Controlled synthesis of 1-vinylnaphthalenes versus (E)-α-(1,3-enyn-4- yl)-α,β-unsaturated esters from Morita-Baylis-Hillman bromides: A sequential alkynylation and competitive 6π-electrocyclization versus conjugative transposition of a triple bond

Article abstract of DOI:10.1016/j.tetlet.2013.03.007

An expedient controlled synthesis of 1-vinylnaphthalenes and various dienyne derivatives has been carried out from the Morita-Baylis-Hillman bromides and propargyl acetate or p-nitrophenyl propargyl ether. By judicious choice of base, reaction temperature, and leaving group, a selective synthesis of 1-vinylnaphthalenes and dienynes, (E)-α-(1,3-enyn-4-yl)-α,β- unsaturated esters, could be performed.

Full text of DOI:10.1016/j.tetlet.2013.03.007

Tetrahedron Letters 54 (2013) 2595–2599
Contents lists available at SciVerse ScienceDirect
Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Controlled synthesis of 1-vinylnaphthalenes versus
(E)-a-(1,3-enyn-4-yl)-a,b-unsaturated esters from Morita–Baylis–Hillman
bromides: a sequential alkynylation and competitive 6
versus conjugative transposition of a triple bond
p-electrocyclization
⇑
Jin Woo Lim, Ko Hoon Kim, Se Hee Kim, Jae Nyoung Kim
Department of Chemistry and Institute of Basic Science, Chonnam National University, Gwangju 500-757, Republic of Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
An expedient controlled synthesis of 1-vinylnaphthalenes and various dienyne derivatives has been car-
ried out from the Morita–Baylis–Hillman bromides and propargyl acetate or p-nitrophenyl propargyl
ether. By judicious choice of base, reaction temperature, and leaving group, a selective synthesis of 1-
Received 3 February 2013
Revised 1 March 2013
Accepted 4 March 2013
Available online 20 March 2013
vinylnaphthalenes and dienynes, (E)-
a
-(1,3-enyn-4-yl)-
a
,b-unsaturated esters, could be performed.
Ó 2013 Elsevier Ltd. All rights reserved.
Keywords:
Morita–Baylis–Hillman bromides
Vinylnaphthalenes
Dienynes
Alkynylation
6p
-Electrocyclization
The synthesis of
a
-ethynyl-
a
,b-unsaturated esters has received
via propargyl–allenyl isomerization and a following 1,4-elimina-
tion of AcOH (vide infra, Scheme 4). We expected that a selective
synthesis of 4a and 5a could be achieved by judicious choice of
reaction conditions such as base or reaction temperature.
much attention due to their wide synthetic applicability.1,2 These
compounds have been synthesized in a variety of methods includ-
ing a palladium-catalyzed alkynylation of
a-halo-a,b-unsaturated
esters,1a–d an iridium complex-catalyzed cross-coupling reaction
At the outset of our experiment, a one-pot reaction of MBH bro-
mide 1a and propargyl acetate (2a) was examined in the presence
of CuI (20 mol %) and Cs2CO3 (2.0 equiv) in CH3CN at elevated tem-
perature (50 °C).5 To our delight, vinylnaphthalene 4a (41%) and
dienyne 5a (8%) were formed, albeit in low yields, presumably
via the intermediate 3a. Thus, we decided to prepare 3a and exam-
ine the reaction in the presence of a base in order to find an opti-
mum condition, and the results are summarized in Table 1. The
starting material 3a could be prepared from 1a and 2a at room
temperature in the presence of CuI (20 mol %) and Cs2CO3
(1.5 equiv) in CH3CN in 66% yield according to our previous paper.5
As shown in entry 1, the reaction of 3a in the presence of Cs2CO3
in CH3CN at 50 °C afforded 4a in moderate yield (56%) along with a
low yield of 5a (9%). The result is similar to that of the one-pot
reaction of 1a and 2a (vide supra). The reaction of 3a in the pres-
ence of Et3N showed no reaction at room temperature (entry 2).
The reaction was sluggish even at 50 °C (entry 3).
of terminal alkynes with internal alkynes,1e CuI-catalyzed cross-
coupling reaction between
alkynyl bromides,1f and a DABCO-catalyzed synthesis from allenyl
acetates.1g,h However, the synthesis of
,b-unsaturated esters bear-
ing a 1,3-enyne tether at the -position has not been reported, to
the best of our knowledge.3 This prompted us to investigate the
a-stannyl-a,b-unsaturated esters and
a
a
synthesis of
a-(1,3-enyn-4-yl)-a,b-unsaturated esters starting
from the bromides of Morita–Baylis–Hillman (MBH) adducts.4
Very recently, we reported an efficient synthesis of 1-benzyl-
naphthalene derivatives from Morita–Baylis–Hillman bromides
via a tandem alkynylation, propargyl–allenyl isomerization, and
6p
-electrocyclization sequence, as shown in Scheme 1.5 As a con-
tinuous study, we presumed that 1-vinylnaphthalene 4a and/or
dienyne derivative 5a could be synthesized from 3a, which could
be prepared from MBH bromide 1a and propargyl acetate (2a).
1-Vinylnaphthalene6 4a could be formed via a sequential propar-
gyl–allenyl isomerization, 6
tion of AcOH, while the dienyne derivative 5a could be produced
p
-electrocyclization, and an elimina-
When we carried out the reaction under refluxing conditions
(entry 4), 4a was obtained in good yield (64%). However, the reac-
tion required a long reaction time (72 h). The yield of 4a increased
to 71% by using 3.0 equiv of Et3N (entry 5), and the reaction time
could be shortened. In toluene, the reaction was not completed
⇑
Corresponding author.
E-mail address: kimjn@chonnam.ac.kr (J.N. Kim).
0040-4039/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tetlet.2013.03.007

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J. W. Lim et al. / Tetrahedron Letters 54 (2013) 2595–2599
COOMe
COOMe
Ar
COOMe
H
Ar
Ph
COOMe
Br
CuI, Cs2CO3
Ph
Ref. 5
1a
Ar
Ar
COOMe
COOMe
and/or
Ph
H
COOMe
Ph
OAc
2a
base
This work
1a
CuI, Cs2CO3
CH3CN, rt
OAc
3a
4a
5a
Scheme 1.
Table 1
Table 2
The effect of a leaving group (LG)
Optimization of reaction conditions with 3a
Entry
Conditions
4a (%)
5a (%)
1a
+
CuI
COOMe
b: LG = PhCOO- (61%)
1
2
Cs2CO3 (1.0 equiv), CH3CN, 50 °C, 24 h
Et3N (1.5 equiv), CH3CN, rt, 24 h
Et3N (1.5 equiv), CH3CN, 50 °C, 24 h
Et3N (1.5 equiv), CH3CN, reflux, 72 h
Et3N (3.0 equiv), CH3CN, reflux, 24 h
Et3N (3.0 equiv), toluene, 100 °C, 72 h
DBU (1.0 equiv), CH3CN, rt, 5 h
56
0
9
0
0
0
0
Ph
Cs2CO3
c
d
: LG = PhO- (65%)
3a
4b
5c
6d
7
10
64
71
56
0
0
0
0
16
: LG = p-NO2PhO- (68%)
e: LG = MeSO2- (see text)
CH3CN
rt
LG
LG
3b-d
2b-d
0
47
51
42
36
13
8e
9
DBU (1.5 equiv), CH3CN, rt, 1 h
DBU (1.5 equiv), CH3CN, 50 °C, 1 h
t-BuOK (1.2 equiv), CH3CN, rt, 2 h
TBAF (1.2 equiv), CH3CN, 50 °C, 5 h
Entry
Substrate
Conditiona
4a (%)
5a (%)
10
11f
1
2
3
4
5
6
7
8
3b
3b
3c
3c
3d
3d
3e
3e
A
B
68
0
52
0
45
0
36
25
0
54
0
58
0
62
32
29
a
b
c
d
e
f
Ab
Bc
A
Compound 3a (75%) was recovered.
Compound 3a (9%) was recovered.
Selected as condition A.
Compound 3a (15%) was recovered.
Selected as condition B.
B
Ad
Bd
TBAF (1.0 M in THF) was used, and 3a (45%) was recovered.
a
Condition A: substrate 3 (0.5 mmol), Et3N (3.0 equiv), reflux, 24 h. Condition B:
even after 72 h (entry 6). In all of the reactions employing Et3N (en-
tries 2–6), the formation of dienyne 5a was not observed. The reac-
tions with DBU (entries 7–9) showed completely different results.
Dienyne 5a was formed selectively at room temperature or even at
50 °C in short time; however, the yield was moderate (42–51%).
The reactions of 3a in the presence of t-BuOK (entry 10) or TBAF
(entry 11) did not improve the yield of 4a and/or 5a. Thus, the con-
dition of entry 5 was selected as the best one (condition A) for the
synthesis of vinylnaphthalene and the condition of entry 8 (condi-
tion B) for dienyne.
As a next experiment, some representative substrates 3b–d were
prepared from 1a and propargyl benzoate (2b), phenyl propargyl
ether (2c), and p-nitrophenyl propargyl ether (2d) in order to exam-
ine the effect of a leaving group. The results of 3b–d under the opti-
mized reaction conditions (A and B) are summarized in Table 2
(entries 1–6). The reactions of benzoate 3b (entries 1 and 2) showed
a very similar result to that of the acetate 3a. The reaction of phenyl
ether 3c also showed a similar result (entries 3 and 4). The yield of
4a from the reaction of p-nitrophenyl ether 3d under the condition
A (entry 5) was not improved; however, the reaction under the con-
dition B (entry 6) afforded good yield of 5a (62%).7 In order to pre-
pare the mesylate 3e the reaction between 1a and the mesylate of
propargyl alcohol was examined; however, compound 3e was not
formed at all. Thus, 3e was prepared via the hydrolysis of acetate
3a (K2CO3, H2O/MeOH, rt, 30 min, 85%) and a following mesylation
with CH3SO2Cl (Et3N, CH2Cl2, 0 °C to rt, 2 h, 94%). The reactions of 3e
and Et3N (entry 7) or DBU (entry 8) produced the corresponding
ammonium salts instantaneously even at room temperature and
did not form 4a and/or 5a at this temperature for 6 h. When we
raised the temperature to 50 °C, both reactions provided 4a and
5a as a mixture, unfortunately (entries 7 and 8).
substrate 3 (0.5 mmol), DBU (1.5 equiv), rt, 1 h.
b
Reaction time was 72 h and 3c (9%) was recovered.
Reaction time was 3 h.
Reaction time was 12 h at 50 °C.
c
d
influence of Et3N (3.0 equiv) in refluxing CH3CN solvent (entry 5
in Table 1). For the synthesis of dienyne derivatives, the p-nitro-
phenoxy group was selected as a leaving group in the presence
of DBU (1.5 equiv) in CH3CN at room temperature (entry 6 in Ta-
ble 2). Accordingly, some representative acetates 3f–j were pre-
pared from propargyl acetate (2a) and the corresponding MBH
bromides, and the synthetic results of vinylnaphthalenes 4b–f
are summarized in Table 3.8 The reaction of 4-chlorophenyl deriv-
ative 3f (entry 2) provided 4b in moderate yield (63%), while the p-
methoxyphenyl and p-tolyl derivatives produced good yields of 4c
(74%) and 4d (73%), respectively (entries 3 and 4). The reaction of
furan derivative 3i gave 4-vinylbenzofuran 4e in 70% yield (entry
5). The cinnamyl-substituted substrate 3j afforded a styrene deriv-
ative 4f in 68% yield (entry 6).
Next, various p-nitrophenoxy derivatives 3k–o were prepared
from p-nitrophenyl propargyl ether (2d) and the corresponding
MBH bromides, and the synthetic results of dienyns 5b–f are sum-
marized in Table 4.9 Dienynes 5b–e were obtained in moderate to
good yields (63–75%) from 3k–n in the presence of DBU at room
temperature (entries 2–5). However, the reaction of 3o (entry 6)
showed somewhat different reactivity. Expected compound 5f
was not formed at all, instead a styrene derivative 4f (entry 6 in Ta-
ble 3) was obtained in 61% (vide infra, Scheme 2).
A plausible explanation for the facile formation of a styrene 4f
and a different reactivity between 3a and 3o are shown in Scheme 2.
The 6
proceeded easily under mild condition10 to form 4f as a major prod-
uct. In contrast, the corresponding 6 -electrocyclization of the
p-electrocyclization of allene intermediate I, derived from 3o,
Based on the results, we selected the acetoxy group as a suitable
leaving group for the synthesis of vinylnaphthalenes under the
p

J. W. Lim et al. / Tetrahedron Letters 54 (2013) 2595–2599
2597
Table 3
Table 4
Synthesis of 1-vinylnaphthalene derivatives
Synthesis of dienyne derivatives
Entry Acetates 3a (%)
Products 4b (%)
COOMe
Entry p-Nitrophenyl ethers 3a (%)
Products 5b (%)
COOMe
COOMe
COOMe
1
1
OAc
OAr
3a
3d
(66)
(68)
4a
5a
(71)
(62)
COOMe
COOMe
COOMe
COOMe
2
3
4
5
6
Cl
Cl
2
3
4
Cl
Cl
OAc
OAr
3f (69)
3k (65)
4b (63)
5b (63)
COOMe
COOMe
COOMe
COOMe
MeO
MeO
MeO
MeO
OAc
OAr
3g
3l
(61)
(65)
4c
5c
(75)
(74)
COOMe
COOMe
COOMe
COOMe
Me
O
Me
O
Me
O
Me
O
OAc
OAr
3h (71)
3m (68)
4d (73)
5d (74)
COOMe
COOMe
COOMe
COOMe
5
6
OAc
OAr
3i
3n
(59)
(51)
4e
5e
(70)
(68)
COOMe
COOMe
COOMe
COOMe
Ph
Ph
Ph
Ph
OAc
OAr
5f (0)c
3j (62)
3o (65)
4f (68)
cCompound 4f was obtained in 61% yield.
Conditions: MBH bromide (1.0 mmol), p-nitrophenyl propargyl ether
(1.1 equiv), Cs2CO3 (1.5 equiv), CuI (20 mol %), CH3CN, 20 °C, 12–24 h. Ar is p-
nitrophenyl.
a
Conditions: MBH bromide (1.0 mmol), propargyl acetate (1.1 equiv), Cs2CO3
(1.5 equiv), CuI (20 mol %), CH3CN, 20 °C, 12–24 h.
a
b
Conditions: acetate 3 (0.5 mmol), Et3N (3.0 equiv), CH3CN, reflux, 24 h.
b
Conditions: p-nitrophenyl ether 3 (0.5 mmol), DBU (1.5 equiv), CH3CN, 20 °C,
1 h.
allene intermediate III, derived from 3a, to form IV, required some-
what higher activation energy due to loss of the stabilizing
resonance energy of the benzene ring. Thus we expected that 6p-
which was converted into vinylnaphthalene 4a by an aromatiza-
tion-driven 1,4-elimination of AcOH. Dienyne 5a could be formed
from III via a direct 1,4-elimination of AcOH1g,l,2a,13 or via a 1,3-H
shift to form 6a and a following elimination of AcOH. Compounds
4a and 5a could also be produced via the [3]-cumulene intermedi-
ate V,10,14 which could be formed by 1,4-elimination of AcOH from
3a.13 Although the formations of plausible intermediates III–V
were not observed during the reaction, the involvement of 6a could
be confirmed when we carried out the reaction of 3a in the pres-
ence of a limited amount of DBU (0.3 equiv) at room temperature
for 6 h.15 Under the condition compound 6a was isolated in 9%
along with 5a (17%), and 3a was recovered (40%).
In summary, an expedient synthetic method of 1-vinylnaphtha-
lene and dienyne derivatives was developed from the MBH
bromides and propargyl acetate or p-nitrophenyl propargyl ether.
1-Vinylnaphthalenes were obtained selectively from the acetates
in the presence of Et3N in CH3CN under refluxing conditions, while
dienynes from the p-nitrophenyl ethers under the influence of DBU
at room temperature. Further studies on the reaction mechanism16
and synthetic application of prepared dienynes are under progress.
electrocyclization of the corresponding allene intermediate of 3p
would also be facile, because only one of the two benzene rings of
naphthalene loses its resonance energy. As expected, 1-vinylphe-
nanthrene 4g was formed as a major product (43%) even at room
temperature (condition B) along with a low yield of dienyne 5g
(19%).11 The vinylphenanthrene 4g was prepared in good yield
(80%) using the acetate 3q under the condition A (18 h).
In order to show the generality of the reaction we prepared 3r
and 3s by the reaction of MBH bromide 1a with 2f and 2g, as shown
in Scheme 3. Compound 2f was prepared by acetylation of 3-butyn-
2-ol and compound 2g from p-nitrophenol by Mitsunobu reaction in
the presence of DEAD and PPh3. Introduction of 2f and 2g at the pri-
mary position of the MBH adduct was carried out similarly to obtain
3r and 3s in moderate yields. The reaction of 3r under the condition
A afforded 1-(2-propenyl)naphthalene 4h in good yield (71%). The
stereochemistry of 2-propenyl moiety of 4h was E. The correspond-
ing Z isomer was not formed at all. The reaction of 3s under the con-
dition B gave dienyne derivative 5h in 61% yield, and the E/Z ratio
was about 2:1 (E-isomer 40%, Z-isomer 21%).
The plausible mechanism for the formation of vinylnaphthalene
4a and dienyne 5a, as an example, is proposed in Scheme 4. As in
our previous paper,5 a base-mediated propargyl–allenyl isomeriza-
tion5,10,12 of 3a could produce an allenyl intermediate III. A subse-
Acknowledgments
This research was supported by the Basic Science Research Pro-
gram through the National Research Foundation of Korea (NRF)
funded by the Ministry of Education, Science and Technology
quent 6p-electrocyclization would afford an intermediate IV,

2598
J. W. Lim et al. / Tetrahedron Letters 54 (2013) 2595–2599
Entry 6 in Table 4
COOMe
COOMe
DBU
3o
4f
Ph
Ph
20 o
C
OAr
I
II
ArO
Entry 1 in Table 3
COOMe
COOMe
Et3N
3a
4a
reflux
OAc
IV
III
AcO
COOMe
COOMe
COOMe
Condition A/B
+
LG
5g
4g
3p (65%): LG = p-NO2PhO
3q
For 3p (condition B): 4g (43%), 5g (19%)
For 3q (condition A): 4g (80%), 5g (0%)
(68%): LG = OAc
Scheme 2.
COOMe
Ph
COOMe
Me
Me
OH
Ac2O/Et3N
1a
1a
Condition A
OAc
DMAP/CH2Cl2
rt, 20 h
OAc
2f (70%)
3r
(63%)
Me
4h (71%)
COOMe
Ph
COOMe
DEAD (1.2 equiv)
PPh3 (1.0 equiv)
Ph
Me
Condition B
p-nitrophenol
THF, 0 °C to rt, 8 h
(Ar = p-NO2Ph)
OAr
OAr
3s
(65%)
2g
(68%)
Me
5h
(61%)
trans/cis = 2:1
Scheme 3.
propargyl-allenyl
isomerization (A or B)
COOMe
Ph
1,4-elimination (A or B)
- AcOH
OAc
3a
COOMe
Ph
COOMe
6π-electro
6π-electro
COOMe
Ph
-cyclization (A)
-cyclization (A)
1,4-elimination (A)
- AcOH
4a
H
1,3-H shift
OAc
AcO
IV
III
V
1,4-elimination (B)
Ph
COOMe
OAc
1,3-H shift (B)
1,3-H shift (B)
β-elimination (B)
5a
- AcOH
6a
Scheme 4.
P. Tetrahedron 1998, 54, 135–156; (c) Dai, W.-M.; Wu, Jinlong; Fong, K. C.;
Lee, M. Y. H.; Lau, C. W. J. Org. Chem. 1999, 64, 5062–5082; (d) Dai, W.-M.;
Wu, A.; Hamaguchi, W. Tetrahedron Lett. 2001, 42, 4211–4214; (e)
Hirabayashi, T.; Sakaguchi, S.; Ishii, Y. Adv. Synth. Catal. 2005, 347, 872–
876; (f) Cai, M.; Fang, X.; Dai, R.; Zha, L. Appl. Organomet. Chem. 2009, 23,
229–234; (g) Choe, Y.; Lee, P. H. Org. Lett. 2009, 11, 1445–1448; (h) Kim, H.;
Shin, D.; Lee, K.; Lee, S.; Kim, S.; Lee, P. H. Bull. Korean Chem. Soc. 2010, 31,
742–745; (i) Trost, B. M.; Gunzner, J. L.; Yasukata, T. Tetrahedron Lett. 2001,
42, 3775–3778; (j) Yu, X.; Ren, H.; Xiao, Y.; Zhang, J. Chem. Eur. J. 2008, 14,
(2012R1A1B3000541). Spectroscopic data were obtained from the
Korea Basic Science Institute, Gwangju branch.
References and notes
1. For the synthesis and synthetic applications of
a-ethynyl-a,b-unsaturated
esters, see: (a) Lemay, A. B.; Vulic, K. S.; Ogilvie, W. W. J. Org. Chem. 2006,
71, 3615–3618; (b) Rossi, R.; Bellina, F.; Bechini, C.; Mannina, L.; Vergamini,

J. W. Lim et al. / Tetrahedron Letters 54 (2013) 2595–2599
2599
8481–8485; (k) Yu, X.; Zhou, G.; Zhang, J. Chem. Commun. 2012, 48, 4002–
4004; (l) Deng, Y.; Jin, X.; Fu, C.; Ma, S. Org. Lett. 2009, 11, 2169–2172.
2. (a) Alcaide, B.; Almendros, P.; Martinez del Campo, T. Org. Biomol. Chem. 2012,
10, 7603–7609; (b) Yu, X.; Zhang, J. Adv. Synth. Catal. 2011, 353, 1265–1268; (c)
Zhou, G.; Liu, F.; Zhang, J. Chem. Eur. J. 2011, 17, 3101–3104; (d) Gao, H.; Wu, X.;
Zhang, J. Chem. Eur. J. 2011, 17, 2838–2841; (e) Wang, T.; Zhang, J. Chem. Eur. J.
2011, 17, 86–90; (f) Yu, X.; Du, B.; Wang, K.; Zhang, J. Org. Lett. 2010, 12, 1876–
1879; (g) Liu, F.; Qian, D.; Li, L.; Zhao, X.; Zhang, J. Angew. Chem., Int. Ed. 2010,
49, 6669–6672. and further references cited therein; (h) Tikad, A.; Hamze, A.;
Provot, O.; Brion, J.-D.; Alami, M. Eur. J. Org. Chem. 2010, 725–731; (i) Tsukada,
N.; Ninomiya, S.; Aoyama, Y.; Inoue, Y. Org. Lett. 2007, 9, 2919–2921; (j) Wang,
Y.; Burton, D. J. Org. Lett. 2006, 8, 5295–5298; (k) Tsuboi, S.; Kuroda, H.;
Takatsuka, S.; Fukawa, T.; Sakai, T.; Utaka, M. J. Org. Chem. 1993, 58, 5952–
5957; (l) Yu, X.; Zhang, J. Chem. Eur. J. 2012, 18, 12945–12949; (m) Li, W.; Li, Y.;
Zhou, G.; Wu, X.; Zhang, J. Chem. Eur. J. 2012, 18, 15113–15121.
3. (a) Zou, Y.; Millar, J. G. Tetrahedron Lett. 2010, 51, 1336–1337; (b) Millar, J. G.;
Hoddle, M.; McElfresh, J. S.; Zou, Y.; Hoddle, C. Tetrahedron Lett. 2008, 49, 4820–
4823; (c) Pantke-Bocker, S.; Pohnert, G.; Fischer-Lui, I.; Boland, W. Tetrahedron
1995, 51, 7927–7936; (d) Tellier, F.; Descoins, C.; Sauvetre, R. Tetrahedron 1991,
47, 7767–7774; (e) Andreini, B. P.; Benetti, M. Tetrahedron 1987, 43, 4591–4600;
(f) Istrate, F. M.; Gagosz, F. Org. Lett. 2007, 9, 3181–3184; (g) Liotta, D.; Brown, D.;
Hoekstra, W.; Monahan, R., III Tetrahedron Lett. 1987, 28, 1069–1072.
4. (a) Basavaiah, D.; Rao, A. J.; Satyanarayana, T. Chem. Rev. 2003, 103, 811–891; (b)
Basavaiah, D.; Reddy, B. S.; Badsara, S. S. Chem. Rev. 2010, 110, 5447–5674; (c)
Singh, V.; Batra, S. Tetrahedron 2008, 64, 4511–4574; (d) Declerck, V.; Martinez,
J.; Lamaty, F. Chem. Rev. 2009, 109, 1–48; (e) Kim, J. N.; Lee, K. Y. Curr. Org. Chem.
2002, 6, 627–645; (f) Lee, K. Y.; Gowrisankar, S.; Kim, J. N. Bull. Korean Chem. Soc.
2005, 26, 1481–1490; (g) Gowrisankar, S.; Lee, H. S.; Kim, S. H.; Lee, K. Y.; Kim, J.
N. Tetrahedron 2009, 65, 8769–8780; (h) Shi, M.; Wang, F.-J.; Zhao, M.-X.; Wei, Y.
The Chemistry of the Morita–Baylis–Hillman Reaction; RSC Publishing:
Cambridge, UK, 2011.
5. Lim, J. W.; Kim, K. H.; Kim, S. H.; Kim, J. N. Tetrahedron Lett. 2012, 53, 5449–5454.
6. For the synthesis and synthetic applications of vinylnaphthalenes, see: (a)
Iwasawa, N.; Otsuka, M.; Yamashita, S.; Aoki, M.; Takaya, J. J. Am. Chem. Soc.
2008, 130, 6328–6329; (b) Hayashida, Y.; Nakamura, Y.; Chida, Y.; Nishimura, J.
Tetrahedron Lett. 1999, 40, 6435–6438; (c) Nakamura, Y.; Matsumoto, M.;
Hayashida, Y.; Nishimura, J. Tetrahedron Lett. 1997, 38, 1983–1986; (d) Reddy,
K. L.; Dress, K. R.; Sharpless, K. B. Tetrahedron Lett. 1998, 39, 3667–3670; (e)
Huang, F.-C.; Chan, W.-K.; Warus, J. D.; Morrissette, M. M.; Moriarty, K. J.;
Chang, M. N.; Travis, J. J.; Mitchell, L. S.; Nuss, G. W.; Sutherland, C. A. J. Med.
Chem. 1992, 35, 4253–4255; (f) Kasibhatla, S. R.; Bookser, B. C.; Xiao, W.; Erion,
M. D. J. Med. Chem. 2001, 44, 613–618.
8.26 (s, 1H), 8.73 (d, J = 8.4 Hz, 1H), 9.32 (s, 1H); 13C NMR (CDCl3, 75 MHz) d
52.32, 118.55, 122.04, 123.11, 124.46, 124.56, 127.11, 127.28, 127.35, 128.58,
129.49, 129.98, 130.70, 131.68, 132.19, 134.12, 136.54, 167.36; ESIMS m/z 285
[M+Na]+. Anal. Calcd for C18H14O2: C, 82.42; H, 5.38. Found: C, 82.18; H, 5.52.
Compound 4h: 71%; colorless oil; IR (film) 1719, 1301, 1281 cmÀ1 1H NMR
;
(CDCl3, 300 MHz) d 1.93 (dd, J = 6.6 and 1.8 Hz, 3H), 3.90 (s, 3H), 6.27 (dq,
J = 15.3 and 6.6 Hz, 1H), 7.02 (dd, J = 15.3 and 1.8 Hz, 1H), 7.41–7.55 (m, 2H),
7.85 (d, J = 8.1 Hz, 1H), 8.04 (s, 1H), 8.05 (d, J = 10.8 Hz, 1H), 8.40 (s, 1H); 13C
NMR (CDCl3, 75 MHz) d 18.95, 52.20, 122.67, 123.97, 126.34, 127.05, 127.43,
128.08, 129.89, 129.92, 130.19, 132.77, 133.12, 136.21, 167.34; ESIMS m/z 227
[M+H]+. Anal. Calcd for C15H14O2: C, 79.62; H, 6.24. Found: C, 79.81; H, 6.23.
9. Typical procedure for the synthesis of dienyne 5a: To a stirred solution of MBH
bromide 1a (255 mg, 1.0 mmol) and p-nitrophenyl propargyl ether (2d,
193 mg, 1.1 mmol) in CH3CN (1.5 mL) was added CuI (38 mg, 0.2 mmol) and
Cs2CO3 (489 mg, 1.5 mmol) at room temperature (20 °C), and the reaction
mixture was stirred for 12 h. After the usual aqueous extractive workup and
column chromatographic purification process (hexanes/ether, 6:1), a starting
material 3d was obtained as a pale yellow oil, 239 mg (68%). To a stirred
solution of 3d (176 mg, 0.5 mmol) in CH3CN (1.5 mL) was added DBU (114 mg,
0.75 mmol), and the reaction mixture was stirred at room temperature for 1 h.
After the usual aqueous extractive workup and column chromatographic
purification process (hexanes/ether, 15:1), dienyne 5a was obtained as
colorless oil, 66 mg (62%). Other compounds were synthesized similarly, and
the selected spectroscopic data of 3d, 5a, 5b, 5e, and 5g are as follows.
Compound 3d: 68%; pale yellow oil; IR (film) 1720, 1596, 1439, 1263 cmÀ1 1H
;
NMR (CDCl3, 300 MHz) d 3.35 (t, J = 2.1 Hz, 2H), 3.76 (s, 3H), 4.73 (t, J = 2.1 Hz,
2H), 6.96 (d, J = 9.3 Hz, 2H), 7.24–7.36 (m, 5H), 7.69 (s, 1H), 8.11 (d, J = 9.3 Hz, 2
H); 13C NMR (CDCl3, 75 MHz) d 18.15, 52.34, 56.92, 74.10, 86.64, 115.06,
125.70, 126.75, 128.59, 129.21, 129.50, 134.52, 141.02, 162.55, 167.40 (one
carbon is overlapped); ESIMS m/z 352 [M+H]+. Anal. Calcd for C20H17NO5: C,
68.37; H, 4.88; N, 3.99; Found: C, 68.60; H, 4.96; N, 3.68. Compound 5a: 62%;
colorless oil; IR (film) 1722, 1435, 1261, 1208 cmÀ1 1H NMR (CDCl3, 300 MHz)
;
d 3.81 (s, 3H), 5.56 (dd, J = 11.1 and 2.1 Hz, 1H), 5.72 (dd, J = 17.7 and 2.1 Hz,
1H), 6.03 (dd, J = 17.7 and 11.1 Hz, 1H), 7.32–7.37 (m, 3H), 7.84 (s, 1H), 7.90–
7.95 (m, 2H); 13C NMR (CDCl3, 75 MHz) d 52.84, 85.56, 96.83, 112.58, 117.02,
128.05, 128.51, 130.43, 130.68, 134.28, 145.80, 166.10; ESIMS m/z 213 [M+H]+.
Anal. Calcd for C14H12O2: C, 79.22; H, 5.70. Found: C, 79.50; H, 5.82. Compound
5b: 63%; white solid, mp 82–84 °C; IR (KBr) 2217, 1722, 1261 cmÀ1 1H NMR
;
(CDCl3, 300 MHz) d 3.80 (s, 3H), 5.58 (dd, J = 11.1 and 2.1 Hz, 1H), 5.72 (dd,
J = 17.7 and 2.1 Hz, 1H), 6.02 (dd, J = 17.7 and 11.1 Hz, 1H), 7.32 (d, J = 8.7 Hz,
2H), 7.77 (s, 1H), 7.86 (d, J = 8.7 Hz, 2H); 13C NMR (CDCl3, 75 MHz) d 52.93,
85.27, 97.47, 113.14, 116.87, 128.38, 128.82, 131.55, 132.76, 136.49, 144.18,
165.88; ESIMS m/z 247 [M+H]+, 249 [M+H+2]+. Anal. Calcd for C14H11ClO2: C,
68.16; H, 4.49. Found: C, 68.03; H, 4.71. Compound 5e: 68%; white solid, mp 60–
7. For the elimination of p-nitrophenol to form an alkene, see: Lipshutz, B. H.;
Ghorai, S.; Boskovic, Z. V. Tetrahedron 2008, 64, 6949–6954.
8. Typical procedure for the synthesis of 1-vinylnaphthalene (4a): To a stirred
solution of MBH bromide 1a (255 mg, 1.0 mmol) and propargyl acetate (2a,
108 mg, 1.1 mmol) in CH3CN (1.5 mL) was added CuI (38 mg, 0.2 mmol) and
Cs2CO3 (489 mg, 1.5 mmol) at room temperature (20 °C), and the reaction
mixture was stirred for 12 h. After the usual aqueous extractive workup and
column chromatographic purification process (hexanes/ether, 6:1), starting
material 3a was obtained as a white solid, 180 mg (66%). A mixture of 3a
(136 mg, 0.5 mmol) and Et3N (152 mg, 1.5 mmol) in CH3CN (1.5 mL) was
heated to reflux for 24 h. After removal of volatile materials, the crude product
was purified by column chromatographic purification process (hexanes/ether,
15:1) to afford 4a as colorless oil, 75 mg (71%). Other compounds were
synthesized similarly, and the selected spectroscopic data of 3a, 4a, and 4e-h
are as follows. Compound 3a: 66%; white solid, mp 74–76 °C; IR (KBr) 2239,
62 °C; IR (KBr) 1719, 1436, 1267 cmÀ1 1H NMR (CDCl3, 300 MHz) d 3.79 (s, 3H),
;
5.57 (dd, J = 11.4 and 2.1 Hz, 1H), 5.74 (dd, J = 17.7 and 2.1 Hz, 1H), 6.06 (dd,
J = 17.7 and 11.4 Hz, 1H), 6.48–6.51 (m, 1H), 7.28 (d, J = 3.6 Hz, 1H), 7.51 (d,
J = 1.8 Hz, 1H), 7.74 (s, 1H); 13C NMR (CDCl3, 75 MHz) d 52.76, 85.70, 98.08,
109.14, 112.87, 116.25, 117.05, 127.96, 132.77, 145.10, 151.34, 165.73; ESIMS
m/z 203 [M+H]+. Anal. Calcd for C12H10O3: C, 71.28; H, 4.98. Found: C, 71.55; H,
5.12. Compound 5g: 19%; pale yellow oil; IR (film) 1722, 1435, 1241 cmÀ1 1H
;
NMR (CDCl3, 300 MHz) d 3.86 (s, 3H), 5.49 (dd, J = 11.1 and 2.1 Hz, 1H), 5.59
(dd, J = 17.7 and 2.1 Hz, 1H), 5.93 (dd, J = 17.7 and 11.1 Hz, 1H), 7.42–7.54 (m,
3H), 7.79–7.86 (m, 2H), 8.05 (d, J = 8.1 Hz, 1H), 8.32 (d, J = 7.2 Hz, 1H), 8.64 (s,
1H); 13C NMR (CDCl3, 75 MHz) d 52.92, 85.37, 95.59, 114.83, 116.97, 123.47,
125.05, 126.15, 126.86, 127.66, 128.14, 128.78, 130.83, 130.88, 131.84, 133.47,
143.23, 165.99; ESIMS m/z 263 [M+H]+. Anal. Calcd for C18H14O2: C, 82.42; H,
5.38. Found: C, 82.29; H, 5.53.
1748, 1715 cmÀ1 1H NMR (CDCl3, 300 MHz) d 2.02 (s, 3H), 3.35 (t, J = 2.4 Hz,
;
2H), 3.79 (s, 3H), 4.61 (t, J = 2.4 Hz, 2H), 7.26–7.45 (m, 5H), 7.71 (s, 1H); 13C
NMR (CDCl3, 75 MHz) d 18.11, 20.74, 52.29, 52.71, 74.47, 84.43, 127.09, 128.59,
129.07, 129.56, 134.70, 140.90, 167.49, 170.26; ESIMS m/z 295 [M+Na]+. Anal.
Calcd for C16H16O4: C, 70.57; H, 5.92. Found: C, 70.38; H, 5.98. Compound 4a:
10. For the examples on 6p-electrocyclization at room temperature, see: (a) Zhou,
H.; Xing, Y.; Yao, J.; Chen, J. Org. Lett. 2010, 12, 3674–3677; (b) Zhou, H.; Xing,
Y.; Yao, J.; Lu, Y. J. Org. Chem. 2011, 76, 4582–4590.
11. When we carried out the reaction of 3p under the influence of DBU (1.5 equiv)
in CH3CN at 0 °C, the yield of 5g increased up to 45%. The yield of 4g decreased
to 24% under the condition.
12. For the selected examples on propargyl–allenyl isomerization, see: (a) Xing, Y.;
Wei, Y.; Zhou, H. Curr. Org. Chem. 2012, 16, 1594–1608. and further references
cited therein; (b) Xu, J.; Wang, Y.; Burton, D. J. Org. Lett. 2006, 8, 2555–2558; (c)
Shen, R.; Zhu, S.; Huang, X. J. Org. Chem. 2009, 74, 4118–4123; (d) Huang, X.;
Zhu, S.; Shen, R. Adv. Synth. Catal. 2009, 351, 3118–3122.
13. For the 1,4-elimination of acetic acid from allenylmethyl acetate (or tosylate),
see: (a) Trost, B. M.; Tour, J. M. J. Org. Chem. 1989, 54, 484–486; (b) Bridges, A. J.;
Fischer, J. W. J. Chem. Soc., Chem. Commun. 1982, 665–666; (c) Back, T. G.; Lai, E.
K. Y.; Muralidharan, K. R. J. Org. Chem. 1990, 55, 4595–4602; (d) Kitagaki, S.;
Teramoto, S.; Mukai, C. Org. Lett. 2007, 9, 2549–2552.
71%; colorless oil; IR (film) 1721, 1436, 1309, 1282 cmÀ1 1H NMR (CDCl3,
;
300 MHz) d 3.91 (s, 3H), 5.46 (dd, J = 11.1 and 1.5 Hz, 1H), 5.80 (dd, J = 17.4 and
1.5 Hz, 1H), 7.36 (dd, J = 17.4 and 11.1 Hz, 1H), 7.42–7.49 (m, 1H), 7.50–7.57
(m, 1H), 7.87 (d, J = 8.1 Hz, 1H), 8.04 (d, J = 8.1 Hz, 1H), 8.11 (s, 1H), 8.45 (s, 1H);
13C NMR (CDCl3, 75 MHz) d 52.24, 118.25, 122.86, 123.79, 126.49, 127.09,
128.36, 129.96, 130.78, 132.78, 133.14, 133.63, 136.06, 167.21; ESIMS m/z 213
[M+H]+. Anal. Calcd for C14H12O2: C, 79.22; H, 5.70. Found: C, 79.03; H, 5.96.
Compound 4e: 70%; white solid, mp 78–80 °C; IR (KBr) 1724, 1296, 1241 cmÀ1
;
1H NMR (CDCl3, 300 MHz) d 3.87 (s, 3H), 5.39 (dd, J = 11.1 and 0.9 Hz, 1H), 5.86
(dd, J = 17.7 and 0.9 Hz, 1H), 6.91 (dd, J = 17.7 and 11.1 Hz, 1H), 6.91 (d,
J = 2.1 Hz, 1H), 7.69 (d, J = 2.1 Hz, 1H), 7.97 (s, 1H), 8.01 (s, 1H); 13C NMR (CDCl3,
75 MHz)
133.68, 147.94, 154.77, 167.21; ESIMS m/z 203 [M+H]+. Anal. Calcd for
12H10O3: C, 71.28; H, 4.98. Found: C, 71.44; H, 5.06. Compound 4f: 68%;
colorless oil; IR (film) 1719, 1297, 1236 cmÀ1 1H NMR (CDCl3, 300 MHz) d 3.87
d 52.26, 105.53, 112.10, 116.87, 121.35, 126.42, 129.67, 130.85,
14. For the isomerization of propargyl amides to ynamides via the corresponding
allenyl amides, see: Huang, J.; Xiong, H.; Hsung, R. P.; Rameshkumar, C.;
Mulder, J. A.; Grebe, T. P. Org. Lett. 2002, 4, 2417–2420.
C
;
(s, 3H), 5.18 (dd, J = 11.1 and 2.1 Hz, 1H), 5.73 (dd, J = 17.7 and 1.2 Hz, 1H), 6.62
(dd, J = 17.7 and 11.1 Hz, 1H), 7.23–7.37 (m, 6H), 7.88 (dd, J = 8.1 and 1.8 Hz,
1H), 8.23 (d, J = 1.8 Hz, 1H); 13C NMR (CDCl3, 75 MHz) d 52.15, 115.90, 127.16,
127.59, 128.14, 128.42, 129.18, 129.52, 130.23, 135.03, 135.97, 139.82, 145.06,
166.95; ESIMS m/z 239 [M+H]+. Anal. Calcd for C16H14O2: C, 80.65; H, 5.92.
Found: C, 80.39; H, 5.88. Compound 4g: 80%; white solid, mp 104–106 °C; IR
15. Compound 6a: 9%; colorless oil; IR (film) 2225, 1748, 1722, 1262 cmÀ1 1H NMR
;
(CDCl3, 300 MHz) d 2.01 (s, 3H), 2.80 (t, J = 6.6 Hz, 2H), 3.79 (s, 3H), 4.23 (t,
J = 6.6 Hz, 2H), 7.31–7.36 (m, 3H), 7.82 (s, 1H), 7.90–7.96 (m, 2H); 13C NMR
(CDCl3, 75 MHz) d 20.48, 20.89, 52.79, 62.02, 77.57, 95.12, 112.71, 128.43,
130.23, 130.58, 134.29, 145.62, 166.32, 170.84; ESIMS m/z 273 [M+H]+. Anal.
Calcd for C16H16O4: C, 70.57; H, 5.92. Found: C, 70.76; H, 6.05.
(KBr) 1722, 1437, 1269 cmÀ1
;
1H NMR (CDCl3, 300 MHz) d 3.97 (s, 3H), 5.52
16. During the evaluation process one of the referees suggested the possibility for
the conversion of 5a–4a. However, the reaction of 5a in refluxing CH3CN (24 h)
in the presence of Et3N did not produce any trace amounts of 4a.
(dd, J = 10.8 and 1.5 Hz, 1H), 5.83 (dd, J = 17.4 and 1.5 Hz, 1H), 7.44 (dd, J = 17.4
and 10.8 Hz, 1H), 7.54–7.68 (m, 2H), 7.79–7.87 (m, 2H), 7.98 (d, J = 9.0 Hz, 1H),