Palladium-catalyzed bond reorganization of 1,3-diynes: An entry to diverse functionalized 1,5-dien-3-ynes

Article abstract of DOI:10.1021/jo400276e

A mild and efficient method for the synthesis of functionalized 1,5-dien-3-ynes from 1,3-diynes under Pd^II catalysis is described. The process allows quick and atom-economical assembly of various dihalo-, haloacyl-, and diacyl-substituted 1,5-dien-3-ynes in high yields. The switch of selectivity in the formation of these dienyne products can be controlled by the choice of catalysis system and reaction conditions.

Full text of DOI:10.1021/jo400276e

Note
pubs.acs.org/joc
Palladium-Catalyzed Bond Reorganization of 1,3-Diynes: An Entry to
Diverse Functionalized 1,5-Dien-3-ynes
Wanqing Wu, Yang Gao, Huanfeng Jiang,* and Yubing Huang
School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, People’s Republic of
China
S
* Supporting Information
ABSTRACT: A mild and efficient method for the synthesis of
functionalized 1,5-dien-3-ynes from 1,3-diynes under PdII catalysis is
described. The process allows quick and atom-economical assembly
of various dihalo-, haloacyl-, and diacyl-substituted 1,5-dien-3-ynes in
high yields. The switch of selectivity in the formation of these
dienyne products can be controlled by the choice of catalysis system
and reaction conditions.
mong the challenges currently facing organic chemists is
the development of efficient and elegant chemical
With the hypothesis mentioned above, initial studies were
focused on using 2,7-dimethylocta-3,5-diyne-2,7-diol (1a) as a
model substrate (Table 1). First, when 1a was treated with
PdCl2 (5 mol %) in acetonitrile, no dichloro-1,5-dien-3-yne
product 2a could be detected and 1a was recovered (entry 1).
We then closely examined the influence of different additives
on the reaction. To our delight, a clear improvement of the
yield was observed when an excess amount of LiCl was added
(entry 4), while other additives did not show apparent positive
effects (entries 2 and 3). Further investigation of the solvent
effects revealed that HOAc was the most suitable medium for
this process (entries 4−8). Various palladium sources, including
PdII and Pd0, were also tested, and PdCl2 proved to be optimal,
which afforded 2a in 93% yield (entries 8−12). However, the
addition of ligands, such as triphenylphosphine and 1,10-
phenanthroline, just led to a dramatic decrease in the yield
(entries 13 and 14). After the reaction conditions initiated by
chloropalladation were well-defined, the acetoxy anion was
chosen as the nucleophile instead of the halide ion to perform
this transformation. It was found that lowering the amount of
LiCl and using HOAc/Ac2O as solvent favored the formation
of acetoxychlorination product 3a (entries 16−19). The best
result was obtained when the HOAc/Ac2O ratio was 8/1 (v/v),
giving an 85% yield of 3a (entry 18). Interestingly, when the
reaction was conducted in Ac2O, the diacetoxy derivative 4a
was formed as the major product in 62% yield (entry 20),
which was further improved to 91% with the use of a catalytic
amount of CuCl2·2H2O as additive (entry 22). Notably, the Pd
source played an important role in the success of this
transformation, since no desired products could be detected
in the absence of the Pd catalyst (entries 15 and 23). Thus, the
A
processes that enable the rapid creation of complex skeletons.1
One of the most effective ways of achieving this goal is to
implement the synthesis with a nucleopalladation strategy,
which allows multiple bond-forming events to occur in a single
operation and thereby significantly increases resource efficiency
for the overall process.2 In addition, the development of
complementary sets of catalysts or/and conditions that provide
quick access to various functionalities of broad synthetic uses is
valuable. Thus, the merging of these two topics would provide
interesting possibilities for organic synthesis.
Conjugated molecules, such as enynes, enediynes, and 1,5-
dien-3-ynes, are versatile building blocks for many naturally
occurring biologically active compounds and functional
materials.3,4 In particular, the high π-electron delocalization
behavior in these π-conjugated molecules allows their wide
application in advanced organic materials, such as molecular
wires, nonlinear optics, organic conductors, electrolumines-
cence, etc.3 Despite the significant progress that has been
achieved in the synthesis of conjugated compounds,5 further
advances are still desirable, particularly with regard to the
controlled incorporation of different functional groups by
routine changes to the reaction conditions or/and catalyst
system employed. As part of our continuing program on
nucleopalladation chemistry,6 we envisioned that functionalized
1,5-dien-3-ynes7 could be obtained via bond reorganization of
1,3-diynes bearing propargylic alcohol moieties initiated by
nucleopalladation of the triple bonds. Herein, we disclose a
concise and convenient method for the synthesis of 1,5-dien-3-
yne compounds. This protocol provides a diverse array of
dihalo-, haloacyl-, and diacyl-substituted 1,5-dien-3-ynes that
are suitable for further modifications and synthetic applications.
The selectivity switch in these three kinds of products can be
controlled efficiently by the choice of reaction conditions.
Received: February 13, 2013
Published: April 16, 2013
© 2013 American Chemical Society
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Note
Table 1. Optimization of the Pd-Catalyzed Synthesis of 1,5-
Dien-3-ynes from 1a
Table 2. Pd-Catalyzed Synthesis of Various Functionalized
1,5-Dien-3-ynes
a
additive
(amt (equiv))
product/
b
entry [Pd]/ligand
solvent (v/v)
yield (%)
1
2
3
PdCl2
PdCl2
PdCl2
CH3CN
CH3CN
CH3CN
n.r.
KCl (4.0)
2a/trace
2a/68
CuCl2·2H2O
(4.0)
4
PdCl2
LiCl (4.0)
LiCl (4.0)
LiCl (4.0)
LiCl (4.0)
LiCl (4.0)
LiCl (4.0)
LiCl (4.0)
LiCl (4.0)
LiCl (4.0)
LiCl (4.0)
LiCl (4.0)
CH3CN
THF
2a/82
2a/45
2a/50
2a/n.d.
2a/96 (93)
2a/40
2a/71
n.r.
5
PdCl2
6
PdCl2
DCE
7
PdCl2
DMSO
HOAc
HOAc
HOAc
HOAc
HOAc
HOAc
HOAc
8
PdCl2
9
Pd(OAc)2
Pd2(dba)3
Pd(PPh3)4
Pd/C
10
11
12
13
14
n.r.
PdCl2/PPh3
2a/23
2a/31
PdCl2/1,10-
Phen
15
16
LiCl (4.0)
LiCl (1.0)
HOAc
n.r.
PdCl2
PdCl2
PdCl2
PdCl2
HOAc/Ac2O
(1/1)
3a/62
17
18
19
LiCl (1.0)
LiCl (1.0)
LiCl (1.0)
LiCl (1.0)
HOAc/Ac2O
(4/1)
3a/70
HOAc/Ac2O
(8/1)
3a/89 (85)
3a/58
HOAc/Ac2O
(10/1)
20
21
PdCl2
PdCl2
Ac2O
Ac2O
4a/62
4a/76
CuCl2·2H2O
(1.0)
22
23
PdCl2
CuCl2·2H2O
Ac2O
Ac2O
4a/96 (91)
4a/n.d.
(0.1)
CuCl2·2H2O
(0.1)
a
Unless otherwise noted, all reactions were performed with 1a (0.5
mmol), Pd catalyst (5 mol %), ligand (10 mol %) and additive in the
indicated solvent (2.0 mL) at 60 °C for 12 h. n.r. = no reaction. n.d. =
b
not detected. Determined by GC using dodecane as the internal
standard. Data in parentheses is the isolated yield.
complete selectivity and complementarity for accessing diverse
1,5-dien-3-ynes could be achieved through the employment of
different additives and solvent systems.
To demonstrate the efficiency and generality of this process,
we next examined the transformation of various 1,3-diynes
under the optimized reaction conditions, and the representative
results are summarized in Table 2. Pleasingly, the reactions of
symmetrical (1a−h) and unsymmetrical diynes (1i,j) bearing
tertiary propargyl alcohol moieties proceeded smoothly to
afford the corresponding dichloro- (2a−i), acetoxychloro- (3a−
j), and diacetoxy-1,5-dien-3-yne products (4a−i) in moderate
to high yields (45−93%). The total number of isomers in the
unsymmetrical dienyne products is typically three (E/Z, Z/Z,
and E/E), and their ratios were determined by NMR analysis.8
Generally, the relative rate conversion decreased from alkyl- to
aryl-substituted diynes, indicating that the weak coordination
effect of the aryl groups with the catalyst might have an
influence on the reaction profile. For the phenyl-substituted
diyne 1j, the yield of the acetoxychlorination product 3j was
dropped dramatically to 45%, whereas the dichloro and
diacetoxy products (2j and 4j) could not be obtained.
a
Conditions A: PdCl2 (5 mol %), LiCl (4.0 equiv), HOAc, 60 °C.
Conditions B: PdCl2 (5 mol %), LiCl (1.0 equiv), HOAc/Ac2O (8/1),
60 °C. Conditions C: PdCl2 (5 mol %), CuCl2·2H2O (10 mol %),
b
Ac2O, 60 °C. Unless otherwise noted, yields refer to isolated yields.
c
d
The stereochemistry was not determined. Yields refer to GC yields.
Furthermore, the unsymmetrical diynes 1k−l having both
tertiary and secondary propargyl alcohols could also participate
in this catalytic process, though the yields were far from
satisfactory (18−32%). However, when the diynes containing
secondary or/and primary propargylic alcohols were subjected
to the standard reaction conditions, the bond reorganization
process did not occur at all. The reactivity difference observed
in 1 suggested that the tertiary proparglic alcohol moieties were
critical for this transformation, which was consistent with our
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previous results that the tertiary propargyl alcohols were more
liable to undergo the nucleopalladation process.9 It is also
possible that the alkyl substituents at the tertiary propargylic
carbon would better stabilize the developing positive charge,
thus facilitating the elimination pathway with the aid of acetic
acid.9a,c Moreover, the increased steric repulsion of these alkyl
groups at the propargylic position might also assist the
rearrangement process to form the 1,5-dien-3-yne products. It
is worth mentioning that both the vinyl halide and vinyl acetate
moieties of these dienyne products are poised for subsequent
functionalization, thus allowing for great structural diversity.
The scope of this transformation was further expanded to a
range of carboxylate derivatives (Table 3). Other than acetyl,
The utility of halo-substituted 1,5-dien-3-ynes produced by
this chemistry as useful synthetic intermediates for further
elaborations was demonstrated through Pd-catalyzed Suzuki−
Miyaura and Sonogashira coupling reactions (Scheme 2). For
Scheme 2. Synthetic Applications of Halo-Substituted 1,5-
Dien-3-ynes
Table 3. Pd-Catalyzed Synthesis of Various Diacyl-1,5-dien-
3-ynes from 1a
instance, treatment of compound 7 or 8 with phenylboronic
acid selectively afforded arylated products 9 and 10 in 82% and
85% yields, respectively. In addition, the coupling reaction of 7
with phenylacetylene furnished the conjugated enyne product
11 in 88% yield. The simplicity of this method should make it
valuable to a diversity of dienynes and polyenynes, which may
find potential utilities in materials science and natural product
synthesis.
b
yield (%)
a
entry
1
R
cond
5
6
COCH3
B
C
B
C
B
C
B
C
B
C
B
C
85 (3a)
5 (3a)
8 (4a)
91 (4a)
11 (6a)
90 (6a)
9 (6b)
2
3
4
5
6
COCH2CH3
80 (5a)
6 (5a)
To shed light on the reaction mechanism, several control
experiments were conducted (Scheme 3). Under the standard
CO(CH2)2CH3
CO(CH2)3CH3
COCH(CH3)2
COC(CH3)3
82 (5b)
3 (5b)
84 (5c)
4 (5c)
94 (6b)
10 (6c)
90 (6c)
9 (6d)
Scheme 3. Control Experiments
81 (5d)
8 (5d)
79 (5e)
5 (5e)
89 (6d)
12 (6e)
92 (6e)
a
Conditions B: PdCl2 (5 mol %), LiCl (1.0 equiv), ROH/R2O (8/1),
60 °C. Conditions C: PdCl2 (5 mol %), CuCl2·2H2O (10 mol %),
b
R2O, 60 °C. Yields refer to isolated yields.
different acyl substituents could be incorporated successfully
into the rearrangement sequence. In all the tested cases, the
acyl groups with either elongated carbon chains (n-propionyl,
n-butyryl, valeryl) or increased steric hindrance (i-butyryl,
pivalyl) behaved similarly in terms of reactivity and selectivity,
generating the corresponding chlorocarboxylate (5a−e) and
dicarboxylate 1,5-dien-3-ynes (6a−e) in good to excellent
yields (79−94%).
To our delight, this method could be successfully applied to
the synthesis of bromide-incorporated products when switching
the additive from LiCl to LiBr. Both the dibromo- and
bromoacetoxy-1,5-dien-3-yne products (7 and 8) could be
obtained under the standard conditions in good isolated yields
(94% and 87%, respectively) (Scheme 1).
conditions, the reactions of silyloxy- and methoxy-substituted
1,3-diynes 12 and 13 could give the dichloro- and
chloroacetoxy-1,5-dien-3-ynes 2a and 3a in high yields, while
only a trace amount of diacetoxy product 4a was detected,
suggesting that the formation of these products might proceed
via different pathways. Additionally, when using diyne 14 with
propargylic acetates as the starting material, only 4a could be
obtained in 93% yield. These observations prompted us to
further investigate the origin of the acetate moieties of the
rearrangement products. An isotopic labeling study with
deuterated acetic anhydride as the solvent was performed,
and unlabeled 4a was obtained as a major product, which
clearly demonstrated that the acetate groups of 4a originated
from the substrate and an intramolecular acyl migration should
be involved in the formation of 4.
Scheme 1. Pd-Catalyzed Synthesis of Dibromo- and
Acetoxybromo-1,5-dien-3-ynes
On the basis of the above results, a tentative mechanism for
the switched selectivity in Pd-catalyzed bond reorganization of
1,3-diynes to synthesize functionalized 1,5-dienynes is proposed
(Scheme 4). The pathway on the left was initiated by trans-
halopalladation of the alkyne moiety in 1 to give vinylpalladium
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Note
using light petroleum ether/ethyl acetate as eluent to afford the
desired product 3.
Scheme 4. Proposed Mechanism
General Procedure for the Pd-Catalyzed Synthesis of
Diacetoxy-1,5-dien-3-ynes. A 20 mL Schlenk tube was charged
with 1a (0.5 mmol), PdCl2 (5 mol %), CuCl2·2H2O (10 mol %), and
Ac2O (2.0 mL). The resulting mixture was stirred at 60 °C until the
starting material disappeared, as monitored by TLC. The reaction was
then quenched with saturated aqueous Na2CO3. The aqueous phase
was extracted with diethyl ether (×3), and the combined organic
extracts were washed with brine. After the organic layer was dried over
MgSO4, the solvent was removed under reduced pressure. The residue
was then purified by silica gel chromatography using light petroleum
ether/ethyl acetate as eluent to afford the desired product 4.
3,6-Dichloro-2,7-dimethylocta-2,6-dien-4-yne (2a): yellow oil (94
mg, 93%); 1H NMR (400 MHz, CDCl3) δ 2.02 (s, 6H), 1.95 (s, 6H);
13C NMR (100 MHz, CDCl3) δ 142.5, 107.6, 88.3, 23.0, 21.2; IR
(KBr) 2926, 2856, 2189, 1730, 1462, 1375, 1266, 1123, 802, 740 cm−1;
HRMS (EI/[M]+) calcd for C10H12Cl2 202.0316, found 202.0318.
6-Chloro-2,7-dimethylocta-2,6-dien-4-yn-3-yl acetate (3a): yel-
complex I, which could equilibrate to cumulene intermediate II
through a 1,3-metal shift.10 Then, II would transfer to enyne III
with the elimination of −OH in the presence of acetic acid.
Subsequent nucleophilic attack of halide or acyl anion to III
gave intermediate IV, followed by β-OH elimination to afford
the dihalo- and haloacyl-1,5-dien-yne products 2 and 3.9 For
the pathway on the right, under the treatment of Pd catalyst
and acetic anhydride, diyne 1 was first transformed to diacetate
V, which would undergo 1,2-acyl migration to generate the
acetoxonium species VI,11 followed by isomerization to form
VII and then VIII.12 Finally, the migratory insertion of an
acetate moiety onto the carbene center of VIII via the transient
structure IX occurred to deliver the observed product 4.
In summary, we have developed an efficient method for the
synthesis of functionalized 1,5-dien-3-ynes via Pd-catalyzed
bond reorganization of 1,3-diynes bearing propargylic alcohol
moieties. This general protocol provides rapid access to a
diversity of dihalo-, haloacyl-, and diacyl-1,5-dien-3-ynes in high
yields. The selectivity in product formation can be switched by
using different catalysis systems, and additional mechanistic
studies are provided to rationalize the observed selectivity
differences. Moreover, the 1,5-dien-3-yne derivatives con-
structed by this methodology are readily converted to different
polyconjugated systems, which may have great promise for
their potential applications in materials science and organic
synthesis.
1
low oil (96 mg, 85%); H NMR (400 MHz, CDCl3) δ 2.19 (s, 3H),
1.99 (s, 3H), 1.96 (s, 3H), 1.93 (s, 3H), 1.72 (s, 3H); 13C NMR (100
MHz, CDCl3) δ 168.6, 142.4, 134.0, 125.2, 107.7, 88.7, 85.5, 23.0,
21.2, 20.6, 20.6, 17.7; IR (KBr) 2976, 2873, 1714, 1624, 1464, 1372,
1281, 1168, 842, 607 cm−1; HRMS (ESI/[M + Na]+) calcd for
C12H15O2ClNa 249.0653, found 249.0651.
2,7-Dimethylocta-2,6-dien-4-yne-3,6-diyl diacetate (4a):.7f,g
white solid (114 mg, 91%), mp 46−47 °C (lit.1 mp 47.0−48.9 °C);
1H NMR (400 MHz, CDCl3) δ 2.15 (s, 6H), 1.91 (s, 6H), 1.68 (s,
6H); 13C NMR (100 MHz, CDCl3) δ 168.5, 133.9, 125.3, 85.9, 20.6,
20.6, 17.6; IR (KBr) 2920, 2866, 1755, 1687, 1459, 1393, 1257, 1135,
967 cm−1; HRMS (ESI/[M + Na]+) calcd for C14H18O4Na 273.1097,
found 273.1108.
4,7-Dichloro-3,8-diethyldeca-3,7-dien-5-yne (2b): yellow oil (119
mg, 92%); 1H NMR (400 MHz, CDCl3) δ 2.37 (dq, J = 19.2, 7.6 Hz,
8H), 1.07 (dt, J = 9.3, 7.9 Hz, 12H); 13C NMR (100 MHz, CDCl3) δ
153.1, 107.5, 88.1, 27.7, 25.6, 12.5, 11.5; IR (KBr) 2968, 2873, 2184,
1725, 1619, 1459, 1376, 1241, 1127, 847 cm−1; HRMS (EI/[M]+)
calcd for C14H20Cl2 258.0942, found 258.0942.
7-Chloro-3,8-diethyldeca-3,7-dien-5-yn-4-yl acetate (3b): yellow
oil (121 mg, 86%); 1H NMR (400 MHz, CDCl3) δ 2.37 (q, J = 7.5 Hz,
2H), 2.34 (q, J = 7.5 Hz, 4H), 2.18 (s, 3H), 2.12 (q, J = 7.6 Hz, 2H),
1.04 (m, 12H); 13C NMR (100 MHz, CDCl3) δ 168.7, 152.9, 144.3,
125.0, 107.6, 88.5, 85.5, 27.7, 25.5, 25.0, 22.1, 20.6, 12.6, 12.5, 12.1,
11.5; IR (KBr) 2929, 2853, 2189, 1759, 1668, 1455, 1388, 1212, 1166,
817, 749 cm−1; HRMS (ESI/[M + Na]+) calcd for C16H23O2ClNa
305.1279, found 305.1278.
3,8-Diethyldeca-3,7-dien-5-yne-4,7-diyl diacetate (4b): colorless
oil (138 mg, 90%); 1H NMR (400 MHz, CDCl3) δ 2.31 (q, J = 7.5 Hz,
4H), 2.16 (s, 6H), 2.09 (q, J = 7.5 Hz, 4H), 1.06 (t, J = 7.5 Hz, 6H),
0.97 (t, J = 7.5 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ 168.6, 144.2,
125.1, 85.9, 24.9, 22.1, 20.6, 12.5, 12.0; IR (KBr) 2971, 2843, 2192,
1752, 1459, 1372, 1212, 849, 702 cm−1; HRMS (ESI/[M + Na]+)
calcd for C18H26O4Na 329.1723, found 329.1723.
EXPERIMENTAL SECTION
■
General Procedure for the Pd-Catalyzed Synthesis of
Dichloro-1,5-dien-3-ynes. A 20 mL Schlenk tube was charged
with 1 (0.5 mmol), PdCl2 (5 mol %), LiCl (2 mmol), and HOAc (2.0
mL). The resulting mixture was stirred at 60 °C until the starting
material disappeared, as monitored by TLC. The reaction was then
quenched with saturated aqueous Na2CO3. The aqueous phase was
extracted with diethyl ether (×3), and the combined organic extracts
were washed with brine. After the organic layer was dried over MgSO4,
the solvent was removed under reduced pressure. The residue was
then purified by silica gel chromatography using light petroleum ether
as eluent to afford the desired product 2.
1,4-Dichloro-1,4-dicyclopentylidenebut-2-yne (2c): yellow oil
1
(114 mg, 90%); H NMR (400 MHz, CDCl3) δ 2.47 (m, 8H), 1.77
(m, 8H); 13C NMR (100 MHz, CDCl3) δ 155.5, 103.7, 88.2, 34.1,
33.5, 27.1, 26.3; IR (KBr) 2957, 2874, 2199, 1716, 1609, 1443, 1374,
1238, 1177, 869, 739 cm−1; HRMS (EI/[M]+) calcd for C14H16Cl2
254.0629, found 254.0630.
4-Chloro-1,4-dicyclopentylidenebut-2-yn-1-yl acetate (3c): yellow
oil (115 mg, 83%); 1H NMR (400 MHz, CDCl3) δ 2.48 (m, 6H), 2.31
(m 2H), 2.17 (s, 3H), 1.75 (m, 8H); 13C NMR (100 MHz, CDCl3) δ
168.4, 155.3, 146.2, 122.2, 103.7, 88.9, 85.6, 34.1, 33.5, 31.5, 30.0, 27.1,
26.4, 26.3, 26.3, 20.7; IR (KBr) 2935, 2823, 1765, 1658, 1455, 1395,
1216, 1158, 849, 725 cm−1; HRMS (ESI/[M + Na]+) calcd for
C16H19O2ClNa 301.0966, found 301.0968.
1,4-Dicyclopentylidenebut-2-yne-1,4-diyl diacetate (4c): yellow
oil (136 mg, 90%); 1H NMR (400 MHz, CDCl3) δ 2.46 (m, 2H), 2.27
(m 2H), 2.14 (s, 3H), 1.70 (m, 4H); 13C NMR (100 MHz, CDCl3) δ
168.4, 146.1, 122.3, 86.3, 31. 5, 30.0, 26.4, 26.3, 20.6; IR (KBr) 2950,
General Procedure for the Pd-Catalyzed Synthesis of
Chloroacetoxy-1,5-dien-3-ynes. A 20 mL Schlenk tube was
charged with 1 (0.5 mmol), PdCl2 (5 mol %), LiCl (0.5 mmol),
and HOAc/Ac2O (8/1 v/v, 2.0 mL). The resulting mixture was stirred
at 60 °C until the starting material disappeared, as monitored by TLC.
The reaction was then quenched with saturated aqueous Na2CO3. The
aqueous phase was extracted with diethyl ether (×3), and the
combined organic extracts were washed with brine. After the organic
layer was dried over MgSO4, the solvent was removed under reduced
pressure. The residue was then purified by silica gel chromatography
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2871, 1761, 1655, 1429, 1369, 1201, 1135, 876 cm−1; HRMS (ESI/[M
+ Na]+) calcd for C18H22O4Na 325.1410, found 325.1429.
1,4-Dichloro-1,4-dicyclohexylidenebut-2-yne (2d): yellow oil
(1247 mg, 88%); 1H NMR (400 MHz, CDCl3) δ 2.46 (m, 8H),
1.60 (m, 12H); 13C NMR (100 MHz, CDCl3) δ 149.2, 104.7, 88.3,
33.4, 31.0, 27.4, 26.9, 26.0; IR (KBr) 2932, 2856, 2186, 1729, 1658,
1522, 1445, 1328, 1235, 1135, 861 cm−1; HRMS (EI/[M]+) calcd for
C16H20Cl2 282.0942, found 282.0940.
4-Chloro-1,4-dicyclohexylidenebut-2-yn-1-yl acetate (3d): yellow
oil (121 mg, 79%); 1H NMR (400 MHz, CDCl3) δ 2.43 (m, 6H), 2.18
(s, 3H), 2.16 (m, 2H), 1.64 (m, 2H), 1.57 (m, 10H); 13C NMR (100
MHz, CDCl3) δ 168.7, 149.0, 140.8, 122.3, 104.8, 88.5, 85.7, 33.3,
30.9, 30.9, 27.9, 27.3, 27.2, 26.9, 26.8, 26.1, 26.0, 20.6; IR (KBr) 2936,
2858, 2180, 1752, 1449, 1372, 1227, 1135, 955, 758 cm−1; HRMS
(ESI/[M + Na]+) calcd for C18H23O2ClNa 329.1279, found 329.1282.
1,4-Dicyclohexylidenebut-2-yne-1,4-diyl diacetate (4d):7g yellow
oil (147 mg, 89%); 1H NMR (400 MHz, CDCl3) δ 2.37 (m, 4H), 2.14
(s, 6H), 2.12 (m, 4H), 1.61 (m, 4H), 1.52 (m, 8H); 13C NMR (100
MHz, CDCl3) δ 168.7, 140.8, 122.4, 85.8, 30.8, 27.8, 27.1, 26.8, 26.1,
20.6; IR (KBr) 2933, 2856, 2184, 1764, 1445, 1368, 1193, 875 cm−1;
HRMS (ESI/[M + Na]+) calcd for C20H26O4Na 353.1723, found
353.1730.
26.9, 22.6, 22.5, 22.4, 22.3, 21.0, 20.9, 20.6, 20.5, 19.2, 19.1, 18.4, 18.3,
15.5, 15.4, 14.0; IR (KBr) 2929, 2858, 2182, 1757, 1460, 1373, 1200,
1143, 875, 724 cm−1; HRMS (ESI/[M + Na]+) calcd for
C22H35O2ClNa 389.2218, found 389.2217.
7,12-Dimethyloctadeca-7,11-dien-9-yne-8,11-diyl diacetate (4f):
yellow oil (172 mg, 88%, 31/55/14 mixture of EE/EZ/ZZ isomers);
1H NMR (400 MHz, CDCl3) δ 2.29 (m, 2H), 2.15 (d, J = 2.9 Hz,
6H), 2.05 (m, 2H), 1.90 (d, J = 2.4 Hz, 3H), 1.67 (s, 3H), 1.45 (m,
2H), 1.36 (m, 2H), 1.27 (m, 12H), 0.87 (m, 6H); 13C NMR (100
MHz, CDCl3) δ 168.7, 168.6, 168.4, 168.3, 137.9, 137.8, 137.7, 137.6,
125.6, 125.5, 125.3, 125.2, 86.2, 86.1, 86.0, 85.8, 34.3, 34.2, 31.7, 31.6,
31.5, 31.4, 29.1, 28.9, 28.8, 27.6, 27.5, 27.0, 22.7, 22.6, 22.5, 20.6, 20.5,
18.5, 18.4, 15.5, 15.4, 14.1, 14.0; IR (KBr) 2928, 2859, 2186, 1767,
1460, 1371, 1204, 1123, 882, 728 cm−1; HRMS (ESI/[M + Na]+)
calcd for C24H38O4Na 413.2662, found 413.2664.
4,7-Dichloro-2,3,8,9-tetramethyldeca-3,7-dien-5-yne (2g): yellow
oil (107 mg, 83%, 23/60/17 mixture of EE/EZ/ZZ isomers); 1H
NMR (400 MHz, CDCl3) δ 3.21 (m, 2H), 1.91 (d, J = 4.4 Hz, 3H),
1.83 (s, 3H), 1.05 (d, J = 6.9 Hz, 6H), 1.02 (d, J = 6.8 Hz, 6H); 13C
NMR (100 MHz, CDCl3) δ 151.4, 151.3, 150.6, 150.5, 107.3, 107.2,
106.2, 106.1, 89.1, 88.6, 88.3, 87.8, 34.0, 33.9, 31.2, 20.4, 20.4, 19.7,
15.8, 15.7, 14.0, 13.9; IR (KBr) 2959, 2872, 2185, 1721, 1462, 1376,
1247, 1167, 853, 751 cm−1; HRMS (EI/[M]+) calcd for C14H20Cl2
258.0942, found 258.0938.
4,7-Dichloro-3,8-dimethyldeca-3,7-dien-5-yne (2e): yellow oil
1
(105 mg, 91%, 26/54/20 mixture of EE/EZ/ZZ isomers); H NMR
(400 MHz, CDCl3) δ 2.40 (m, 2H), 2.35 (q, J = 7.5 Hz, 2H), 2.00 (d,
J = 2.4 Hz, 3H), 1.93 (s, 3H), 1.06 (m, 6H); 13C NMR (100 MHz,
CDCl3) δ 147.9, 147.57, 147.54, 107.7, 107.6, 106.98, 106.95, 88.5,
88.4, 88.1, 87.9, 30.0, 27.9, 20.5, 20.45, 18.8, 18.7, 12.3, 11.3; IR (KBr)
2935, 2875, 2166, 1715, 1460, 1383, 1237, 1125, 849, 769 cm−1;
HRMS (EI/[M]+) calcd for C12H16Cl2 230.0629, found 230.0625.
7-Chloro-3,8-dimethyldeca-3,7-dien-5-yn-4-yl acetate (3e): yel-
low oil (105 mg, 83%, 27/50/23 mixture of EE/(EZ,ZE)/ZZ isomers);
1H NMR (400 MHz, CDCl3) δ 2.35 (m, 3H), 2.18 (s, 3H), 2.10 (m,
1H), 1.95 (m, 2H), 1.91 (s, 1.5H), 1.70 (s, 1.5H), 1.05 (m, 6H); 13C
NMR (100 MHz, CDCl3) δ 168.8, 168.7, 168.5, 168.4, 147.8, 147.75,
147.4, 147.3, 139.2, 139.0, 138.9, 125.1, 125.0, 124.8, 124.7, 107.7,
107.6, 107.1, 107.0, 88.9, 88.8, 88.4, 88.3, 85.8, 85.7, 85.4, 85.3, 30.0,
27.9, 27.5, 24.53, 20.6, 20.5, 20.5, 20.4, 18.8, 18.7, 17.9, 17.7, 15.1,
15.0, 12.2, 12.1, 11.7, 11.2; IR (KBr) 2933, 2880, 2184, 1753, 1457,
1375, 1202, 1121, 840, 729 cm−1; HRMS (ESI/[M + Na]+) calcd for
C14H19O2ClNa 277.0966, found 277.0973.
3,8-Dimethyldeca-3,7-dien-5-yne-4,7-diyl diacetate (4e): yellow
oil (125 mg, 90%, 28/55/17 mixture of EE/EZ/ZZ isomers); 1H
NMR (400 MHz, CDCl3) δ 2.31 (dq, J = 7.5, 2.6 Hz, 2H), 2.16 (s,
6H), 2.08 (q, J = 7.6 Hz, 2H), 1.91 (d, J = 1.9 Hz, 3H), 1.68 (s, 3H),
1.05 (t, J = 7.5 Hz, 3H), 0.98 (t, J = 7.6 Hz, 3H); 13C NMR (100
MHz, CDCl3) δ 168.7, 168.6, 168.4, 168.3, 139.1, 138.9, 138.8, 125.2,
125.1, 124.9, 124.82, 86.1, 86.0, 85.8, 85.7, 27.5, 24.5, 20.6, 20.5, 17.9,
17.8, 15.0, 15.0, 12.2, 12.1, 11.7; IR (KBr) 2978, 2876, 2170, 1755,
1489, 1395, 1222, 1143, 880, 755 cm−1; HRMS (ESI/[M + Na]+)
calcd for C16H22O4Na 301.1410, found 301.1416.
7-Chloro-2,3,8,9-tetramethyldeca-3,7-dien-5-yn-4-yl acetate
(3g): yellow oil (102 mg, 72%, 31/51/18 mixture of EE/(EZ,ZE)/
ZZ isomers); 1H NMR (400 MHz, CDCl3) δ 3.15 (m, 1.6H), 2.85 (m,
0.4H), 2.18 (d, J = 1.3 Hz, 3H), 1.85 (m, 3H), 1.61 (s, 3H), 1.02 (m,
12H); 13C NMR (100 MHz, CDCl3) δ 168.8, 168.7, 168.3, 168.2,
151.1, 150.4, 150.3, 142.6, 142.5, 142.3, 124.5, 124.4, 124.0, 123.9,
107.4, 107.3, 106.3, 106.2, 89.4, 88.9, 88.7, 88.1, 86.5, 86.0, 85.8, 85.3,
33.9, 31.4, 31.3, 31.1, 28.2, 20.6, 20.5, 20.4, 20.3, 20.1, 19.7, 15.8, 15.7,
13.9, 13.8, 13.4, 13.3, 10.4, 10.3; IR (KBr) 2968, 2875, 2187, 1766,
1463, 1370, 1283, 1202, 894, 782 cm−1; HRMS (ESI/[M + Na]+)
calcd for C16H23O2ClNa 305.1279, found 305.1272.
2,3,8,9-Tetramethyldeca-3,7-dien-5-yne-4,7-diyl diacetate (4g):
yellow oil (122 mg, 80%, 42/46/12 mixture of EE/EZ/ZZ isomers);
1H NMR (400 MHz, CDCl3) δ 3.08 (m, 0.7H), 2.83 (q, J = 6.9 Hz,
1.3H), 2.16 (d, J = 3.1 Hz, 6H), 1.83 (d, J = 2.0 Hz, 3H), 1.59 (d, J =
8.0 Hz, 3H), 1.04 (d, J = 6.8 Hz, 4H), 0.97 (dd, J = 6.9, 1.7 Hz, 8H);
13C NMR (100 MHz, CDCl3) δ 168.8, 168.7, 168.4, 168.3, 142.6,
142.5, 142.3, 142.2, 124.5, 124.1, 124.0, 86.7, 86.2, 85.5, 31.4, 31.3,
28.2, 20.7, 20.6, 20.3, 20.0, 13.4, 13.3, 10.4, 10.3; IR (KBr) 2915, 2877,
2197, 1787, 1490, 1372, 1299, 1115, 878, 756 cm−1; HRMS (ESI/[M
+ Na]+) calcd for C18H26O4Na 329.1723, found 329.1721.
5,8-Dichloro-2,4,9,11-tetramethyldodeca-4,8-dien-6-yne (2h):
yellow oil (122 mg, 85%, 23/59/18 mixture of EE/EZ/ZZ isomers);
1H NMR (400 MHz, CDCl3) δ 2.28 (dd, J = 7.4, 1.8 Hz, 2H), 2.25
(dd, J = 7.4, 1.8 Hz, 2H), 2.00 (d, J = 3.2 Hz, 3H), 1.92 (d, J = 2.9 Hz,
3H), 1.90 (m, 2H), 0.94 (d, J = 6.6 Hz, 12H); 13C NMR (100 MHz,
CDCl3) δ 145.8, 145.6, 145.5, 145.3, 108.8, 108.7, 108.4, 108.2, 89.0,
88.9, 88.5, 88.4, 45.8, 45.7, 43.6, 43.5, 27.5, 27.4, 27.2, 27.1, 22.5, 22.4,
22.3, 21.4, 21.3, 19.6, 19.5; IR (KBr) 2930, 2863, 1722, 1445, 1393,
1285, 1180, 866, 739 cm−1; HRMS (EI/[M]+) calcd for C16H24Cl2
286.1255, found 286.1256.
8,11-Dichloro-7,12-dimethyloctadeca-7,11-dien-9-yne (2f): yel-
low oil (147 mg, 86%, 26/53/21 mixture of EE/EZ/ZZ isomers);
1H NMR (400 MHz, CDCl3) δ 2.38 (t, J = 7.6 Hz, 2H), 2.32 (m, 2H),
2.00 (d, J = 2.2 Hz, 3H), 1.93 (s, 3H), 1.47 (m, 4H), 1.29 (m, 12H),
0.90 (d, J = 3.1 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ 146.7, 146.5,
146.4, 146.3, 108.1, 108.0, 107.5, 107.4, 88.7, 88.5, 88.4, 88.2, 36.7,
34.7, 31.7, 31.6, 29.1, 28.9, 28.9, 27.7, 27.6, 26.9, 22.6, 22.5, 21.0, 20.9,
19.2, 19.1, 14.1; IR (KBr) 2928, 2861, 2184, 1714, 1601, 1460, 1376,
1256, 866, 727 cm−1; HRMS (EI/[M]+) calcd for C20H32Cl2 342.1881,
found 342.1884.
8-Chloro-2,4,9,11-tetramethyldodeca-4,8-dien-6-yn-5-yl acetate
(3h): yellow oil (116 mg, 75%, 29/51/20 mixture of EE/(EZ,ZE)/ZZ
1
isomers); H NMR (400 MHz, CDCl3) δ 2.21 (m, 6H), 1.96 (m, 2.4
H), 1.93 (m, 1.6 H), 1.89 (m, 1.6 H), 1.86 (m, 2H), 1.68 (m, 1.4 H),
0.91 (m, 12H); 13C NMR (100 MHz, CDCl3) δ 168.6, 168.4, 168.3,
168.2, 136.9, 136.7, 136.6, 136.4, 126.4, 126.3, 126.1, 126.0, 86.6, 86. 5,
86.0, 85.9, 43.4, 43.3, 40.6, 40.5, 27.1, 27.0, 26.7, 26.6, 22.6, 22.3, 20.7,
20.6, 20.5, 20.4, 18.7, 18.6, 15.9, 15.8; IR (KBr) 2988, 2898, 2153,
1754, 1687, 1422, 1381, 1222, 1150, 861, 745 cm−1; HRMS (ESI/[M
+ Na]+) calcd for C18H27O2ClNa 333.1592, found 333.1596.
11-Chloro-7,12-dimethyloctadeca-7,11-dien-9-yn-8-yl acetate
(3f): yellow oil (141 mg, 77%, 31/47/22 mixture of EE/EZ/ZZ
1
isomers); H NMR (400 MHz, CDCl3) δ 3.32 (m, 3H), 2.17 (d, J =
3.5 Hz, 3H), 2.08 (m, 1H), 1.95 (m, 3H), 1.90 (s, 1.5H), 1.69 (s,
1.5H), 1.44 (m, 4H), 1.29 (m, 12H), 0.88 (m, 6H); 13C NMR (100
MHz, CDCl3) δ 168.6, 168.5, 168.4, 168.2, 146.4, 146.2, 146.1, 137.9,
137.7, 137.6, 137.5, 125.6, 125.5, 125.3, 125.2, 108.2, 108.1, 107.6,
107.5, 89.1, 88.8, 88.5, 85.9, 85.8, 85.7, 85.6, 36.8, 34.7, 34.2, 31.7,
31.6, 31.5, 31.4, 29.1, 29.0, 28.9, 28.8, 28.7, 27.8, 27.7, 27.6, 27.5, 27.1,
2,4,9,11-Tetramethyldodeca-4,8-dien-6-yne-5,8-diyl diacetate
(4h): yellow oil (137 mg, 82%, 34/53/13 mixture of EE/EZ/ZZ
1
isomers); H NMR (400 MHz, CDCl3) δ 2.15 (m, 8H), 1.95 (d, J =
7.3, 2H), 1.89 (d, J = 3.7 Hz, 3H), 1.81 (m, 2H), 1.65 (s, 3H), 0.93 (d,
J = 6.6 Hz, 6H), 0.86 (d, J = 6.6 Hz, 6H); 13C NMR (100 MHz,
4584
dx.doi.org/10.1021/jo400276e | J. Org. Chem. 2013, 78, 4580−4586

The Journal of Organic Chemistry
Note
CDCl3) δ 168.6, 168.4, 168.3, 168.2, 136.9, 136.7, 136.6, 136.4, 126.4,
126.3, 126.1, 126.0, 86.6, 86.5, 86.0, 85.9, 43.4, 43.3, 40.6, 40.5, 27.1,
27.0, 26.7, 26.6, 22.6, 22.3, 20.7, 20.6, 20.5, 20.4, 18.7, 18.6, 15.9, 15.8;
IR (KBr) 2958, 2872, 2189, 1766, 1463, 1371, 1201, 1127, 888, 795
cm−1; HRMS (ESI/[M + Na]+) calcd for C20H30O4Na 357.2036,
found 357.2039.
6-Chloro-2,7-dimethylocta-2,6-dien-4-yn-3-yl pentanoate (5c):
yellow oil (113 mg, 84%); H NMR (400 MHz, CDCl3) δ 2.43 (t, J
1
= 7.4 Hz, 2H), 1.98 (s, 3H), 1.95 (s, 3H), 1.92 (s, 3H), 1.71 (s, 3H),
1.68 (m, 2H), 1.39 (m, 2H), 0.93 (t, J = 7.4 Hz, 3H); 13C NMR (100
MHz, CDCl3) δ 171.4, 142.1, 133.6, 125.3, 107.7, 88.6, 85.7, 33.7,
27.0, 22.9, 22.2, 21.1, 20.6, 17.6, 13.7; IR (KBr) 2968, 2852, 1758,
1650, 1473, 1355, 1261, 1158, 868, 742 cm−1; HRMS (ESI/[M +
Na]+) calcd for C15H21O2ClNa 291.1122, found 291.1126.
2,7-Dimethylocta-2,6-dien-4-yne-3,6-diyl dipentanoate (6c): yel-
low oil (150 mg, 90%); 1H NMR (400 MHz, CDCl3) δ 2.41 (t, J = 7.4
Hz, 4H), 1.92 (s, 6H), 1.68 (s, 6H), 1.66 (m, 4H), 1.40 (m, 4H), 0.92
(t, J = 7.4 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ 171.2, 133.4,
125.4, 86.0, 33.7, 27.0, 22.2, 20.6, 17.6, 13.7; IR (KBr) 2930, 2876,
1764, 1682 1475, 1382, 1268, 1142, 946 cm−1; HRMS (ESI/[M +
Na]+) calcd for C20H30O4Na 357.2036, found 357.2034.
(1,4-Dichloro-5-methylhex-4-en-2-yn-1-ylidene)cyclohexane (2i):
1
yellow oil (111 mg, 92%); H NMR (400 MHz, CDCl3) δ 2.45 (m,
4H), 2.02 (s, 3H), 1.95 (s, 3H), 1.60 (m, 6H); 13C NMR (100 MHz,
CDCl3) δ 149.2, 142.5, 107.7, 104.6, 88.5, 88.0, 33.4, 31.0, 27.4, 26.9,
26.0, 23.0, 21.2; IR (KBr) 2935, 2883, 2189, 1715, 1463, 1369, 1257,
1177, 827, 732 cm−1; HRMS (EI/[M]+) calcd for C13H16Cl2 242.0629,
found 242.0628.
4-Chloro-1-cyclohexylidene-5-methylhex-4-en-2-yn-1-yl acetate
(3i) and 6-chloro-6-cyclohexylidene-2-methylhex-2-en-4-yn-3-yl
acetate (3i′): yellow oil (110 mg, 83%, 3i/3i′ = 1/2); 1H NMR
(400 MHz, CDCl3) δ 2.42 (m, 3H), 2.18 (m, 4H), 1.99 (s, 1.7H), 1.96
(s, 1.3H), 1.93 (s, 1.7H), 1.72 (s, 1.3H), 1.60 (m, 6H); 13C NMR (100
MHz, CDCl3) δ 168.6, 168.5, 149.0, 142.2, 140.8, 133.9, 125.3, 122.3,
107.7, 104.7, 88.7, 88.4, 85.8 85.4, 33.3, 30.9, 30.8, 27.8, 27.3, 27.2,
26.9, 26.8, 26.1, 26.0, 23.0, 21.2, 20.6, 20.5, 20.4, 17.7; IR (KBr) 2933,
2893, 2189, 1755, 1466, 1371, 1200, 1178, 880, 712 cm−1; HRMS
(ESI/[M + Na]+) calcd for C15H19O2ClNa 289.0966, found 289.0964.
1-Cyclohexylidene-5-methylhex-4-en-2-yne-1,4-diyl diacetate
6-Chloro-2,7-dimethylocta-2,6-dien-4-yn-3-yl isobutyrate (5d):
1
yellow oil (10 mg, 81%); H NMR (400 MHz, CDCl3) δ 2.69 (m,
1H), 1.98 (s, 3H), 1.96 (s, 3H), 1.92 (s, 3H), 1.71 (s, 3H), 1.25 (d, J =
7.0 Hz, 6H); 13C NMR (100 MHz, CDCl3) δ 174.5, 142.1, 133.5,
125.3, 107.8, 88.5, 85.8, 33.9, 22.9, 21.2, 20.7, 18.9, 17.5; IR (KBr)
2980, 2946, 2902, 2235, 1751, 1461, 1442, 1375, 1339, 1317, 1235,
1112, 881, 759 cm−1; HRMS (ESI/[M + Na]+) calcd for
C14H19O2ClNa 277.0966, found 277.0968.
2,7-Dimethylocta-2,6-dien-4-yne-3,6-diyl bis(2-methylpropa-
noate) (6d): yellow oil (136 mg, 89%); 1H NMR (400 MHz,
CDCl3) δ 2.65 (m, 2H), 1.91 (s, 6H), 1.67 (s, 6H), 1.92 (s, 3H), 1.22
(d, J = 7.0 Hz, 12H); 13C NMR (100 MHz, CDCl3) δ 174.5, 133.1,
125.4, 85.9, 33.9, 20.6, 18.8, 17.4; IR (KBr) 2966, 2931, 2925, 2218,
1750, 1473, 1441, 1385, 1331, 1300, 1245, 1108, 857 cm−1; HRMS
(ESI/[M + Na]+) calcd for C18H26O4Na 329.1723, found 329.1722.
6-Chloro-2,7-dimethylocta-2,6-dien-4-yn-3-yl pivalate (5e): yel-
low oil (106 mg, 79%); 1H NMR (400 MHz, CDCl3) δ 1.97 (d, J = 8.0
Hz, 6H), 1.92 (s, 3H), 1.70 (s, 3H), 1.24 (s, 9H); 13C NMR (100
MHz, CDCl3) δ 175.9, 141.8, 133.2, 125.5, 107.8, 88.4, 85.8, 38.9,
26.5, 22.9, 21.1, 20.6, 17.4; IR (KBr) 2995, 2956, 2908, 2240, 1766,
1489, 1452, 1399, 1351, 1302, 1255, 1119, 892, 782 cm−1; HRMS
(ESI/[M + Na]+) calcd for C15H21O2ClNa 291.1122, found 291.1120.
2,7-Dimethylocta-2,6-dien-4-yne-3,6-diyl bis(2,2-dimethylpropa-
noate) (6e):7g White solid (154 mg, 92%), mp =75−76 °C; 1H NMR
(400 MHz, CDCl3) δ 1.89 (s, 6H), 1.66 (s, 6H), 1.21 (s, 18H); 13C
NMR (100 MHz, CDCl3) δ 175.7, 132.6, 125.6, 85.8, 38.8, 26.9, 20.5,
17.3; IR (KBr) 2972, 2936, 2910, 2210, 1760, 1468, 1450, 1395, 1355,
1308, 1266, 1103, 862 cm−1; HRMS (EI/[M]+) calcd for C20H30O4
334.2144, found 334.2146.
1
(4i): yellow oil (133 mg, 92%); H NMR (400 MHz, CDCl3) δ 2.37
(m, 2H), 2.14 (d, J = 3.2 Hz, 6H), 2.12 (m, 1.6H), 2.07 (br, 0.4H),
1.91 (s, 3H), 1.68 (s, 3H), 1.61 (m, 2H), 1.52 (m, 4H); 13C NMR
(100 MHz, CDCl3) δ 168.6, 168.5, 140.8, 133.9, 125.3, 122.3, 85.9,
85.7, 30.8, 27.8, 27.1, 26.8, 26.1, 20.7, 20.6, 20.5, 17.7; IR (KBr) 2925,
2876, 2192, 1767, 1465, 1370, 1207, 1123, 869, 743 cm−1; HRMS
(ESI/[M + Na]+) calcd for C17H22O4Na 313.1410, found 313.1412.
4-Chloro-1-cyclohexylidene-5-phenylhex-4-en-2-yn-1-yl acetate
(3j) and 6-chloro-6-cyclohexylidene-2-phenylhex-2-en-4-yn-3-yl
acetate (3j′): yellow oil (74 mg, 45%); 1H NMR (400 MHz,
CDCl3) δ 7.32 (m, 5H), 2.48 (m, 4H), 2.30 (s, 3H), 1.99 (s, 3H), 1.61
(m, 6H); 13C NMR (100 MHz, CDCl3) δ 168.3, 149.9, 138.0, 135.7,
129.3, 128.2, 128.0, 127.8, 127.5, 90.2, 86.3, 33.5, 31.0, 27.4, 26.9, 26.0,
20.7, 17.9; IR (KBr) 2189, 1755, 1510, 1371, 1200, 1176, 961, 880,
812 cm−1; HRMS (ESI/[M + Na]+) calcd for C20H21O2ClNa
351.1122, found 351.1120.
6-Chloro-2,7-dimethylocta-2,6-dien-4-yn-3-yl propionate (5a):
1
yellow oil (96 mg, 80%); H NMR (400 MHz, CDCl3) δ 2.46 (q, J
= 7.6 Hz, 2H), 1.99 (s, 3H), 1.95 (s, 3H), 1.92 (s, 3H), 1.71 (s, 3H),
1.21 (t, J = 7.6 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 172.0, 142.2,
133.7, 125.3, 107.7, 88.6, 85.7, 27.4, 23.0, 21.2, 20.6, 17.6, 9.1; IR
(KBr) 2981, 2873, 1752, 1634, 1468, 1380, 1271, 1159, 845, 707 cm−1;
HRMS (ESI/[M + Na]+) calcd for C13H17O2ClNa 263.0809, found
263.0806.
2,7-Dimethylocta-2,6-dien-4-yne-3,6-diyl dipropionate (6a): yel-
low oil (125 mg, 90%); 1H NMR (400 MHz, CDCl3) δ 2.45 (q, J = 7.6
Hz, 4H), 1.93 (s, 6H), 1.68 (s, 6H), 1.19 (t, J = 7.6 Hz, 6H); 13C
NMR (100 MHz, CDCl3) δ 171.9, 133.6, 125.4, 86.0, 27.3, 20.6, 17.6,
9.1; IR (KBr) 2972, 2910, 2210, 1751, 1450, 1395, 1308, 1266, 1212,
1103, 862, 767 cm−1; HRMS (ESI/[M + Na]+) calcd for C16H22O4Na
301.1410, found 301.1410.
6-Chloro-2,7-dimethylocta-2,6-dien-4-yn-3-yl butyrate (5b): yel-
low oil (104 mg, 82%); 1H NMR (400 MHz, CDCl3) δ 2.40 (t, J = 7.4
Hz, 2H), 1.97 (s, 3H), 1.94 (s, 3H), 1.91 (s, 3H), 1.72 (m, 2H), 1.70
(s, 3H), 0.99 (t, J = 7.4 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ
171.1, 142.1, 133.6, 125.3, 107.7, 88.6, 85.7, 35.8, 22. 9, 21.1, 20. 6,
18.5, 17.6, 13.6; IR (KBr) 2988, 2868, 1755, 1645, 1480, 1368, 1277,
1171, 882, 756 cm−1; HRMS (ESI/[M + Na]+) calcd for
C14H19O2ClNa 277.0966, found 277.0960.
2,7-Dimethylocta-2,6-dien-4-yne-3,6-diyl dibutyrate (6b): yellow
oil (144 mg, 94%); 1H NMR (400 MHz, CDCl3) δ 2.37 (t, J = 7.4 Hz,
4H), 1.89 (s, 6H), 1.66 (m, 10H), 0.95 (t, J = 7.4 Hz, 6H); 13C NMR
(100 MHz, CDCl3) δ 171.3, 133.5, 125.3, 85.9, 35.9, 20.5, 18.4, 17.5,
13.5; IR (KBr) 2936, 2888, 1761, 1667, 1479, 1375, 1266, 1125, 956
cm−1; HRMS (ESI/[M + Na]+) calcd for C18H26O4Na 329.1723,
found 329.1725.
3,6-Dibromo-2,7-dimethylocta-2,6-dien-4-yne (7): light yellow
1
solid (137 mg, 94%), mp 88−89 °C; H NMR (400 MHz, CDCl3)
δ 2.04 (s, 6H), 1.97 (s, 6H); 13C NMR (100 MHz, CDCl3) δ 145.1,
95.8, 90.1, 24.2, 23.4; IR (KBr) 2938, 2866, 2188, 1752, 1471, 1390,
1255, 1160, 767, 650 cm−1; HRMS (EI/[M]+) calcd for C10H12Br2
289.9306, found 289.9308.
6-Bromo-2,7-dimethylocta-2,6-dien-4-yn-3-yl acetate (8): light
1
yellow oil (117 mg, 87%); H NMR (400 MHz, CDCl3) δ 2.18 (s,
3H), 2.00 (s, 3H), 1.95 (d, J = 6.0 Hz, 6H), 1.72 (s, 3H); 13C NMR
(100 MHz, CDCl3) δ 168.5, 145.0, 133.9, 125.3, 95.9, 90.0, 86.0, 24.1,
23.4, 20.6, 17.7; IR (KBr) 2966, 2856, 1765, 1622, 1462, 1375, 1269,
1113, 802, 681 cm−1; HRMS (ESI/[M + Na]+) calcd for
C12H15O2BrNa 293.0148, found 293.0152.
(2,7-Dimethylocta-2,6-dien-4-yne-3,6-diyl)dibenzene (9): pale
1
yellow solid (117 mg, 82%), mp 95−96 °C; H NMR (400 MHz,
CDCl3) δ 7.30 (m, 6H), 7.25 (m, 4H), 2.09 (s, 6H), 1.81 (s, 6H); 13
C
NMR (100 MHz, CDCl3) δ 141.4, 139.8, 129.2, 127.9, 126.5, 119.7,
93.4, 24.1, 21.5; IR (KBr) 2914, 2139, 1730, 1643, 1462, 1375, 1266,
1123, 874, 746, 545 cm−1; HRMS (EI/[M]+) calcd for C22H22
286.1722, found 286.1726.
2,7-Dimethyl-6-phenylocta-2,6-dien-4-yn-3-yl acetate (10): light
1
yellow solid (114 mg, 85%), mp 88−89 °C; H NMR (400 MHz,
CDCl3) δ 7.30 (m, 4H), 7.23 (m, 1H), 2.12 (d, J = 8.3 Hz, 6H), 1.91
(s, 3H), 1.81 (s, 3H), 1.68 (s, 3H); 13C NMR (100 MHz, CDCl3) δ
168.6, 143.6, 139.0, 131.2, 129.2, 128.0, 126.8, 126.2, 118.8, 93.6, 85.8,
24.1, 21.6, 20.6, 17.6; IR (KBr) 2915, 2197, 1769, 1490, 1447, 1372,
4585
dx.doi.org/10.1021/jo400276e | J. Org. Chem. 2013, 78, 4580−4586

The Journal of Organic Chemistry
Note
1299, 1207, 1115, 958, 878, 756, 693 cm−1; HRMS (ESI/[M + Na]+)
calcd for C18H20O2Na 291.1356, found 291.1355.
Sato, F. J. Am. Chem. Soc. 2003, 125, 14163−14167. (e) Nakano, Y.;
Ishizuka, K.; Muraoka, K.; Ohtani, H.; Takayama, H.; Sato, F. Org. Lett.
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(6) For selected examples, see: (a) Wu, W.; Jiang, H. Acc. Chem. Res.
2012, 45, 1736−1748. (b) Zhou, P.; Huang, L.; Jiang, H.; Wang, A.;
Li, X. J. Org. Chem. 2010, 75, 8279−8282. (c) Zhou, P.; Zheng, M.;
Jiang, H.; Li, X.; Qi, C. J. Org. Chem. 2011, 76, 4759−4763. (d) Wu,
W.; Jiang, H.; Gao, Y.; Huang, H.; Zeng, W.; Cao, D. Chem. Commun.
2012, 48, 10340−10342.
2,7-Dimethyl-6-(phenylethynyl)octa-2,6-dien-4-yn-3-yl acetate
1
(11): light yellow solid (128 mg, 88%), mp 101−102 °C; H NMR
(400 MHz, CDCl3) δ 7.45 (m, 2H), 7.31 (m, 3H), 2.19 (s, 3H), 2.12
(s, 3H), 2.08 (s, 3H), 1.99 (s, 3H), 1.72 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 168.7, 154.7, 132.5, 131.4, 128.2, 128.1, 125. 8, 123.4, 101.1,
91.3, 89.6, 86.0, 84.6, 22.9, 20.6, 17.6; IR (KBr) 2925, 2346, 2192,
1767, 1465, 1370, 1201, 1123, 1089, 802, 743, 665 cm−1; HRMS (ESI/
[M + Na]+) calcd for C20H20O2Na 315.1356, found 315.1358.
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Nakayama, H.; Shirakawa, K. Synthesis 2005, 1991−2007. (f) Cho, E.
J.; Kim, M.; Lee, D. Eur. J. Org. Chem. 2006, 3074−3078. (g) Ohe, K.;
Fujita, M.; Matsumoto, M.; Tai, Y.; Miki, K. J. Am. Chem. Soc. 2006,
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ASSOCIATED CONTENT
■
S
* Supporting Information
Text and figures giving 1H and 13C NMR spectra for
compounds 1b,e−m, 2a−i, 3a−j, 4a−i, 5a−e, 6a−e, and 7−
11 and additional characterization data. This material is
available free of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*H.J.: e-mail, jianghf@scut.edu.cn; fax and tel, (+86) 20-
87112906.
■
(8) See the Supporting Information for details.
(9) (a) Jiang, H.; Liu, X.; Zhou, L. Chem. Eur. J. 2008, 14, 11305−
11309. (b) Jiang, H.; Qiao, C.; Liu, W. Chem. Eur. J. 2010, 16, 10968−
10970. (c) Jiang, H.; Gao, Y.; Wu, W.; Huang, Y. Org. Lett. 2013, 15,
238−241.
(10) (a) Takahashi, Y.; Tsutsumi, K.; Nakagai, Y.; Morimoto, T.;
Kakiuchi, K.; Ogoshi, S.; Kurosawa, H. Organometallics 2008, 27, 276−
280. (b) Lee, D.; Kim, M. Org. Biomol. Chem. 2007, 5, 3418−3427.
(11) (a) Rautenstrauch, V. J. Org. Chem. 1984, 49, 950−952.
(b) Caruana, P. A.; Frontier, A. J. Tetrahedron 2007, 63, 10646−
10656.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This work was supported by the National Natural Science
Foundation of China (21202046 and 20932002), the National
Basic Research Program of China (973 Program)
(2011CB808600), the Changjiang Scholars and Innovation
Team Project of Ministry of Education, the Guangdong Natural
Science Foundation (S2012040007088), the China Postdoc-
toral Science Foundation (2012T50673 and 2011M501318),
and the Fundamental Research Funds for the Central
Universities (2012ZP0003 and 2012ZB0011).
(12) (a) Nakamura, I.; Bajracharya, G. B.; Mizushima, Y.; Yamamoto,
Y. Angew. Chem., Int. Ed. 2002, 41, 4328−4331. (b) Jiang, H.; Pan, X.;
Huang, L.; Zhao, J.; Shi, D. Chem. Commun. 2012, 48, 4698−4700.
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