Facile synthesis of multiply substituted cyclopentadienes and conjugated dienals through reactions between 1,4-dilithio-1,3-dienes and carboxylic acid derivatives including acyl chlorides, anhydrides, and DMF

Article abstract of DOI:10.1002/ejoc.200600504

Multiply substituted cyclopentadienes were formed through reactions between phenyl-substituted 1,4-dilithio-1,3-dienes such as 1b and 1c and two molecules of acyl chlorides. The phenyl substituents on the skeletons of the dilithiobutadiene derivatives pla

Full text of DOI:10.1002/ejoc.200600504

FULL PAPER
DOI: 10.1002/ejoc.200600504
Facile Synthesis of Multiply Substituted Cyclopentadienes and Conjugated
Dienals through Reactions between 1,4-Dilithio-1,3-dienes and Carboxylic Acid
Derivatives Including Acyl Chlorides, Anhydrides, and DMF
Chao Wang,[a] Guo-Liang Mao,[a] Zhi-Hui Wang,[a] and Zhen-Feng Xi*[a,b]
Keywords: Cyclopentadienes / Dienals / 2,5-Dihydrofurans / 1,4-Dilithio-1,3-dienes / Organo-bimetallic reagents
Multiply substituted cyclopentadienes were formed through
reactions between phenyl-substituted 1,4-dilithio-1,3-dienes
such as 1b and 1c and two molecules of acyl chlorides. The
phenyl substituents on the skeletons of the dilithiobutadiene
derivatives played an essential role in the reaction pattern.
Interestingly, when anhydrides were used, normal alkyl-sub-
stituted 1,4-dilithio-1,3-dienes such as 1a could also react
similarly to the phenyl-substituted 1b and 1c, affording anal-
ogous types of multiply substituted cyclopentadienes in ex-
cellent isolated yields. Esters were found to afford mixtures
of products when treated with 1a–c. When 1,4-dilithio-1,3-
dienes were treated with DMF, multiply substituted 2,4-
diene-1,6-dials and/or 2,5-dihydrofuran derivatives were ob-
tained in good yields, depending on the substitution patterns
of the butadienyl skeletons.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
Introduction
Results and Discussion
2,4-Diene-type 1,6-bis-electrophiles such as dienals are
useful building units for the preparation of both cyclic and
linear conjugated compounds,[1–9] because these com-
pounds contain a butadienyl conjugated skeleton and one
or two terminal functional groups for potential manipula-
tion. New types of conjugated materials and functional
structures might be expected from further applications. As
part of our ongoing exploration of synthetic applications of
1,4-dilithio-1,3-butadienyl reagents,[10] we recently began to
investigate reactions between these dilithio compounds and
DMF,[11] isocyanates,[12] isothiocyanates,[13] dialkyl oxa-
lates,[14] acyl chlorides, esters, and anhydrides, expecting the
development of synthetic methods for 2,4-diene-1,6-bis-
electrophiles, which are very useful but not otherwise read-
ily available. Here we would like to report: (1) the synthesis
of multiply substituted cyclopentadienes through reactions
between 1,4-dilithio-1,3-dienes and two molecules of acyl
chlorides or anhydrides, and (2) the synthesis of multiply
substituted stereodefined cis,cis-2,4-diene-1,6-dials and/or
2,5-dihydrofuran derivatives from 1,4-dilithio-1,3-dienes
and DMF.
Reactions between 1,4-Dilithio-1,3-diene Derivatives and
Acyl Chlorides or Anhydrides, Affording Multiply
Substituted Cyclopentadienes
We have recently reported the formation of multiply sub-
stituted cyclopentadienes, cyclopentadienones, cyclopen-
tenones, and cyclopentadienyl imines through reactions be-
tween 1,4-dilithio-1,3-dienes and aldehydes and ketones,
carbon dioxide, carbon monoxide, and isocyanates, respec-
tively.[10a] From the reactions between 1,4-dilithio-1,3-
dienes 1 and acyl chlorides we expected the formation of
cis,cis-2,4-diene-1,6-diones 2 (path a, Scheme 1) and/or cy-
clopentadiene derivatives 3 or 4 (path b, Scheme 1).
[a] Beijing National Laboratory for Molecular Sciences (BNLMS),
Key Laboratory of Bioorganic Chemistry and Molecular Engi-
neering of Ministry of Education, College of Chemistry, Peking
University
Scheme 1. Potential products of reactions between 1,4-dilithio-1,3-
dienes and acyl chlorides.
Beijing 100871, China
Fax: +86-10-6275-1708
E-Mail: zfxi@pku.edu.cn
Unfortunately, though, when 1,2,3,4-tetraalkyl-substi-
tuted dilithium reagents, such as the 1,2,3,4-tetrapropyl-
substituted 1,4-dilithio-1,3-diene 1a, were used, both ali-
phatic and aromatic acyl chlorides such as MeCOCl and
PhCOCl generally gave messy reaction mixtures, probably
[b] State Key Laboratory of Organometallic Chemistry, Shanghai
Institute of Organic Chemistry, Chinese Academy of Sciences
Shanghai 200032, China
Supporting information for this article is available on the
WWW under http://www.eurjoc.org or from the author.
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due to the high reactivity of these organic substrates. Dur- Table 1. Reactions between 1,4-dilithio-1,3-dienes 1 and acyl chlo-
rides.
ing the course of our screening of substrates, however, we
found that those dilithium reagents possessing phenyl sub-
stituents on their butadienyl skeletons were capable of re-
acting cleanly with aromatic acyl chlorides, affording cyclo-
pentadiene derivatives 4 in high isolated yields, although no
formation of the expected cis,cis-2,4-diene-1,6-diones 2 and
cyclopentadiene derivatives 3 was observed (Scheme 2).
Scheme 2. Selectivity of reaction between 1 and RCOCl.
Results are listed in Table 1. It is inferred that the phenyl
groups on the butadienyl skeletons are essential for such
clean reactions, probably because the phenyl groups low-
ered the reactivity of those dilithium reagents. Changes of
solvents did not have much influence on the yields (En-
tries 2–4). The structure of 4b was determined by single-
crystal X-ray structural analysis (Figure 1, CCDC-606926).
Cyclopentadienes of this type, otherwise difficult to pre-
Figure 1. X-ray structure of 4b (CCDC-606926).
pare, might be expected to have applications as building
units for conjugated organic materials.[15,16]
In addition to acyl chlorides, we also treated these di-
lithiodienes with esters and anhydrides. The results showed
that the reactions between dilithiodienes such as 1a–c and
esters such as PhCO2Me, PhCO2Et, and AcOEt generally
afforded mixtures of products, probably because of further
reactions of the intermediates generated in situ. Interest-
ingly though, when anhydrides such as (PhCO)2O and
(PrCO)2O were used, normal alkyl-substituted 1,4-dilithio-
1,3-dienes such as 1a were also able to react smoothly, like
the phenyl-substituted 1b, to afford analogous types of mul-
tiply substituted cyclopentadienes 4 in excellent isolated
yields (Scheme 3).
Obviously, these cyclopentadiene derivatives were formed
from two molecules of the acyl chloride or anhydride; a
proposed reaction mechanism is given in Scheme 4. The
first intermediate is assumed to be monoacylated 5, which
must be stabilized through the coordination of lithium with
the carbonyl group. Cyclopentadienyl oxylithium 6, which
may be formed through intramolecular nucleophilic attack,
would then react with another molecule of ArCOCl or
(RCO)2O to afford the product 4.
Scheme 3. Reactions between 1,4-dilithio-1,3-dienes 1 and anhy-
drides.
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As we have reported in our preliminary communica-
tion,[11] however, the unexpected 2,5-dihydrofuran deriva-
tives 10 (Scheme 6) were also obtained in addition to the
expected diene-dials 7, while no formation of the other two
expected products 8 and 9 was observed. Results are given
in Table 2. Both alkyl-substituted lithium reagents 1d and
1e reacted with DMF to afford both 7 and 10, with com-
pounds 7 as the major products. Interestingly, the aryl-vinyl
dilithium reagents 1f and 1g afforded the expected dials 7c
and 7d as the sole products in 83% and 77% isolated yields,
respectively, while the trimethylsilyl-substituted lithium rea-
gents 1h or 1i and the lithium reagent 1j, with phenyl sub-
stituents, gave only the 2,5-dihydrofuran derivatives 10 in
moderate isolated yields. Scheme 6 gives a proposed reac-
tion mechanism for the formation of 2,5-dihydrofuran de-
rivatives 10 from 1,4-dilithio-1,3-dienes and DMF.
Scheme 4. A proposed mechanism.
Reactions between Lithiobutadiene Derivatives and DMF,
Affording Multiply Substituted Stereodefined Dienedials
N,N-Dimethylformamide (DMF) and other formic acid
derivatives are well known as very important carbonyl
sources for the introduction of carbon–oxygen double
bonds into target molecules:[17] reactions between DMF
and organolithium reagents, for example, have been a useful
method for the preparation of aldehydes and ketones.[18]
For reactions between 1,4-dilithio-1,3-dienes and DMF,
three types of possible routes might be expected
(Scheme 5).[11]
Table 2. Formation of 7 and/or 10 from 1 and DMF.
Scheme 5. Expected products from reactions between 1 and DMF.
Scheme 6. Proposed reaction mechanism for the formation of 10.
[a] Two isomers in 3:2 ratio. [b] Single product.
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stated otherwise. HR-MS were recorded with a ZAB-HS instru-
Treatment of 1,6-dials 7 with different organometallic
reagents efficiently afforded the corresponding 1,6-diols
13.[11] As a representative result, the preparation of 13 from
7d and lithium aluminium hydride is shown in Scheme 7.
1,6-Diols of this type have been utilized to prepare many
complex structures:[7–9] treatment of 1,6-diol 13 with PBr3,
for instance, resulted in derivative of allyl bromide 14 in
moderate isolated yield (Scheme 7). Structures such as the
dibromide 14 are important synthons, able to take part in,
for example, the formation of some seven-membered ring
systems difficult to prepare by other means.[19]
ment (1–2000u, 1000–10000, 10–10 Cug–1.)
A Typical Procedure for the Synthesis of Cyclopentadiene Deriva-
tives 4 through the Reactions between the Dilithio-1,3-dienes 1 and
Acyl Chlorides: tBuLi (4.0 mmol, 1.5  in pentane) was added at
–78 °C to a solution of the 1,4-diiodo-1,3-butadiene compound in
Et2O (10 mL, 1.0 mmol; for 4e the corresponding dibromide in
THF was used). After this reaction mixture had been stirred at
–78 °C for 1 h, the acyl chloride (2.2 mmol) was added. The reac-
tion mixture was maintained at –78 °C for 0.5 h and then at room
temperature for 0.5 h, quenched with water, and extracted with
Et2O. The extract was washed with brine and dried with MgSO4,
the solvent was then evaporated in vacuo, and the residue was then
purified by column chromatography (silica gel, dichloromethane/
hexane, 1:4) to afford the title products 4.
Compound 4a: Colorless crystals, 80% yield (447 mg). M.p. 197.4–
199.1 °C. 1H NMR (300 MHz, CDCl3, Me4Si, 25 °C): δ = –0.42 (s,
18 H, CH3), 7.46–8.07 (m, 16 H, CH), 8.17 (d, J = 8.1 Hz, 2 H,
CH), 8.65–8.70 (m, 2 H, CH) ppm. 13C NMR (75 MHz, CDCl3,
Me4Si, 25 °C): δ = –0.37 (6ϫCH3), 101.49 (1ϫquat. C), 125.30
(2ϫCH), 126.82 (1ϫCH), 126.88 (2ϫCH), 127.30 (4ϫCH),
128.40 (2ϫCH), 128.63 (2ϫCH), 129.24 (4ϫCH), 129.58
(2ϫCH), 131.45 (1ϫquat. C), 132.68 (1ϫCH), 137.27 (1ϫquat.
C), 137.44 (2ϫquat. C), 152.38 (2ϫquat. C), 157.59 (2ϫquat. C),
163.50 (1ϫquat. C) ppm. IR (neat): ν = 1730 cm–1 (C=O). HRMS
calcd. for C36H38O2Si2: 558.2410; found: 558.2411. Elemental
analysis for C36H38O2Si2 (558.86): calcd. C 77.37, H 6.85; found:
C 77.41, H 6.89.
Scheme 7. Demonstration of the usefulness of the obtained 1,6-
dials.
As well as DMF, we also treated these 1,4-dilithio-1,3-
dienes with other amides such as Me2NCOMe and Me2N-
COPh, expecting the formation of 2,4-diene-1,6-diones 2,
which are also very important compounds. However, these
reactions afforded mixtures of unknown products, along
with small amounts of monoacylated conjugated dienones.
Compound 4b: Colorless crystals, 79% yield (464 mg). M.p. 166.3–
167.8 °C. 1H NMR (300 MHz, CDCl3, Me4Si, 25 °C): δ = –0.42 (s,
18 H, CH3), 2.39 (s, 3 H, CH3), 2.46 (s, 3 H, CH3), 7.00–8.16 (m,
10 H, CH), 7.19 (d, J = 6.0 Hz, 2 H, CH), 7.33 (d, J = 6.0 Hz, 2
H, CH), 7.61 (d, J = 6.0 Hz, 2 H, CH), 8.13 (d, J = 6.0 Hz, 2 H,
CH) ppm. 13C NMR (75 MHz, CDCl3, Me4Si, 25 °C): δ = –0.32
(6ϫCH3), 21.11 (1ϫCH3), 21.69 (1ϫCH3), 101.38 (1ϫquat. C),
125.22 (2ϫCH), 126.80 (2ϫCH), 127.27 (4ϫCH), 128.84
(1ϫquat. C), 129.10 (2ϫCH), 129.28 (4ϫCH), 129.34 (2ϫCH),
129.63 (2ϫCH), 134.04 (1ϫquat. C), 136.26 (1ϫquat. C), 137.58
(2ϫquat. C), 143.23 (1ϫquat. C), 152.46 (2ϫquat. C), 157.19
(2ϫquat. C), 163.66 (1ϫquat. C) ppm. IR (neat): ν = 1729 cm–1
(C=O). HRMS calcd. for C38H42O2Si2: 586.2723; found: 586.2729.
Elemental analysis for C38H42O2Si2 (586.91): calcd. C 77.76, H
7.21; found C 77.78, H 7.11.
Conclusions
In summary, we have developed an alternative method
for the preparation of multiply substituted cyclopentadienes
through reactions between 1,4-dilithio-1,3-dienes and two
molecules of acyl chlorides or anhydrides. Cyclopentadienes
of this type, which are otherwise difficult to prepare, might
be expected to have applications as building units for conju-
gated organic materials. Depending on the substitution pat-
terns of the butadienyl skeletons, we have achieved the syn-
thesis of multiply substituted 2,4-diene-1,6-dials and/or 2,5-
dihydrofuran derivatives by treatment of 1,4-dilithio-1,3-
dienes with DMF. Under the reaction conditions used here,
mixtures of products were obtained from reactions of 1,4-
dilithio-1,3-dienes with esters such as PhCO2Me, PhCO2Et
and AcOEt and with amides other than DMF, such as
Me2NCOMe and Me2NCOPh.
CCDC-606926 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
Compound 4c: Colorless crystals, 78% yield (509 mg). M.p. 181.6–
183.2 °C. 1H NMR (300 MHz, CDCl3, Me4Si, 25 °C): δ = –0.53 (s,
18 H, CH3), 7.10–7.29 (m, 10 H, CH), 7.43–7.71 (m, 6 H, CH),
7.85–7.89 (m, 2 H, CH), 7.94 (d, J = 6.0 Hz, 1 H, CH), 8.09 (d, J
= 6.0 Hz, 1 H, CH), 8.46 (d, J = 4.0 Hz, 1 H, CH), 8.53 (d, J =
4.0 Hz, 1 H, CH), 8.81–8.88 (m, 1 H, CH), 8.96 (d, J = 4.0 Hz, 1
H, CH) ppm. 13C NMR (75 MHz, CDCl3, Me4Si, 25 °C): δ = –0.47
(6ϫCH3), 102.38 (1ϫquat. C), 124.70 (1ϫCH), 125.10 (1ϫCH),
125.23 (1ϫCH), 125.35 (1ϫCH), 125.41 (1ϫCH), 125.83
Experimental Section
General Methods: All reactions were conducted under slightly posi-
tive pressures of dry, prepurified nitrogen with use of standard
Schlenk line techniques when appropriate. Unless otherwise noted,
all starting materials were commercially available and were used (1ϫCH), 125.97 (1ϫCH), 126.28 (1ϫCH), 127.10 (4ϫCH),
without further purification. Diethyl ether and tetrahydrofuran
were heated at reflux and distilled from sodium/benzophenone ke-
tyl under nitrogen. 1,4-Dihalo-1,3-butadiene compounds were pre-
pared according to the literature.[10a] 1H and 13C NMR spectra
were recorded at 300 and 75.4 MHz, respectively, in CDCl3 unless
127.42 (4ϫCH), 127.82 (1ϫCH), 128.58 (1ϫCH), 128.85
(2ϫCH), 128.99 (1ϫCH), 129.00 (1ϫCH), 129.06 (1ϫCH),
129.24 (1ϫquat. C), 129.73 (1ϫquat. C), 131.50 (1ϫquat. C),
132.75 (1ϫCH), 133.62 (1ϫquat. C), 134.12 (1ϫquat. C), 134.22
(1ϫquat. C), 137.72 (2ϫquat. C), 150.45 (2ϫquat. C), 161.07
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Multiply Substituted Cyclopentadienes and Conjugated Dienals
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(2ϫquat. C), 163.50 (1ϫquat. C) ppm. IR (neat): ν = 1712 cm–1
(C=O). HRMS calcd. for C44H42O2Si2: 658.2723; found: 658.2726.
Elemental analysis for C44H42O2Si2 (658.97): calcd. C 80.20, H
6.42; found C 80.10, H 6.56.
1.27–1.73 (m, 12 H, CH2), 1.90–2.22 (m, 12 H, CH2) ppm. 13C
NMR (75 MHz, CDCl3, Me4Si, 25 °C): δ = 13.82 (1ϫCH3), 14.18
(1ϫCH3), 14.50 (2ϫCH3), 14.97 (1ϫCH2), 15.02 (2ϫCH3), 18.35
(1ϫCH2), 21.72 (2ϫCH2), 23.15 (2ϫCH2), 27.91 (2ϫCH2), 28.07
(2ϫCH2), 36.40 (1ϫCH2), 36.99 (1ϫCH2), 93.47 (1ϫquat. C),
137.46 (2ϫquat. C), 141.09 (2ϫquat. C), 170.49 (1ϫquat.
C) ppm. IR (neat): ν = 1746 cm–1 (C=O). HRMS calcd. for
C24H42O2: 362.3185; found: 362.3188.
Compound 4d: Colorless crystals, 62% yield (442 mg). M.p. 215.4–
216.9 °C. 1H NMR (300 MHz, CDCl3, Me4Si, 25 °C): δ = –0.34 (s,
18 H, CH3), 7.08–7.19 (m, 10 H, CH), 7.33–7.53 (m, 6 H, CH),
7.53–7.65 (m, 6 H, CH), 7.77 (d, J = 6.0 Hz, 2 H, CH), 7.83 (d, J
= 6.0 Hz, 2 H, CH), 8.34 (d, J = 6.0 Hz, 2 H, CH) ppm. 13C NMR
(75 MHz, CDCl3, Me4Si, 25 °C): δ = –0.24 (6ϫCH3), 101.48
(1ϫquat. C), 125.79 (2ϫCH), 126.90 (2ϫCH), 126.92 (2ϫCH),
127.00 (2ϫCH), 127.27 (2ϫCH), 127.32 (4ϫCH), 127.34
(4ϫCH), 127.37 (2ϫCH), 128.13 (1ϫCH), 128.80 (2ϫCH),
128.95 (2ϫCH), 129.25 (2ϫCH), 130.12 (2ϫCH), 136.41
(1ϫquat. C), 137.44 (2ϫquat. C), 139.49 (1ϫquat. C), 140.08
(1ϫquat. C), 140.63 (1ϫquat. C), 145.45 (1ϫquat. C), 152.35
(2ϫquat. C), 157.68 (2ϫquat. C), 163.44 (1ϫquat. C) ppm. IR
(neat): ν = 1728 cm–1 (C=O). HRMS calcd. for C48H46O2Si2:
710.3036; found: 710.3035. Elemental analysis for C44H42O2Si2
(711.04): calcd. C 81.08, H 6.52; found C 80.78, H 6.67.
A Typical Procedure for the Synthesis of 1,6-Dials 7 or 2,5-Dihy-
drofurans 10 through the Reactions between the Dilithio-1,3-dienes 1
and DMF: tBuLi (4.0 mmol, 1.5  in pentane) was added at –78 °C
to a solution of the 1,4-diiodo-1,3-butadiene compound (1.0 mmol)
in Et2O (10 mL). After this reaction mixture had been stirred at
–78 °C for 1 h, DMF (2.5 mmol) was added. After having been
stirred at –78 °C for a further 1 h, the reaction mixture was
quenched with saturated aqueous NaHCO3 and extracted with
Et2O. The extract was washed with water and brine and dried with
MgSO4, the solvent was then evaporated in vacuo, and the residue
was purified by column chromatography (silica gel, Et2O/hexane
1:30) to afford the product 7 or 10 as a colorless liquid.
Compound 7a: Colorless oil, 61% yield (136 mg). 1H NMR
(300 MHz, CDCl3, Me4Si, 25 °C): δ = 1.01–1.09 (m, 12 H), 2.26–
2.49 (m, 6 H), 2.66–2.79 (m, 2 H), 9.59 (s, 2 H) ppm. 13C NMR
(75 MHz, CDCl3, Me4Si, 25 °C): δ = 11.77 (2ϫCH3), 13.73
(2ϫCH3), 18.49 (2ϫCH2), 25.69 (2ϫCH2), 143.49 (2ϫquat. C),
Compound 4e: Colorless crystals, 68% yield (301 mg). M.p.169.8–
171.0 °C. H NMR (300 MHz, CDCl3, Me4Si, 25 °C): δ = 2.25 (s,
1
3 H, CH3), 2.38 (s, 3 H, CH3), 7.03 (s, 2 H, CH), 6.98–7.49 (m, 14
H, CH), 7.62 (d, J = 6.0 Hz, 2 H, CH), 7.01 (d, J = 4.0 Hz, 2 H,
CH) ppm. 13C NMR (75 MHz, CDCl3, Me4Si, 25 °C): δ = 21.03
(1ϫCH3), 21.65 (1ϫCH3), 90.01 (1ϫquat. C), 124.44 (2ϫCH),
125.60 (4ϫCH), 126.77 (2ϫCH), 127.18 (2ϫCH), 127.79
(1ϫquat. C), 128.29 (4ϫCH), 129.20 (2ϫCH), 129.54 (2ϫCH),
129.72 (2ϫCH), 132.75 (1ϫquat. C), 134.21 (1ϫquat. C), 136.95
(1ϫquat. C), 143.66 (2ϫquat. C), 151.37 (2ϫquat. C), 162.84
(1ϫquat. C) ppm. IR (neat): ν = 1731 cm–1 (C=O). HRMS calcd.
for C32H26O2: 442.1933; found: 442.1930. Elemental analysis for
C32H26O2 (442.55): calcd. C 86.85, H 5.92; found C 86.73, H 5.97.
157.36 (2ϫquat. C), 192.33 (2ϫCH) ppm. IR (neat):
ν =
1673 cm–1 (C=O). HRMS calcd. for C14H22O2: 222.1620; found:
222.1611.
Compound 7b: Colorless oil, 44% yield (111 mg). 1H NMR
(300 MHz, CDCl3, Me4Si, 25 °C): δ = 0.94 (t, J = 7.2 Hz, 6 H),
1.27–1.50 (m, 4 H), 1.65–1.80 (m, 2 H), 2.00–2.39 (m, 8 H), 3.00–
3.08 (m, 2 H), 9.61 (s, 2 H) ppm. 13C NMR (75 MHz, CDCl3,
Me4Si, 25 °C): δ = 14.29 (2ϫCH3), 22.72 (2ϫCH2), 26.98
(2ϫCH2), 28.50 (2ϫCH2), 35.29 (2ϫCH2), 139.94 (2ϫquat. C),
A Typical Procedure for the Synthesis of Cyclopentadiene Deriva-
tives 4 through the Reactions between the Dilithio-1,3-dienes 1 and
Acyl Anhydrides: tBuLi (4.0 mmol, 1.5  in pentane) was added at
–78 °C to a solution of the 1,4-diiodo-1,3-butadiene compound in
Et2O (10 mL, 1.0 mmol). This reaction mixture was stirred at
–78 °C for 1 h and HMPA (4.4 mmol) was then added. After
20 min, the acid anhydride (2.1 mmol) was added, and the reaction
mixture was allowed to warm to room temperature and kept for
1 h. The above reaction mixture was quenched with water and ex-
tracted with Et2O, the extract was washed with brine and dried
with MgSO4, the solvent was then evaporated in vacuo, and the
residue was then purified by column chromatography (silica gel,
dichloromethane/hexane, 1:4) to afford the title products 4.
158.09 (2ϫquat. C), 191.56 (2ϫCH) ppm. IR (neat):
ν =
1673 cm–1 (C=O). HRMS calcd. for C16H24O2: 248.1776; found:
248.1784.
Compound 7c: Colorless oil, 83% yield (180 mg). 1H NMR
(300 MHz, CDCl3, Me4Si, 25 °C): δ = 1.00 (t, J = 7.5 Hz, 3 H),
1.11 (t, J = 7.5 Hz, 3 H), 2.36–2.61 (m, 3 H), 2.76–2.92 (m, 1 H),
7.17–7.25 (m, 1 H), 7.50–7.66 (m, 2 H), 7.95–8.02 (m, 1 H), 9.23
(s, 1 H), 10.05 (s, 1 H) ppm. 13C NMR (75 MHz, CDCl3, Me4Si,
25 °C): δ = 11.85 (1ϫCH3), 13.71 (1ϫCH3), 18.30 (1ϫCH2),
29.75 (1ϫCH2), 128.56 (1ϫCH), 130.24 (1ϫCH), 130.80
(1ϫCH), 133.52 (1ϫCH), 134.17 (1ϫquat. C), 141.37 (1ϫquat.
C), 141.44 (1ϫquat. C), 159.83 (1ϫquat. C), 190.98 (1ϫCH),
192.61 (1ϫCH) ppm. IR (neat): ν = 1673 cm–1, 1698 cm–1 (C=O).
HRMS calcd. for C14H16O2: 216.1150; found: 216.1171.
Compound 4a: 88% yield (506 mg).
Compound 4f: Colorless oil, 83% yield (358 mg). 1H NMR
(300 MHz, CDCl3, Me4Si, 25 °C): δ = 0.66 (t, J = 7.2 Hz, 6 H,
CH3), 1.00 (t, J = 7.5 Hz, 6 H, CH3), 1.48–1.61 (m, 2 H, CH2),
1.83–2.04 (m, 2 H, CH2), 2.19–2.32 (m, 2 H, CH2), 7.20–7.60 (m, 3
H, CH), 8.13–8.16 (m, 2 H, CH) ppm. 13C NMR (75 MHz, CDCl3,
Me4Si, 25 °C): δ = 14.73 (2ϫCH3), 14.96 (2ϫCH3), 21.86
(2ϫCH2), 23.30 (2ϫCH2), 28.33 (4ϫCH2), 95.00 (1ϫquat. C),
125.21 (2ϫCH), 126.95 (1ϫCH), 128.43 (2ϫCH), 128.67
(2ϫCH), 129.76 (2ϫCH), 131.70 (1ϫquat. C), 132.76 (1ϫCH),
139.48 (1ϫquat. C), 142.04 (2ϫquat. C), 142.61 (2ϫquat. C),
163.36 (1ϫquat. C) ppm. IR (neat): ν = 1733 cm–1 (C=O). HRMS
calcd. for C30H38O2: 430.2872; found: 430.2870.
Compound 7d: Colorless oil, 77% yield (188 mg). 1H NMR
(300 MHz, CDCl3, Me4Si, 25 °C): δ = 0.94 (t, J = 7.5 Hz, 3 H),
1.01 (t, J = 7.5 Hz, 3 H), 1.24–1.60 (m, 4 H), 2.28–2.59 (m, 3 H),
2.70–2.85 (m, 1 H), 7.14–7.24 (m, 1 H), 7.46–7.68 (m, 2 H), 7.93–
8.03 (m, 1 H), 9.25 (s, 1 H), 10.06 (s, 1 H) ppm. 13C NMR
(75 MHz, CDCl3, Me4Si, 25 °C): δ = 14.20 (1ϫCH3), 14.36
(1ϫCH3), 20.82 (1ϫCH2), 22.45 (1ϫCH2), 27.12 (1ϫCH2), 39.05
(1ϫCH2), 128.53 (1ϫCH), 130.19 (1ϫCH), 130.82 (1ϫCH),
133.48 (1ϫCH), 134.02 (1ϫquat. C), 140.37 (1ϫquat. C), 141.86
(1ϫquat. C), 158.92 (1ϫquat. C), 190.98 (1ϫCH), 192.83
(1ϫCH) ppm. IR (neat): ν = 1673 cm–1, 1698 cm–1 (C=O). HRMS
calcd. for C16H20O2: 244.1463; found: 244.1475.
Compound 4g: Colorless oil, 78% yield (284 mg). 1H NMR
Compound 10a: Colorless oil, 10% yield (28 mg, two isomers in 3:2
(300 MHz, CDCl3, Me4Si, 25 °C): δ = 0.81–0.96 (m, 18 H, CH3), ratio). 1H NMR (300 MHz, CDCl3, Me4Si, 25 °C): δ = 065–1.19
Eur. J. Org. Chem. 2007, 1267–1273
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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C. Wang, G.-L. Mao, Z.-H. Wang, Z.-F. Xi
(s, 12 H), 1.46–1.99 (m, 6 H), 2.01–2.13 (m, 2 H), 2.29 (s, 3.6 H), Synthesis of 1,6-Diols 13 by Treatment of Compounds 7 with Orga-
FULL PAPER
2.31 (s, 2.4 H), 5.28 (s, 0.6 H), 5.37 (s, 0.4 H), 9.55 (d, J = 4.6 Hz,
0.4 H), 9.68 (d, J = 4.0 Hz, 0.6 H) ppm. 13C NMR (75 MHz,
CDCl3, Me4Si, 25 °C): δ = 7.50 (1ϫCH3), 8.29 (1ϫCH3), 12.49
(1ϫCH3), 12.54 (1ϫCH3), 12.59 (1ϫCH3), 12.82 (1ϫCH3), 13.59
(1ϫCH3), 13.92 (1ϫCH3), 17.65 (1ϫCH2), 17.70 (1ϫCH2), 18.28
(1ϫCH2), 18.38 (1ϫCH2), 18.58 (1ϫCH2), 18.63 (1ϫCH2), 29.14
(1ϫCH2), 29.85 (1ϫCH2), 39.52 (1ϫCH3), 39.61 (2ϫCH3), 61.51
(1ϫCH), 62.06 (1ϫCH), 91.34 (1ϫquat. C), 91.41 (1ϫquat. C),
101.22 (1ϫquat. C), 101.72 (1ϫquat. C), 136.33 (1ϫquat. C),
136.78 (1ϫquat. C), 138.93 (1ϫquat. C), 140.49 (1ϫquat. C),
204.44 (1ϫCH), 204.49 (1ϫCH) ppm. HRMS calcd. for
C16H29NO2: 267.2198; found: 267.2196.
nometallic Reagents: LiAlH4 (0.5 mmol) was added at –10 °C to a
solution of 7 (1.0 mmol) in Et2O (10 mL). After having been stirred
at the same temperature for 1 h, this reaction mixture was
quenched with H2SO4 (6 ) and then extracted with Et2O. The ex-
tract was washed with water and brine and dried with Na2SO4, the
solvent was then evaporated in vacuo, and the residue was purified
by column chromatography (silica gel, Et2O/hexane 1:3) to afford
the product 13 as a colorless solid, 93% yield (231 mg). M.p. 69–
1
70 °C. H NMR (300 MHz, CDCl3, Me4Si, 25 °C): δ = 0.85 (t, J
= 7.2 Hz, 3 H), 0.97 (t, J = 7.2 Hz, 3 H), 1.11–1.38 (m, 2 H), 1.41–
1.62 (m, 2 H), 2.03–2.40 (m, 4 H), 3.58 (s, 2 H), 4.10 (br., 1 H),
4.19–4.52 (m, 2 H), 4.73 (br., 1 H), 6.76–6.99 (m, 1 H), 7.08–7.26
(m, 2 H), 7.28–7.50 (m, 1 H) ppm. 13C NMR (75 MHz, CDCl3,
Me4Si, 25 °C): δ = 14.23 (1ϫCH3), 14.26 (1ϫCH3), 20.87
(1ϫCH2), 22.09 (1ϫCH2), 31.69 (1ϫCH2), 36.61 (1ϫCH2), 61.83
(1ϫCH2), 62.13 (1ϫCH2), 126.80 (1ϫCH), 127.32 (1ϫCH),
129.19 (1ϫCH), 129.86 (1ϫCH), 136.59 (1ϫquat. C), 137.94
(1ϫquat. C), 138.01 (1ϫquat. C), 141.68 (1ϫquat. C) ppm.
HRMS calcd. for [C16H24O2Na]+: 271.1668; found: 271.1667.
Compound 10b: Colorless oil, 32% yield (91 mg). 1H NMR
(300 MHz, CDCl3, Me4Si, 25 °C): δ = 0.84 (t, J = 7.5 Hz, 3 H),
0.92 (t, J = 7.5 Hz, 3 H), 1.10–1.76 (m, 10 H), 1.78–2.05 (m, 5 H),
2.20–2.29 (m, 1 H), 2.29 (s, 6 H), 2.44–2.60 (m, 1 H), 5.31 (s, 1
H),9.38 (d, J = 4.8 Hz, 1 H) ppm. 13C NMR (75 MHz, CDCl3,
Me4Si, 25 °C): δ = 14.03 (1ϫCH3), 14.19 (1ϫCH3), 20.98
(1ϫCH2), 21.31 (1ϫCH2), 23.26 (1ϫCH2), 24.06 (1ϫCH2), 26.37
(1ϫCH2), 26.77 (1ϫCH2), 26.92 (1ϫCH2), 35.75 (1ϫCH2), 39.40
(2ϫCH3), 55.66 (1ϫCH), 87.69 (1ϫquat. C), 102.84 (1ϫquat.
C), 129.54 (1ϫquat. C), 139.42 (1ϫquat. C), 205.04
(1ϫCH) ppm.
Synthesis of Dibromide 14 from 13 and Phosphorus Tribromide:
Phosphorus tribromide (2.0 mmol) was added at –10 °C to a solu-
tion of 13 (1.0 mmol) in Et2O (10 mL). After having been stirred
at the same temperature for 1 h, this reaction mixture was
quenched with water and extracted with hexane. The extract was
dried with Na2SO4 after having been washed in turn with saturated
aqueous NaHCO3, water, and brine. The solvent was then evapo-
rated in vacuo and the residue was purified by column chromatog-
raphy (silica gel, hexane) to afford the product 14 as a colorless oil,
Compound 10c: Colorless oil, 39% yield (128 mg). 1H NMR
(300 MHz, CDCl3, 25 °C): δ = 0.00 (s, 9 H), 0.05 (s, 9 H), 1.17 (s,
3 H), 1.51 (s, 3 H), 2.11 (s, 6 H), 5.34 (s, 1 H), 9.10 (d, J = 6.3 Hz,
1
H) ppm. 13C NMR (75 MHz, CDCl3, 25 °C):
δ = –0.65
(3ϫCH3), 0.00 (3ϫCH3), 12.35 (1ϫCH3), 26.37 (1ϫCH3), 39.67
(2ϫCH3), 57.49 (1ϫCH), 90.11 (1ϫquat. C), 106.10 (1ϫquat.
C), 131.24 (1ϫquat. C), 153.58 (1ϫquat. C), 204.13
(1ϫCH) ppm. IR (neat): ν = 1699 cm–1 (C=O). HRMS calcd. for
C16H33NO2Si2: 327.2050; found: 327.2043.
1
55% yield (206 mg). H NMR (300 MHz, CDCl3, Me4Si, 25 °C): δ
= 0.90 (t, J = 7.5 Hz, 3 H), 1.03 (t, J = 7.5 Hz, 3 H), 1.20–1.71 (m,
4 H), 2.02–2.20 (m, 1 H), 2.26–2.62 (m, 3 H), 3.59–3.85 (m, 2 H),
4.42 (s, 1 H), 6.91–7.59 (m, 4 H) ppm. 13C NMR (75 MHz, CDCl3,
Me4Si, 25 °C): δ = 14.12 (1ϫCH3), 14.23 (1ϫCH3), 21.10
(1ϫCH2), 21.86 (1ϫCH2), 31.48 (1ϫCH2), 31.57 (1ϫCH2), 35.95
(1ϫCH2), 36.18 (1ϫCH2), 127.87 (1ϫCH), 128.36 (1ϫCH),
129.05 (1ϫCH), 130.99 (1ϫCH), 134.39 (1ϫquat. C), 134.64
(1ϫquat. C), 140.47 (1ϫquat. C), 141.20 (1ϫquat. C). HRMS
calcd. for C16H22Br2: 372.0088; found: 372.0090.
Compound 10d: Colorless oil, 45% yield (208 mg). 1H NMR
(300 MHz, CDCl3, 25 °C): δ = 0.00 (s, 18 H), 0.66–0.78 (m, 7 H),
0.99–1.29 (m, 15 H), 1.49–1.72 (m, 4 H), 2.10 (s, 6 H), 2.30–2.50
(m, 1 H), 5.32 (s, 1 H), 9.70–9.74 (m, 1 H) ppm. 13C NMR
(75 MHz, CDCl3, 25 °C): δ = 0.00 (6ϫCH3), 14.74 (1ϫCH3),
14.79 (1ϫCH3), 23.31 (1ϫCH2), 23.35 (1ϫCH2), 24.12 (1ϫCH2),
27.92 (1ϫCH2), 30.01 (1ϫCH2), 30.82 (1ϫCH2), 31.99 (1ϫCH2),
32.27 (1ϫCH2), 32.55 (1ϫCH2) 39.46 (1ϫCH2), 40.34 (2ϫCH3),
53.16 (1ϫCH), 91.54 (1ϫquat. C), 107.71 (1ϫquat. C), 134.11
(1ϫquat. C), 156.13 (1ϫquat. C), 203.78 (1ϫCH) ppm. IR (neat):
ν = 1723 cm–1 (C=O).
Supporting Information (see also the footnote on the first page of
1
this article): Copies of H NMR and 13C NMR spectra of all new
compounds.
Acknowledgments
Compound 10e: Colorless oil, 55% (185 mg, two isomers in 3:2 ra-
tio). H NMR (300 MHz, CDCl3, Me4Si, 25 °C): δ = 1.11 (d, J =
This work was supported by the National Science Fund for Distin-
guished Young Scholars (29825105), the Major State Basic Re-
search Development Program (G2000077502-D), and the National
Natural Science Foundation of China. The Cheung Kong Scholars
Programme, the Qiu Shi Science & Technologies Foundation, Eli
Lilly and Company, and BASF are gratefully acknowledged.
1
7.2 Hz, 1.3 H), 1.17 (d, J = 7.2 Hz, 1.7 H), 1.60 (s, 1.7 H), 1.61 (s,
1.3 H), 2.37 (s, 3.6 H), 2.38 (s, 2.4 H), 2.43–2.52 (m, 1 H), 5.91 (s,
0.6 H), 6.03 (s, 0.4 H), 6.99–7.36 (m, 10 H), 9.63 (d, J = 2.7 Hz,
0.6 H), 9.82 (d, J = 3.9 Hz, 0.4 H) ppm. 13C NMR (75 MHz,
CDCl3, Me4Si, 25 °C): δ = 9.34 (1ϫCH3), 9.58 (1ϫCH3), 24.65
(1ϫCH3), 25.71 (1ϫCH3), 39.26 (2ϫCH3), 39.27 (2ϫCH3), 53.81
(1ϫCH), 54.18 (1ϫCH), 89.82 (1ϫquat. C), 90.06 (1ϫquat. C),
102.15 (1ϫquat. C), 103.02 (1ϫquat. C), 127.47 (1ϫCH), 127.49
(1ϫCH), 127.87 (1ϫCH), 127.89 (1ϫCH), 127.97 (1ϫCH),
128.02 (1ϫCH), 128.59 (1ϫCH), 128.60 (1ϫCH), 128.71
(1ϫCH), 128.72 (1ϫCH), 128.96 (1ϫCH), 129.39 (1ϫCH),
132.93 (1ϫCH2), 133.09 (1ϫCH2), 134.50 (1ϫquat. C), 134.60
(1ϫquat. C), 135.55 (1ϫquat. C), 136.17 (1ϫquat. C), 142.23
(1ϫquat. C), 143.12 (1ϫquat. C), 204.51 (1ϫCH), 205.47
(1ϫCH) ppm. IR (neat): ν = 1720 cm–1 (C=O). HRMS calcd. for
C22H25NO2: 335.1885; found: 335.1870.
[1] a) H. S. P. Rao, S. Jothilingam, J. Org. Chem. 2003, 68, 5392–
5394; b) H. S. P. Rao, S. Jothilingam, Tetrahedron Lett. 2001,
42, 6595–6597; c) S. Onitsuka, H. Nishino, K. Kurusawa, Tet-
rahedron Lett. 2000, 41, 3149–3152; d) J. Bach, R. Berenguer,
J. Garcia, M. Lopez, J. Manzanal, J. Vilarrasa, Tetrahedron
1998, 54, 14947–14962.
[2] a) X. Y. Lu, C. M. Zhang, Z. R. Xu, Acc. Chem. Res. 2001, 34,
535–544; b) X. Y. Lu, Chin. J. Org. Chem. 2001, 21, 769–783;
c) C. Bee, E. Leclerc, M. A. Tius, Org. Lett. 2003, 5, 4927–
4930; d) M. Iqbal, P. Evans, Tetrahedron Lett. 2003, 44, 5741–
5745; e) D. J. Kerr, C. Metje, B. L. Flynn, Chem. Commun.
1272
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 1267–1273

Multiply Substituted Cyclopentadienes and Conjugated Dienals
FULL PAPER
2003, 1380–1381; f) U. Kazmaier, Tetrahedron 1998, 54, 1491–
1496; g) U. Kazmaier, Chem. Commun. 1997, 2305–2306; h) F.
Rezgui, M. M. ElGaied, Tetrahedron 1997, 53, 15711–15716; i)
G. Majetch, S. Liu, J. Fang, D. Siesel, Y. Zhang, J. Org. Chem.
1997, 62, 6928–6951; j) S. J. Brocchini, R. G. Lawton, Tetrahe-
dron Lett. 1997, 38, 6319–6322.
[9] a) M. Bols, T. Skrydstrup, Chem. Rev. 1995, 95, 1253–1277; b)
G. Stork, G. Kim, J. Am. Chem. Soc. 1992, 114, 1087–1088; c)
G. Stork, T. T. Chan, G. A. Breault, J. Am. Chem. Soc. 1992,
114, 7578–7579; d) S. M. Sieburth, L. Fensterbank, J. Org.
Chem. 1992, 57, 5279–5281.
[10] a) Z. Xi, Eur. J. Org. Chem. 2004, 2773–2781. and references
cited therein; see also; b) F. Foubelo, M. Yus, Curr. Org. Chem.
2005, 9, 459–490; c) J. A. Varela, C. Saa, Chem. Rev. 2003, 103,
3787–3801.
[3] a) J. G. Walsh, P. F. Furlong, D. G. Gilheany, J. Chem. Soc.,
Chem. Commun. 1994, 67–68; b) J. G. Walsh, P. F. Furlong,
D. G. Gilheany, J. Chem. Soc., Perkin Trans. 1 1999, 3657–
3665. and references cited therein.
[11] G. Mao, C. Wang, J. Chen, A. Muramatsu, Z. Xi, Tetrahedron
Lett. 2005, 46, 5369–5372.
[4] P. Langer, W. Freiberg, Chem. Rev. 2004, 104, 4125–4149.
[5] X. Zeng, M. Qian, Q. Hu, E. Negishi, Angew. Chem. Int. Ed.
2004, 43, 2259–2263.
[12] C. Wang, J. Lu, G. Mao, Z. Xi, J. Org. Chem. 2005, 70, 5150–
5156.
[6] A. Kasatkin, R. J. Whitby, J. Am. Chem. Soc. 1999, 121, 7039–
[13] C. Wang, Q. Song, Z. Xi, Tetrahedron 2004, 60, 5207–5214.
[14] G. Mao, J. Lu, Z. Xi, Tetrahedron Lett. 2004, 45, 8095–8098.
[15] a) Z. Xi, Top. Catal. 2005, 35, 63–71; b) M. Enders, R. W.
Baker, Curr. Org. Chem. 2006, 10, 937–953.
7049.
[7] a) P. V. Ramachandran, M. T. Rudd, M. V. R. Reddy, Tetrahe-
dron Lett. 2005, 46, 2547–2549; b) M. E. Martin, D. Planch-
enault, F. Huet, Tetrahedron 1995, 51, 4985–4990; c) J. H.
[16] Z. Wang, H. Fan, Z. Xi, Tetrahedron 2006, 62, 6967–6972.
Rigby, H. S. Ateeq, N. R. Charles, S. V. Cuisiat, M. D. Fergu- [17] T. Morimoto, K. Kakiuchi, Angew. Chem. Int. Ed. 2004, 43,
son, J. A. Henshilwood, C. Krueger, C. O. Ogbu, K. M. Short,
M. J. Heeg, J. Am. Chem. Soc. 1993, 115, 1382–1396.
5580–5588.
[18] B. J. Wakefield, Organolithium Methods, Academic Press, Lon-
don, 1988, pp. 82–88.
[19] a) G. Molander, Acc. Chem. Res. 1998, 31, 603–609; b) G. Illu-
minati, L. Mandolini, Acc. Chem. Res. 1981, 14, 95–102.
Received: June 10, 2006
[8] a) F. Foubelo, S. A. Saleh, M. Yus, J. Org. Chem. 2000, 65,
3478–3483; b) Y. Huang, X. Mo, Tetrahedron Lett. 1995, 36,
3539–3542; c) J. E. Hill, G. Balaich, P. E. Fanwick, I. P.
Rothwell, Organometallics 1993, 12, 2911–2924; d) H. J. Reich,
S. K. Shah, F. Chow, J. Am. Chem. Soc. 1979, 101, 6648–6656.
Published Online: January 8, 2007
Eur. J. Org. Chem. 2007, 1267–1273
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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