Reaction of 4-methyl, 4-phenyl, and 4-hydrogen substituted 1-lithio-1,3-butadienes with aldehydes: preparation of multiply substituted cyclopentadienes

Article abstract of DOI:10.1016/j.tet.2006.04.083

Reaction of aldehydes with 1-lithio-1,3-butadiene reagents possessing a methyl substituent, a phenyl substituent or a hydrogen at position 4 of the butadienyl skeletons was studied. Polysubstituted cyclopentadiene derivatives were obtained in high yields

Full text of DOI:10.1016/j.tet.2006.04.083

Tetrahedron 62 (2006) 6967–6972
Reaction of 4-methyl, 4-phenyl, and 4-hydrogen substituted
1-lithio-1,3-butadienes with aldehydes: preparation
of multiply substituted cyclopentadienes
Zhihui Wang,a Hongyun Fanga and Zhenfeng Xia,b,
*
aBeijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular
Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
bState Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry,
Chinese Academy of Sciences, Shanghai 200032, China
Received 22 March 2006; revised 21 April 2006; accepted 21 April 2006
Available online 12 May 2006
Abstract—Reaction of aldehydes with 1-lithio-1,3-butadiene reagents possessing a methyl substituent, a phenyl substituent or a hydrogen at
position 4 of the butadienyl skeletons was studied. Polysubstituted cyclopentadiene derivatives were obtained in high yields upon hydrolysis
using strong acidic solution. Reaction mechanism study revealed that these cyclopentadienes were formed via an acid-promoted cyclization of
conjugated dienols. Thus, stereodefined all-cis substituted dienols or a wide diversity of substituted cyclopentadienes can be obtained from the
same 1-lithio-1,3-butadiene reagent and aldehyde by adjusting the hydrolysis conditions.
Ó 2006 Elsevier Ltd. All rights reserved.
1. Introduction
the preparation of useful cyclopentadiene derivatives8 and
conjugated butadienols.9,10
We have recently demonstrated that 1-lithio-1,3-butadienes
I–IV (Fig. 1) are useful reagents for the preparation of a
wide variety of linear and cyclic compounds through their
direct addition onto nitriles,1 CO,2 CO2,3 aldehydes, and
ketones.4,5 Results have shown that the substitution patterns
at position 4 of 1-lithio-1,3-butadienes I (alkenyl lith-
ium),1–4 II (silyl group),6 III (naphthyl group),7 and IV
(hydrogen)1–4 have remarkable influences on the reactivity
of these organolithium reagents. In the case of 1-lithio-
1,3-butadienes IV (hydrogen), their reaction with aldehydes
afforded stereodefined all-cis substituted dienols or multiply
substituted cyclopentadienes depending on the nature of
substituents and work up procedures.4c Prompted by the dif-
ferent types of results obtained from 1-lithio-1,3-butadienes
I–IV, we prepared 1-lithio-1,3-butadiene reagent V and VI
possessing a methyl substituent and a phenyl substituent at
position 4 of the butadienyl skeletons, respectively, expect-
ing new reaction patterns and synthetically useful methodol-
ogy. We found that reactions of these organolithium reagents
with aldehydes afforded fully substituted cyclopentadienes,
via the acid-promoted cyclization of conjugated dienols.
This type of reaction provides an alternative method for
Li
SiMe3
Li
Li
Li
Naph
II
I
III
Li
H
Li
Me
Li
Ph
IV
V
VI
Figure 1. A variety of 1-lithio-1,3-butadienes of different substitution
patterns at position 4.
2. Results and discussion
1-Bromo-4-methyl-1,2,3,4-tetraethyl-1,3-butadiene 2a was
successfully obtained in 67% isolated yield via selective lith-
iation of 1a followed by treatment with Me2SO4 (Eq. 1).11
Bromotriene 2b was prepared similarly via selective lithiation
of 1a followed by treatment with LTMP and 1,2-epoxy-
octane.12 1-Iodo-4-phenyl-1,2,3,4-tetraethyl-1,3-butadiene
2c and 1-iodo-1,3-butadienes 2d–g were conveniently
prepared according to known procedures.13,14 These halo-
butadienes and halotrienes are interesting and useful
* Corresponding author. Tel.: +86 10 6275 9728; fax: +86 10 6275 1708;
e-mail: zfxi@pku.edu.cn
0040–4020/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2006.04.083

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Z. Wang et al. / Tetrahedron 62 (2006) 6967–6972
Table 1. Formation of cyclopentadiene derivatives by acidic quenching of
the reaction mixture of Va, VIa, and VIIa with aldehydesa
compounds but have not been much utilized in organic
synthesis.
Lithiobutadiene
reagent
Aldehyde
Product 3
Yield of
3 (%)b
Et
Et
Et
Et
Et
Et
1) 2 t-BuLi
2) Me2SO4
Et
Ph
I
Br
Me
Br
Et
Et
(1)
Et
Et
Me
Va
Li
C
3a
PhCHO
74
Me
Et
1a
Et
2a
Et
Et
Et
67% isolated yield
Ph-Ph-4
Et
Et
R
R
Et
Et
Et
3b
3c
3d
C
Et
Et
Et
Va
4-Ph–PhCHO
PrCHO
54
56
H
I
Hex
Ph
I
Me
Br
Et
Pr
R
Et
R
Et
2b
Et
2c
Et
Et
2d: R = Me
2e: R = Et
2f : R = Pr
2g: R = Bu
Et
C
Va
Me
Et
Et
Ph
Lithiation of 2a with 2 equiv of t-BuLi afforded 1-lithio-4-
methyl-1,2,3,4-tetraethyl-1,3-butadiene Va quantitatively
(Eq. 2). Reaction of thus generated Va with benzaldehyde
went smoothly. However, quenching the reaction mixture
with 3 N HCl resulted in two products, which were deter-
mined to be the corresponding butadienyl alcohol and a
cyclopentadiene derivative. Because the cyclopentadiene
derivative might be formed via the known acid-catalyzed
cyclization of butadienyl alcohols,4c,15 we decided to treat
the reaction mixture with strong aqueous acidic solution
(12 N HCl). Fully substituted cyclopentadiene 3a was ob-
tained as the sole product in 74% isolated yield. Results
are given in Table 1. Both aromatic and aliphatic aldehydes
could be applied for this reaction to afford the fully
substituted cyclopentadienes in good isolated yields. This
type of cyclopentadienes, which are otherwise difficult to
prepare, can be expected to have applications as building
units for conjugated organic materials. Reaction of the con-
jugated triene VIIa with benzaldehyde generated the cyclo-
pentadiene derivative 3g in a low yield, probably due to the
competitive intramolecular carbo-lithiation of VIIa. The
structure of product 3e was determined by single-crystal
X-ray structural analysis (Fig. 2).16
Et
Et
Et
Et
Ph
VIa
Li
C
PhCHO
65
Ph
Et
Et
Et
Ph-Ph-4
Et
Et
Et
C
3e
VIa
4-Ph–PhCHO
PrCHO
77
62
Ph
Et
Pr
Et
Et
Et
C
3f
VIa
Ph
Et
Et
Et
Ph
Et
Et
Et
Hex
VIIa
3g
C
PhCHO
26
Li
Et
Hex
Et
Et
a
Reaction conditions are given in Eq. 2.
Isolated yields.
b
Figure 2. X-ray structure of 3e.

Z. Wang et al. / Tetrahedron 62 (2006) 6967–6972
6969
Table 2. Formation of cyclopentadiene derivatives and dienols by acidic
quenching of the reaction mixture of IV with aldehydesa
Et
Et
Et
Et
Et
Et
Et
Et
1) 2 t-BuLi
R
X
R
Li
Run
Reagent IV
Aldehyde
Hydrolysis Product Yield
condition
-78 °C, 1h
5 or 6
(%)b
Me
2a: R = Me, X = Br
Va: R = Me
2c: R = Ph, X = I
VIa: R = Ph
Me
Li
IVa
1
4-OMePhCHO 3 N HCl
5a
(53)
(2)
Me
R'
Et
2) 1.2 R'CHO
-78 °C, 1h
3) 12 N HCl
Me
Et
Et
Et
R
Et
Et
Et
Li
IVb
2
PhCHO
3 N HCl
5bc
(75)
3
Et
As discussed above, these cyclopentadienes might be gener-
ated via the acid-catalyzed cyclization of their corresponding
butadienyl alcohols.4c,15 In fact, when the reaction mixture of
VIa with 4-phenylbenzaldehyde was quenched with aqueous
NaHCO3 instead of acidic solution, an alcohol 4a was ob-
tained in 72% isolated yield (Eq. 3). Treatment of the isolated
pure butadienyl alcohol 4a with 12 N HCl afforded the cyclo-
pentadiene derivative 3e in 77% isolated yield.
3
4
5
IVb
IVb
IVb
Pr
2-FurylCHO 3 N HCl
4-BrPhCHO 3 N HCl
2-ThienylCHO 3 N HCl
5cc
5dd
5ee
(71)
(86)
(78)
Pr
Pr
Li
Satd aq
PhCHO
IVc
6
6a
99 (95)
NaHCO3
Pr
7
8
9
IVc
IVc
PhCHO
PrCHO
PrCHO
3 N HCl
Satd aq
NaHCO3
3 N HCl
5ff
6b
5gg
99 (86)
82 (65)
85 (70)
1) 2 t-BuLi
Et
Et
Et
Et
Li
°
-78 C, 1h
I
IVc
Bu
Et
Et
2c
Et
Et
VIa
Bu
Bu
2) 1.2 equiv.
CHO
Li
IVd
(3)
10
4-OMePhCHO 3 N HCl
5h
(81)
Ph
Et
Et
Bu
- 78 °C, 1h
3) aq. NaHCO3
a
C
Ph
Reaction conditions: shown in Eq. 4.
GC yields. Isolated yields are given in parentheses.
Two isomers in 3:1.
Three isomers in 1:1:1.
Three isomers in 2:1:1.
b
c
d
e
f
Et
Et OH
4a: 72% isolated yield
Similarly, conjugated dienols or cyclopentadiene derivatives
could be prepared highly selectively in excellent yields by
hydrolysis of the reaction mixtures of 1-lithiobutadienes IV
(a hydrogen substituent at position 4) with aldehydes (Eq.
4). Results are given in Table 2. As indicated by the hydroly-
sis conditions shown in Table 1 and Table 2, when there was
substituent such as a methyl group (V) or a phenyl group (VI)
at position 4 of the butadienyl skeletons, stronger acid (12 N
HCl) was required for the formation of cyclopentadiene deriv-
atives from their corresponding dienols. In the cases of 6a
(run 6 of Table 2) and 6b (run 8 of Table 2) without substitu-
ents at position 4, weaker acid (3 N HCl) was good enough to
promote the cyclization. These isolated dienols 6a and 6b
could be quantitatively transformed to their corresponding
cyclopentadiene derivatives when treated with 3 N HCl.
Two isomers in 5:2.
Two isomers in 4:3.
g
3. Conclusions
We have investigated the preparation and reaction of the use-
ful 1-lithio-1,3-butadiene reagents possessing a phenyl sub-
stituent, a methyl substituent, and a hydrogen at position 4 of
the butadienyl skeletons. Results of these organolithium re-
agents with aldehydes show that they are versatile synthetic
building units. Cyclopentadiene derivatives thus formed are
expected to have useful applications for conjugated organic
materials’ synthesis.
R
R
R
R
R
R
1) 2 t-BuLi
H
I
H
Li
°
-78 C, 1h
4. Experimental
R
R
2d: R = Me
2e: R = Et
2f: R = Pr
2g: R = Bu
4.1. General methods
IVa: R = Me
IVb: R = Et
IVc: R = Pr
IVd: R = BuI
All reactions were conducted under a slightly positive pres-
sure of dry, pre-purified nitrogen using standard Schlenk line
techniques when appropriate. Unless otherwise noted, all
starting materials were commercially available and used
without further purification. Diethyl ether was refluxed and
distilled from sodium benzophenone ketyl under a nitrogen
atmosphere. t-BuLi was obtained from Acros Organics.
(4)
2) 1.1 R'CHO
R
R
R
R
C
°
-78 C, 0.5h
H
R'
H
R'
OH
or
C
3) hydrolysis
R
R
R H
R
5
6

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Z. Wang et al. / Tetrahedron 62 (2006) 6967–6972
1H and 13C NMR spectra were recorded at 300 and
75.4 MHz, respectively, in CDCl3 or C6D6 solution on
JEOL JNM-AL300 NMR spectrometer.
Compound 3f: colorless liquid, isolated yield 62% (184 mg).
1H NMR (CDCl3): d 0.52 (t, J¼7.2 Hz, 3H), 0.66–0.74 (m,
6H), 1.06–1.13 (m, 6H), 1.84–2.34 (m, 12H), 7.04–7.16
(m, 5H). 13C NMR (CDCl3): d 7.38, 14.05, 14.94, 15.07,
15.15, 18.89, 18.95 (2C), 22.53, 22.86, 28.68, 64.54,
125.46, 126.60, 127.64, 142.41, 142.65, 142.83, 145.75,
147.13. HRMS calcd for C22H32: 296.2504; found:
296.2505.
4.1.1. A typical procedure for the formation of multiply
substituted cyclopentadienes. To a solution of 2a
(1.0 mmol) in Et2O (10 ml) was added t-BuLi (1.5 M pen-
tane solution, 2.0 mmol) slowly at ꢀ78 ꢁC and the mixture
was stirred for 1 h at the same temperature. PhCHO
(1.2 mmol) was added and stirring was continued for 1 h
at ꢀ78 ꢁC. HCl (12 N, 5 ml) was added to the reaction
mixture, and it was stirred for 5 h at room temperature.
The reaction mixture was extracted with diethyl ether and
washed with aqueous NaHCO3, brine, and dried over
MgSO4. The solvent was evaporated in vacuo and the resi-
due was purified by chromatography on silica gel to afford
the corresponding product 3a.
Compound 3g: colorless liquid, isolated yield 26% (47 mg).
1H NMR (CDCl3): d 0.45 (t, J¼7.2 Hz, 3H), 0.89 (t,
J¼6.9 Hz, 3H), 1.01–1.13 (m, 9H), 1.28–2.38 (m, 18H),
5.02 (d, J¼15.9 Hz, 1H), 5.42 (dt, J¼15.6, 6.9 Hz, 1H),
7.17–7.27 (m, 5H). 13C NMR (CDCl3): d 7.42, 14.13,
14.50, 15.17, 15.23, 18.54, 19.00, 19.43, 22.28, 22.69,
28.95, 29.70, 31.82, 33.02, 64.65, 125.87, 127.58, 128.44,
129.01, 133.55, 137.96, 142.56, 143.50, 145.08, 146.46.
HRMS calcd for C27H40: 364.3130; found: 364.3133.
Compound 3a: colorless liquid, isolated yield 74%
(198 mg). 1H NMR (CDCl3): d 0.53 (t, J¼7.2 Hz, 3H),
0.95 (t, J¼7.5 Hz, 3H), 1.02 (s, 3H), 1.07–1.14 (m, 6H),
1.46–2.35 (m, 8H), 7.09–7.35 (m, 5H). 13C NMR (CDCl3):
d 8.23, 14.36, 15.19, 15.35, 18.26, 18.88, 19.26, 21.95,
27.53, 58.20, 126.10, 127.86, 129.64, 138.67, 140.66,
143.40, 145.07, 147.04. HRMS calcd for C20H28:
268.2191; found: 268.2193.
4.1.2. A typical procedure for the formation of dienol 4a
and the acid-promoted cyclization. To a solution of 2c
(0.5 mmol) in Et2O (10 ml) was added t-BuLi (1.5 M
pentane solution, 1.0 mmol) slowly at ꢀ78 ꢁC and the
mixture was stirred for 1 h at the same temperature.
4-Phenylbenzaldehyde (0.6 mmol) was added and stirring
was continued for 1 h at ꢀ78 ꢁC. The reaction mixture
was quenched with aqueous NaHCO3 and extracted with
diethyl ether. The extract was washed with brine and dried
over MgSO4. The solvent was evaporated in vacuo and the
residue was purified by chromatography on Al2O3 to afford
the corresponding alcohol 4a. Colorless liquid, isolated yield
72% (153 mg). 1H NMR (C6D6): d 0.70 (d, J¼2.7 Hz, 1H),
0.79 (t, J¼7.5 Hz, 3H), 0.88 (t, J¼7.2 Hz, 3H), 1.09 (t,
J¼7.8 Hz, 3H), 1.17 (t, J¼7.5 Hz, 3H), 1.84–2.54 (m, 8H),
5.71 (d, J¼2.7 Hz, 1H), 6.98–7.67 (m, 14H). 13C NMR
(C6D6): d 13.39, 13.85, 13.98, 14.71, 21.27, 25.83, 26.34,
26.84, 74.22, 126.84, 126.95, 127.08, 127.19, 127.34,
128.22, 128.96, 129.32, 137.11, 138.48, 138.90, 139.66,
140.61, 141.56, 142.89, 143.37. HRMS calcd for
C31H36O: 424.2766; found: 424.2762.
Compound 3b: colorless liquid, isolated yield 54%
(186 mg). 1H NMR (CDCl3): d 0.55 (t, J¼7.2 Hz, 3H),
0.99 (t, J¼7.5 Hz, 3H), 1.07 (s, 3H), 1.09–1.15 (m, 6H),
1.46–2.41 (m, 8H), 7.16–7.64 (m, 9H). 13C NMR (CDCl3):
d 8.26, 14.36, 15.20, 15.41, 18.28, 18.90, 19.34, 22.05,
27.64, 58.32, 126.56, 126.94, 127.00, 128.70, 129.96,
137.77, 138.76, 140.73, 141.09, 143.72, 144.66, 147.29.
HRMS calcd for C26H32: 344.2504; found: 344.2508.
Compound 3c: colorless liquid, isolated yield 56% (66 mg).
1H NMR (CDCl3): d 0.31 (t, J¼7.5 Hz, 3H), 0.92–1.07 (m,
15H), 1.40–2.28 (m, 12H). 13C NMR (CDCl3): d 7.96,
14.58, 15.09, 15.16, 15.25, 18.06, 18.81, 18.90, 22.19,
23.21, 27.94, 28.27, 57.08, 140.58, 140.96, 143.81,
145.25. HRMS calcd for C17H30: 234.2348; found:
234.2351.
HCl (12 N, 5 ml) was added to the pure alcohol product 4a
with 1 ml Et2O as solvent, and stirring was continued for
5 h at room temperature. The reaction mixture was extracted
with diethyl ether and washed with aqueous NaHCO3, brine,
and dried over MgSO4. The solvent was evaporated in vacuo
and the residue was purified by chromatography on silica gel
to afford 3e in 77% isolated yield.
Compound 3d: colorless liquid, isolated yield 65%
(215 mg). 1H NMR (CDCl3): d 0.58 (t, J¼7.2 Hz, 3H),
0.75 (t, J¼7.5 Hz, 3H), 1.09–1.19 (m, 6H), 1.77–2.47 (m,
8H), 6.71–7.24 (m, 10H). 13C NMR (CDCl3): d 7.34,
13.79, 15.07, 15.16, 18.90, 19.00, 19.45, 22.84, 65.60,
125.75, 125.96, 126.72, 127.64, 127.99, 128.54, 137.32,
141.85, 142.60, 145.56, 145.76, 149.66. HRMS calcd for
C25H30: 330.2348; found: 330.2344.
4.1.3. A typical procedure for the preparation of dienols
and cyclopentadiene derivatives from reactions of
1-lithio-1,3-butadienes IV with aldehydes. 1-Lithio-1,3-
butadiene derivative IVa was generated in situ by lithiation
of its corresponding 1-iodo-1,3-butadiene 2d. 4-Methoxy-
benzaldehyde (1.1 mmol) was then added to IVa at
ꢀ78 ꢁC and the reaction mixture was stirred at the same tem-
perature for 0.5 h. The reaction mixture was then quenched
with saturated aqueous 3 N HCl and extracted with ether.
The extract was washed with water and brine, and dried
over MgSO4. The solvent was evaporated in vacuum to
give a brown oil, which was purified by column chromato-
graphy (silica gel, hexane/CH2Cl2¼1:1) to afford 5a as a
colorless liquid in 53% isolated yield.
Compound 3e: colorless solid, mp 131–132 ꢁC, isolated
yield 77% (313 mg). 1H NMR (CDCl3): d 0.59 (t,
J¼7.2 Hz, 3H), 0.75 (t, J¼7.8 Hz, 3H), 1.17 (t, J¼7.8 Hz,
6H), 1.83–2.54 (m, 8H), 6.80–7.54 (m, 14H). 13C NMR
(CDCl3): d 7.37, 13.83, 15.11, 15.20, 18.89, 18.97, 19.59,
22.99, 65.56, 125.82, 126.32, 126.69, 126.76, 126.90,
128.09, 128.61, 128.74, 136.30, 138.40, 140.88, 141.95,
142.60, 145.20, 145.97, 150.07. HRMS calcd for C31H34:
406.2661; found: 406.2658. Anal. Calcd for C31H34: C,
91.57; H, 8.43. Found: C, 91.53; H, 8.48.

Z. Wang et al. / Tetrahedron 62 (2006) 6967–6972
6971
Compound 5a: colorless liquid, isolated yield 53%
122.34, 122.76, 122.85, 123.33, 125.98, 126.46, 126.94,
133.43, 138.17, 139.51, 139.80, 142.18, 145.04, 145.32,
145.40, 145.61, 149.11, 149.50, 150.41, 150.98. HRMS
calcd for C17H24S: 260.1599; found: 260.1604.
1
(120 mg). H NMR (CDCl3): d 1.08 (d, J¼3.6 Hz, 3H),
2.00 (s, 3H), 2.06 (s, 3H), 2.14 (s, 3H), 3.28 (q,
J¼11.4 Hz, 1H), 3.96 (s, CH3, 3H), 7.04 (d, J¼4.5 Hz,
2H), 7.31 (d, J¼4.5 Hz, 2H). 13C NMR (CDCl3): d 11.07,
11.84, 12.57, 14.87, 50.13, 55.18, 113.59, 129.46, 130.40,
134.91, 135.89, 139.95, 142.35, 157.51. HRMS calcd for
C16H20O: 228.1514; found: 228.1513.
Compound 6a: quenched with saturated NaHCO3. Colorless
liquid, isolated yield 95%, GC yield 99%. 1H NMR (CDCl3,
TMS): d 0.72–0.98 (m, 14H), 1.31–1.43 (m, 8H), 2.03–2.10
(m, 6H), 5.19 (t, J¼7.2 Hz, 1H), 5.78 (s, 1H), 7.21–7.39 (m,
5H). 13C NMR (CDCl3, TMS): d 13.91, 14.22, 14.65, 14.84,
21.54, 21.82, 23.11, 24.41, 29.91, 30.02, 32.15, 32.57, 73.85,
126.06, 126.48, 127.90, 129.22, 135.74, 139.04, 143.47.
HRMS calcd for C23H36O: 328.2766; found: 328.2757.
Compound 5b: colorless liquid, isolated yield 75%
(192 mg), two isomers in 3:1. H NMR (CDCl3) of the
1
main product: d 0.54–0.88 (m, 12H), 1.19–2.35 (m, 8H),
3.05–3.30 (m, 1H), 6.77–7.14 (m, 5H). 13C NMR (CDCl3)
of the main product: d 6.81, 15.21, 15.44, 15.55, 18.53,
19.46, 19.66, 20.74, 52.45, 125.47, 128.09, 128.37,
137.61, 140.63, 141.98, 144.24, 145.04. HRMS calcd for
C19H26: 254.2034; found: 254.2037.
Compound 5f: colorless liquid as a mixture of two double
bond positional isomers (5:2) in 99% combined GC yield
(combined isolated yield 86%). The NMR data of 5f were
consistent with those reported.17
Compound 5c: brown liquid, 3:1 mixture of positional dou-
ble bond isomers, combined isolated yield 71% (175 mg).
1H NMR (CDCl3) of the mixture: d 0.37 (t, J¼7.5 Hz,
3H), 0.85–1.19 (m, 10H), 1.61–2.67 (m, 10H), 3.43 (t,
J¼4.4 Hz, 1H), 5.46 (q, J¼11.1 Hz, 1H), 6.19 (d,
J¼1.8 Hz, 1H), 3.10 (d, J¼1.6 Hz, 0.3H), 6.40–6.46 (m,
1.3H), 7.37 (d, J¼0.9 Hz, 1H), 7.42 (d, J¼0.9 Hz, 0.3H).
13C NMR (CDCl3) of the mixture: d 6.68, 11.23, 11.25,
13.30, 14.30, 14.59, 15.14, 15.36, 18.32, 18.74, 19.59,
20.01, 22.01, 27.62, 27.86, 46.06, 50.54, 51.15, 104.74,
107.58, 110.93, 111.02, 113.16, 129.68, 132.14, 140.21,
140.38, 141.29, 142.00, 145.36, 145.49, 150.89, 152.89,
153.23. HRMS calcd for C17H24O: 244.1827; found:
244.1822.
Compound 6b: colorless liquid, isolated yield 65%, GC
yield 82%. 1H NMR (CDCl3, TMS): d 0.85–0.97 (m,
17H), 1.25–1.59 (m, 10H), 1.93–2.11 (m, 8H), 4.57 (t,
J¼4.8 Hz, 1H), 4.96 (t, J¼7.2 Hz, 1H). 13C NMR (CDCl3,
TMS): d 13.97, 14.18, 14.23, 14.60, 15.00, 19.69, 21.57
(2CH2), 23.18, 24.79, 29.18, 29.89, 31.97, 32.46, 37.87,
72.71, 128.73, 136.77, 139.05, 141.78. HRMS calcd for
C20H38O: 294.2923; found: 294.2929.
Compound 5g: colorless liquid as a mixture of two double
bond positional isomers (4:3) in 85% combined GC yield
(combined isolated yield 70%). The NMR data of 5g were
consistent with those reported.17
Compound 5d: colorless liquid, three isomers in 1:1:1, iso-
lated yield 86% (284 mg). 1H NMR (CDCl3) of the mixture:
d 0.30 (t, J¼7.2 Hz, 3H), 0.81–1.19 (m, 27H), 1.25–1.78 (m,
14H, including 1.43 (d, J¼3.6 Hz, 3H) and 1.70 (d,
J¼3.6 Hz, 3H)), 2.00–2.60 (m, 14H), 3.37 (s, 1H), 3.14
(t, J¼4.2 Hz, 1H), 3.52 (s, 1H), 5.29–5.43 (m, 2H), 6.95
(d, J¼4.2 Hz, 2H), 7.01(d, J¼4.2 Hz, 2H), 7.11(d, J¼4.2 Hz,
2H), 7.34 (d, J¼4.2 Hz, 2H), 7.46 (d, J¼4.2 Hz, 2H). 13C
NMR (CDCl3) of the mixture: d 6.76, 10.85, 10.90, 12.79,
12.90, 13.81, 14.17, 14.26, 15.02, 15.18, 15.36, 15.48,
17.79, 17.83, 18.49, 18.68, 19.44, 19.56, 19.66, 19.94,
20.37, 20.68, 26.31, 28.08, 49.81, 50.40, 52.46, 56.08,
56.82, 111.04, 111.77, 118.96, 119.27, 119.50, 128.64,
128.99, 129.90, 131.25, 131.38, 131.41, 136.50, 139.22,
139.39, 140.11, 142.08, 145.05, 145.22, 145.36, 145.53,
146.14, 146.46, 149.77. HRMS calcd for C19H25Br:
332.1140; found: 332.1134.
Compound 5h: colorless liquid, isolated yield 81%
(321 mg). H NMR (CDCl3): d 0.65–0.70 (m, 5H), 0.86–
1
1.04 (m, 9H), 1.17–1.60 (m, 14H), 1.99–2.59 (m, 8H),
3.23–3.47 (br, 1H), 3.81 (s, 3H), 6.88 (d, J¼4.2 Hz, 2H),
7.14 (d, J¼4.2 Hz, 2H). 13C NMR (CDCl3): d 13.92,
14.00, 14.07, 22.94, 23.07 (2CH2), 23.09, 24.82, 25.46,
26.30, 27.89, 32.68, 33.06, 33.20, 52.52, 55.14, 113.50,
129.45, 130.58, 140.59, 141.08, 141.57, 143.56, 157.52.
HRMS calcd for C28H44O: 396.3392; found: 396.3386.
Acknowledgements
This work was supported by the National Natural Science
Foundation of China, the Major State Basic Research
Development Program (G2000077502-D), and Dow
Corning Corporation. Cheung Kong Scholars Program,
Qiu Shi Science and Technologies Foundation, and BASF
are gratefully acknowledged.
Compound 5e: colorless liquid, three isomers in 2:1:1, iso-
lated yield 78% (203 mg). 1H NMR (CDCl3) of the mixture:
d 0.35 (t, J¼7.2 Hz, 3H), 0.97–1.32 (m, 27H), 1.59 (d,
J¼3.6 Hz, 3H), 1.71(d, J¼3.6 Hz, 3H), 1.76–2.02 (m, 6H),
2.12–2.71 (m, 14H), 3.39 (t, J¼4.2 Hz, 1H), 3.74 (s,
0.5H), 3.90 (s, 0.5H), 5.36 (q, J¼7.2 Hz, 1H), 6.73 (d,
J¼2.7 Hz, 1H), 6.78 (d, J¼2.7 Hz, 1H), 6.80–6.95 (m,
3H), 7.02–7.08 (m, 3H), 7.18 (d, J¼2.7 Hz, 2H). 13C NMR
(CDCl3) of the mixture: d 6.62, 10.84, 11.09, 12.76, 12.82,
13.60, 13.66, 14.17, 14.28, 14.43, 15.16, 15.41, 17.81,
18.44, 19.67, 19.88, 20.00, 20.29, 21.91, 26.16, 27.90,
45.54, 51.06, 51.30, 53.04, 57.20, 111.43, 112.19, 122.25,
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