa
radiation (l = 0.71073 Å,). A total of 3371 independent
reflections were measured in range 1.96 < q < 26.00° and
2293 reflections were considered as observed applying the
condition I >2s(I). The crystal used for X-ray diffraction
was grown in a solution of acetone and petroleum ether. All
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program. The non-hydrogen atoms were refined
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anisotropically and the hydrogen atoms were included but
not refined. The final cycle of full matrix least-square
refinement was based on F2. The final R and Rw values were
0.0328 and 0.0765 respectively. Crystallographic data for
the structural analysis has been deposited with the
Cambridge Crystallographic Data Center, CCDC No.
266936 for compound 2a. Copies of this information may be
obtained free of charge from: The Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK, Fax (int. code):
+44 (1223)336 033; email:deposit@ccdc.cam.ac.uk or
http://www.ccdc.cam.ac.uk.
(11) Tables of Interatomic Distances and Configuration in
Molecules and Ions; Sutton, L. E., Ed.; The Chemical
Society: London, 1965.
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Synthesis 2005, No. 17, 2851–2856 © Thieme Stuttgart · New York