N-heterocyclic carbene-catalysed Peterson olefination reaction

Article abstract of DOI:10.1016/j.tet.2015.11.044

N-heterocyclic carbenes (NHCs) have been utilised as highly efficient organocatalysts to catalyse Peterson olefination reaction of aldehydes with trimethylsilylketene ethyl trimethylsilyl acetal or fluoro(trimethylsilyl)ketene ethyl trimethylsilyl acetal to produce the corresponding functionalized olefines in 34-93% yields with excellent stereoselectivities.

Full text of DOI:10.1016/j.tet.2015.11.044

Tetrahedron 72 (2016) 472e478
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
N-heterocyclic carbene-catalysed Peterson olefination reaction
,
b
,
a
,
,
,c,
*
Ying Wang a, Guang-Fen Du a , Cheng-Zhi Gu c, Fen Xing a, Bin Dai a c, Lin He a
*
a School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region, PR China
b Laboratory of Materials-Oriented Chemical Engineering of Xinjiang Uygur Autonomous Region, Shihezi, Xinjiang Uygur Autonomous Region, PR China
c Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Shihezi, Xinjiang Uygur Autonomous Region, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
N-heterocyclic carbenes (NHCs) have been utilised as highly efficient organocatalysts to catalyse Peterson
olefination reaction of aldehydes with trimethylsilylketene ethyl trimethylsilyl acetal or fluoro(-
trimethylsilyl)ketene ethyl trimethylsilyl acetal to produce the corresponding functionalized olefines in
34e93% yields with excellent stereoselectivities.
Received 30 September 2015
Received in revised form 16 November 2015
Accepted 19 November 2015
Available online 22 November 2015
Ó 2015 Elsevier Ltd. All rights reserved.
Keywords:
N-heterocyclic carbene
Peterson olefination
Functionalized olefine
Silyl ketene acetal
1. Introduction
nucleophilic organocatalysts can promote a wide range of Umpo-
lung reactions8 and other transformations.9 In particular, NHCs
Functionalized olefines and their fluorinated analogues are con-
sidered to be versatile building blocks in organic synthesis. Fluo-
roolefines are of particular importance owing to their unique
properties and significant applications,1 i.e., these moieties can serve
as amide isostere2 and utilised widely in the synthesis of peptido-
exhibit high reactivity toward the activation of silicon-based re-
agents,10 i.e., only 0.01 mol % NHC can efficiently promote the
cyanation reaction of TMSCN and aldehydes.11 Based on this nu-
cleophilic activation strategy, NHC-catalysed trifluoromethylation
reaction,12a Mukaiyama aldol reaction,12b-d ring-opening reac-
tion,12e silyl-Reformatsky reaction,12f-g pentafluorophenylation
reaction12h and polymerisation reaction13 have been developed in
recent years. In line with our continue interest of NHC catalysis, we
envisioned that NHCs could be utilised as nucleophilic catalysts to
mediate Peterson olefination reaction between silyl ketene acetals
and aldehydes.
mimetics.3 The olefination reaction of
a-silyl carbanionwith carbonyl
compounds, also known as Peterson olefination,4 provide facile ac-
cess to functionalized olefines stereoselectively. More interestingly,
compared with phosphorus reagents, the higher reactivity of a-silyl
carbanion and simple purification procedure make Peterson olefi-
nation to be an attractive alternative to Wittig reaction.5 However,
stoichiometric amount of strong bases, such as n-BuLi, LDA and silyl
Grignard reagents are generally necessary for the in situ generationof
2. Results and discussion
the active
a-silyl carbanion species, which makes base sensitive
substrates can not be well tolerated. Therefore, the development of
more convenient and mild methods for Peterson olefination reaction
is highly valuable. Recently, Mukaiyama reported that silyl ketene
acetals can be utilised as stable precursors of silyl carbanions to un-
dergo Peterson olefination reaction with aldehydes under mild con-
ditions, which provide a novel protocol for the construction of
functionalized olefines.6
With this idea in mind, we began our study with the commer-
cially available silyl ketene acetal 1a and p-chlorobenzaldehyde 2a.
To our delight, in the presence of 5 mol % stable NHC 4 (1,3-bis-(2,6-
diisopropylphenyl)imidazol-2-ylidene, IPr),14 the reaction pro-
ceeded very smoothly in THF at room temperature to afford the
corresponding a,b-unsaturated ester 3a in 71% yield with excellent
E/Z selectivity (Table 1, entry 1). Encouraged by this result, several
other NHCs were subsequently tested for the reaction. NHCs de-
rived from imidazolium can promote the reaction efficiently,
whereas NHC generated from the saturated imidazolinium showed
very low reactivity (Table 1, entries 2e5). Unfortunately, NHCs
derived from both thiazolium and triazolium can not catalyse this
reaction (Table 1, entries 6e8). A brief screening of reaction media
The past decade has witnessed tremendous progress of N-het-
erocyclic carbene (NHC) catalysis.7 This important type of
* Corresponding authors. E-mail addresses: duguangfen@shzu.edu.cn (G.-F. Du),
helin@shzu.edu.cn (L. He).
http://dx.doi.org/10.1016/j.tet.2015.11.044
0040-4020/Ó 2015 Elsevier Ltd. All rights reserved.

Y. Wang et al. / Tetrahedron 72 (2016) 472e478
473
Table 1
Table 2 (continued )
Screening of reaction conditionsa
Entry
R
Time (h)
12
Product
E/Zb
Yield (%)c
5
3e
>25:1
54
O2N
6
7
12
12
3f
>25:1
>25:1
91
82
3g
8
12
3h
>25:1
93
9
12
12
12
3i
>25:1
>25:1
>25:1
85
82
87
H3C
10
11
3j
H3CO
Entry
NHC (mol %)
Solvent
Time (h)
E/Zb
Yieldc
1
2
3
4
5
6
7
8
4, (5)
THF
THF
THF
THF
THF
THF
THF
THF
CH3CN
CH2Cl2
toluene
CH3CN
CH3CN
4
4
8
>25:1
>25:1
18:1
24:1
/
/
/
/
>25:1
>25:1
12:1
>25:1
/
71%
89%
80%
89%
8%
Trace
Trace
Trace
70%
59%
69%
85%
Trace
t
5a, BuOK, (5)
3k
t
5b, BuOK, (5)
t
5c, BuOK, (5)
8
H3CO
t
6, BuOK, (5)
12
12
12
12
12
12
12
8
12
12
3l
>25:1
91
t
7a, BuOK, (5)
t
7b, BuOK, (5)
t
8, BuOK, (5)
Cl
9
4, (5)
4, (5)
4, (5)
4, (5)
4, (1)
13
14
12
12
3m
3n
>25:1
>25:1
91
88
10
11
12
13
12
a
Reaction conditions: NHC precursors (6 mol %), base (5 mol %), 1a (1.5 equiv), 2a
(1.0 equiv), room temperature.
Br
b
Determined by 1H NMR analysis of the crude products.
15
16
12
12
3o
3p
>25:1
>25:1
76
88
c
Isolated total yields of Z and E-isomers.
Cl
revealed that CH3CN was the best choice in terms of yields and
selectivities (Table 1, entries 9e12). Reduction NHC loading to
1 mol % resulted in dramatic decrease of catalytic efficiency (Table 1,
entry 13).
With the optimal reaction conditions in hand, the scope of this
olefination reaction was next examined. Both aromatic and ali-
phatic aldehydes are suitable for the olefination reaction (Table 2).
For aromatic aldehydes, the electronic properties and varied posi-
tions on the aromatic ring had no obvious effects on the reaction
yields and selectivities (Table 2, entries 1e10). Interestingly, het-
eroaromatic aldehydes such as furfural and 2-thenaldehyde
Cl
17
18
12
12
3q
3r
>25:1
>25:1
56
83
19
20
21
22
12
12
15
15
3s
3t
>25:1
>25:1
14:1
78
57
70
53
O
S
Table 2
Evaluation of aldehydesa
3u
3v
>25:1
Entry
R
Time (h)
Product
E/Zb
Yield (%)c
23
24
15
15
3w
3x
>25:1
>25:1
70
34
1
2
3
4
12
12
12
12
3a
3b
3c
3d
>25:1
>25:1
>25:1
>25:1
85
71
88
68
Cl
F
Br
NC
a
1a (1.5 equiv), 2 (1.0 equiv).
b
c
Determined by 1H NMR analysis of the crude products.
Isolated total yields of Z and E-isomers.

474
Y. Wang et al. / Tetrahedron 72 (2016) 472e478
performed very well, producing the desired products in good yields
with excellent E-selectivity (Table 2, entries 19 and 20). However,
when trans-cinnamaldehyde was employed for the reaction, the
corresponding olefin can be isolated in good yield, but the E/Z se-
lectivities reduced to 14:1 (Table 2, entry 21). Gratifyingly, when
aliphatic aldehydes were introduced to reaction, the final products
can be isolated in good yields with excellent selectivities (Table 2,
entries 22 and 23). Notably, 2,2,2-trifluoroacetophenone can
transform into the desired product stereoselectively, albeit in low
yield (Table 2, entry 24).
To extend the utility of this protocol, we further studied the
similar Peterson fluoroolefination reaction. Under the optimal re-
action conditions, fluoro(trimethylsilyl)ketene ethyl trimethylsilyl
acetal 1b underwent these type of fluoroolefination smoothly. As
shown in Table 3, a great variety of aromatic aldehydes and het-
Table 3
NHC-catalysed Peterson fluoroolefination reactiona
eroaromatic aldehydes reacted with
well, affording the corresponding
a
-fluoro ketene acetal 1b very
a
-fluoroolefines in high yields
with excellent Z-selectivity. The fluoroolefination of aliphatic al-
dehyde was also attempted and the final product was isolated in
moderate yield with high Z-selectivity (Table 3, entry 16).
Based on previous studies on NHC-catalysed Mukaiyama aldol
reaction, a possible mechanism was proposed and depicted in
Scheme 1. NHC attack silyl ketene acetal to generate the reactive
hexavalent silicon intermediate I, which might trigger the follow-
ing Mukaiyama aldol reaction with aldehyde to produce in-
termediate II, and after syn-elimination, could produce the desired
product.
Entry
R
Time (h)
Product
Z/Eb
Yieldc
1
2
3
4
6
6
4a
4b
4c
4d
>25:1
>25:1
>25:1
>25:1
88
84
77
79
Cl
F
12
12
5
6
7
8
12
12
15
12
4e
4f
>25:1
>25:1
>25:1
>25:1
82
79
75
79
H3C
Scheme 1. NHC-catalysed Peterson olefination reaction.
4g
4h
H3CO
The mechanism was further investigated through NMR experi-
ments. A 1:1 mixture of silyl ketene acetal 1a and NHC 4 was
detected by 1H NMR and 13C NMR, respectively. 1H NMR indicated
that the characteristic peaks of TMS groups moved from 1.91, 0.38,
0.03, ꢀ1.43 ppm to 1.93, 0.40, 0.05, ꢀ1.42 ppm, while the charac-
teristic peaks of 13C NMR moved from 0.22, 0.14, 0.08, 0.06 ppm to
0.21, 0.12, 0.07 and 0.05 ppm, respectively. These results indicate
that NHC might react with silyl ketene acetal to generate in-
termediate I and initiate the reaction.
9
12
4i
>25:1
85
Cl
10
11
10
8
4j
>25:1
>25:1
82
83
4k
3. Conclusions
In summary, the first NHC-catalysed Peterson olefination re-
action of silyl ketene acetals and carbonyl compounds was de-
veloped. The extremely mild conditions, simple procedure and
excellent stereoselectivities provide a novel protocol for the syn-
thesis of these important building blocks.
Cl
12
13
14
6
15
12
4l
>25:1
>25:1
>25:1
52
61
55
Cl
O
O
4m
4n
4. Experimental section
4.1. General methods
O
S
15
16
12
12
4o
4p
>25:1
63
43
Unless otherwise indicated, all reactions were conducted under
nitrogen atmosphere in oven-dried glassware with magnetic stir-
ring bar. Column chromatography was performed with silica gel
(200e300 mesh) and analytical TLC on silica gel 60-F254. 1H NMR
(400 MHz, CDCl3), 13C NMR (100 MHz, CDCl3) and spectra were
recorded on a Bruker-DMX 400 spectrometer in CDCl3, with tet-
15:1
ramethylsilane as an internal standard and reported in ppm (d). N-
heterocyclic carbene salts 5b and 5c were purchased from Sigma-
eAldrich and TCI. Other NHCs were prepared according to
a
1a (1.5 equiv), 2 (1.0 equiv).
b
c
Determined by 1H NMR analysis of the crude products.
Isolated total yields of Z and E-isomers.

Y. Wang et al. / Tetrahedron 72 (2016) 472e478
475
literature procedure.14,15a Silyl ketene acetals 1a and 1b were pur-
chased from TCI. All other chemicals were obtained from com-
mercial supplies and used as received. Anhydrous THF and toluene
were distilled from sodium and benzophenone. CH2Cl2 and CH3CN
were distilled from calcium hydride.
1H), 7.57e7.48 (m, 2H), 6.56 (d, J¼16.0 Hz, 1H), 4.30 (q, J¼7.2 Hz,
2H), 1.37 ppm (t, J¼7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3)
¼167.0,
d
144.6, 134.2, 133.3, 131.9, 129.8, 128.6, 128.5, 127.7, 127.2, 126.7,
123.5, 118.4, 60.5, 14.3 ppm.
4.2.9. Ethyl (E)-3-(p-tolyl)acrylate (3i).15d 1H NMR (400 MHz,
4.2. General procedure for N-heterocyclic carbene-catalysed
Peterson olefination reaction
CDCl3)
d
¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39 (d,
J¼16.0 Hz, 1H), 4.25 (q, J¼7.2 Hz, 2H), 2.37 (s, 3H), 1.32 ppm (t,
J¼7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3)
¼167.1, 144.5, 140.6,
d
NHC 4 (6.0 mg, 0.015 mmol) was added to a solution of aldehyde
2 (0.3 mmol) and silyl ketene acetal (1a or 1b, 0.45 mmol) in an-
hydrous CH3CN (1.0 mL) at 0ꢁ C. The reaction mixture was then
stirred at room temperature until full consume of the starting al-
dehyde indicated by TLC. The ratio of E/Z was determined by 1H
NMR analysis of the crude products and the configurations were
assigned by 1H NMR comparison with literature.15b,15c The crude
product was purified by flash column chromatography on silica gel
(PEdEtOAc, 50:1) to give the desired product 3 or 4 as a mixture of
inseparable Z and E-isomers.
131.7, 129.6, 128.0, 117.1, 60.4, 21.4, 14.3 ppm.
4.2.10. Ethyl (E)-3-(4-methoxyphenyl)acrylate (3j).6b 1H NMR (400
MHz, CDCl3)
¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39 (d,
d
J¼16.0 Hz, 1H), 3.84 (s, 3H), 4.25 (q, J¼7.2 Hz, 2H), 1.32 ppm (t,
J¼7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3)
¼167.3, 161.3, 144.2,
d
129.6, 127.2, 115.7, 114.3, 60.3, 55.3, 14.3 ppm.
4.2.11. Ethyl (E)-3-(2-methoxyphenyl)acrylate (3k).15f 1H NMR (400
MHz, CDCl3)
d¼8.01 (d, J¼16.2 Hz,1H), 7.55e7.50 (m, 1H), 7.40e7.33
(m, 1H), 7.02e6.92 (m, 2H), 6.55 (d, J¼16.2 Hz,1H), 4.29 (q, J¼7.1 Hz,
4.2.1. Ethyl (E)-3-(4-chlorophenyl)acrylate (3a).6b 1H NMR (400 MHz,
2H), 3.91 (s, 3H), 1.36 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz,
CDCl3)
d
¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39 (d,
CDCl3)
d
¼167.5, 158.3, 140.0, 131.3, 128.9, 123.4, 120.6, 118.8, 111.1,
J¼16.0 Hz, 1H), 4.25 (q, J¼7.2 Hz, 2H), 1.32 ppm (t, J¼7.2 Hz, 3H); 13
C
60.3, 55.4, 14.3 ppm.
NMR (100 MHz, CDCl3)
60.6, 14.3 ppm.
d¼166.7, 143.1, 136.1, 132.9, 129.1, 129.1, 118.8,
4.2.12. Ethyl (E)-3-(3-methoxyphenyl)acrylate (3l).15f 1H NMR (400
MHz, CDCl3)
d
¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39 (d,
4.2.2. Ethyl (E)-3-(4-fluorophenyl)acrylate (3b).15d 1H NMR (400
J¼16.0 Hz, 1H), 4.25 (q, J¼7.2 Hz, 2H), 1.32 ppm (t, J¼7.2 Hz, 3H); 13
C
MHz, CDCl3)
d
¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39 (d,
NMR (100 MHz, CDCl3)
118.5, 116.1, 112.8, 60.5, 55.2, 14.3 ppm.
d
¼166.9, 159.8, 144.4, 135.8, 129.8, 120.7,
J¼16.0 Hz, 1H), 4.25 (q, J¼7.1 Hz, 2H), 1.32 ppm (t, J¼7.1 Hz, 3H); 13
C
NMR (100 MHz, CDCl3) 13C NMR (100 MHz, CDCl3)
d¼166.8, 163.8 (d,
J¼251.1 Hz), 143.2, 130.7 (d, J¼3.0 Hz), 129.8 (d, J¼8.5 Hz), 118.0 (d,
4.2.13. Ethyl (E)-3-(2-chlorophenyl)acrylate (3m).6b 1H NMR (400
J¼2.3 Hz), 116.0 (d, J¼22.1 Hz), 60.5, 14.3 ppm.
MHz, CDCl3)
d¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39 (d,
J¼16.0 Hz, 1H), 4.25 (q, J¼7.1 Hz, 2H), 1.32 ppm (t, J¼7.1 Hz, 3H); 13
C
4.2.3. Ethyl
(400 MHz, CDCl3)
(E)-3-(4-bromophenyl)acrylate
¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39
(3c).15d 1H NMR
NMR (100 MHz, CDCl3)
d¼166.4, 140.3, 134.9, 132.7, 130.9, 130.1,
d
127.6, 127.0, 120.9, 60.7, 14.3 ppm.
(d, J¼16.0 Hz, 1H), 4.25 (q, J¼7.2 Hz, 2H), 1.32 ppm (t, J¼7.2 Hz, 3H);
13C NMR (100 MHz, CDCl3)
118.9, 60.6, 14.3 ppm.
d¼166.6, 143.1, 133.3, 132.1, 129.4, 124.4,
4.2.14. Ethyl (E)-3-(3-chlorophenyl)acrylate (3n).6b 1H NMR (400
MHz, CDCl3)
d¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39 (d,
J¼16.0 Hz, 1H), 4.25 (q, J¼7.1 Hz, 2H), 1.32 ppm (t, J¼7.1 Hz, 3H); 13
C
4.2.4. Ethyl (E)-3-(4-cyanophenyl)acrylate (3d).15e 1H NMR (400
NMR (100 MHz, CDCl3)
d
¼166.5, 142.9, 136.2, 134.9, 130.1, 130.0,
MHz, CDCl3)
d
¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39 (d,
127.7, 126.2, 119.7, 60.6, 14.3 ppm.
J¼16.0 Hz, 1H), 4.25 (q, J¼7.2 Hz, 2H), 1.32 ppm (t, J¼7.2 Hz, 3H); 13
C
NMR (100 MHz, CDCl3)
118.3, 113.3, 60.9, 14.2 ppm.
d
¼166.1, 142.1, 138.7, 132.6, 128.3, 121.8,
4.2.15. Ethyl (E)-3-(3-bromophenyl)acrylate (3o).15g 1H NMR (400
MHz, CDCl3)
d¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39 (d,
J¼16.0 Hz, 1H), 4.25 (q, J¼7.1 Hz, 2H), 1.32 ppm (t, J¼7.1 Hz, 3H); 13
C
4.2.5. Ethyl (E)-3-(4-nitrophenyl)acrylate (3e).15e 1H NMR (400
NMR (100 MHz, CDCl3)
d¼166.5, 142.8, 136.5, 132.9, 130.7, 130.3,
MHz, CDCl3)
d
¼7.61 (d, J¼16.0 Hz, 1H), 7.49e7.30 (m, 4H), 6.39 (d,
126.6, 123.0, 119.7, 60.6, 14.3 ppm.
J¼16.0 Hz, 1H), 4.25 (q, J¼7.2 Hz, 2H), 1.32 ppm (t, J¼7.2 Hz, 3H); 13
C
NMR (100 MHz, CDCl3)
122.6, 61.0, 14.2 ppm.
d¼166.0, 148.4, 141.6, 140.5, 128.6, 124.1,
4.2.16. Ethyl (E)-3-(2,5-dichlorophenyl)acrylate (3p).15h 1H NMR
(400 MHz, CDCl3)
d¼8.00 (d, J¼16.0 Hz, 1H), 7.59e7.51 (m, 1H),
7.46e7.41 (m, 1H), 7.30e7.22 (m, 1H), 6.41 (d, J¼7.1 Hz, 1H), 4.28 (q,
4.2.6. (E)-Ethyl cinnamate (3f).6b 1H NMR (400 MHz, CDCl3)
d
¼7.71
J¼7.1 Hz, 2H), 1.34 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
(d, J¼16.0 Hz, 1H), 7.59e7.51 (m, 2H), 7.46e7.37 (m, 3H), 6.46 (d,
d
¼166.2, 139.1, 136.2, 135.4, 131.3, 130.0, 128.3, 127.5, 121.3, 60.8,
J¼16.0 Hz, 1H), 4.29 (q, J¼7.2 Hz, 2H), 1.37 ppm (t, J¼7.2 Hz, 3H); 13
C
14.2 ppm.
NMR (100 MHz, CDCl3)
118.2, 60.5, 14.3 ppm.
d
¼167.0, 144.5, 134.4, 130.2, 128.8, 128.0,
4.2.17. Ethyl (E)-3-(3-nitrophenyl)acrylate (3q).15d 1H NMR (400
MHz, CDCl3)
d
¼8.40e8.35 (m, 1H), 8.25e8.19 (m, 1H), 7.84e7.79 (m,
4.2.7. Ethyl (E)-3-(naphthalen-1-yl)acrylate (3g).15d 1H NMR (400
MHz, CDCl3)
1H), 7.71 (d, J¼16.0 Hz, 1H), 7.62e7.54 (m, 1H), 6.56 (d, J¼16.0 Hz,
d
¼8.54 (d, J¼15.8 Hz,1H), 8.26e8.16 (m,1H), 7.95e7.83
1H), 4.29 (q, J¼7.1 Hz, 2H), 1.35 ppm (t, J¼7.1 Hz, 3H); 13C NMR
(m, 2H), 7.80e7.71 (m, 1H), 7.64e7.44 (m, 3H), 6.54 (d, J¼15.8 Hz,
(100 MHz, CDCl3)
d¼166.1, 148.7, 141.6, 136.2, 133.6, 129.9, 124.4,
1H), 4.33 (q, J¼7.1 Hz, 2H), 1.39 ppm (t, J¼7.1 Hz, 3H); 13C NMR
122.4, 121.4, 60.9, 14.2 ppm.
(100 MHz, CDCl3)
126.8, 126.2, 125.4, 125.0, 123.4, 120.9, 60.6, 14.4 ppm.
d
¼166.9, 141.6, 133.6, 131.8, 131.4, 130.4, 128.7,
4.2.18. Ethyl (E)-3-(2-nitrophenyl)acrylate (3r).15d 1H NMR (400
MHz, CDCl3)
d
¼8.09 (d, J¼15.8 Hz, 1H), 8.05e7.99 (m, 1H),
4.2.8. Ethyl (E)-3-(naphthalen-2-yl)acrylate (3h).15d 1H NMR (400
7.67e7.60 (m, 2H), 7.57e7.49 (m, 1H), 6.35 (d, J¼15.8 Hz, 1H), 4.27
MHz, CDCl3)
d¼7.97e7.91 (m, 1H), 7.90e7.79 (m, 4H), 7.71e7.62 (m,
(q, J¼7.1 Hz, 2H), 1.33 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz,

476
Y. Wang et al. / Tetrahedron 72 (2016) 472e478
CDCl3)
60.9, 14.2 ppm.
d
¼165.7, 148.3, 139.8, 133.5, 130.6, 130.2, 129.1, 124.8, 123.3,
7.94e7.82 (m, 2H), 7.70 (d, J¼33.1 Hz, 1H), 7.63e7.48 (m, 3H), ppm
4.42 (q, J¼7.1 Hz, 2H), 1.44 (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz,
CDCl3)
d
¼161.4 (d, J¼34.5 Hz), 147.8 (d, J¼268.8 Hz), 133.6, 131.4,
4.2.19. Ethyl (E)-3-(furan-2-yl)acrylate (3s).15h 1H NMR (400 MHz,
CDCl3)
130.0 (d, J¼1.8 Hz), 128.8, 128.8, 128.7, 127.0 (d, J¼4.0 Hz), 126.1,
d
¼7.49e7.46 (m, 1H), 7.42 (d, J¼16.0 Hz, 1H), 6.61e6.58 (m,
125.4, 123.4, 113.8 (d, J¼5.5 Hz), 62.0, 14.2 ppm.
1H), 6.48e6.45 (m, 1H), 6.31 (d, J¼15.7 Hz, 1H), 4.24 (q, J¼7.1 Hz,
2H), 1.32 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
d¼167.0,
4.2.29. Ethyl (Z)-2-fluoro-3-(naphthalen-2-yl)acrylate (4e).6a 1H
150.9, 144.6, 130.9, 115.9, 114.5, 112.2, 60.4, 14.3 ppm.
NMR (400 MHz, CDCl3)
d
¼8.15e8.07 (m, 1H), 7.92e7.75 (m, 4H),
7.58e7.46 (m, 2H), 7.09 (d, J¼35.2 Hz, 1H), 4.38 (q, J¼7.1 Hz, 2H),
4.2.20. Ethyl (E)-3-(thiophen-2-yl)acrylate (3t).15i 1H NMR (400
MHz, CDCl3)
¼7.80 (d, J¼15.7 Hz, 1H), 7.43e7.35 (m, 1H), 7.30e7.24
1.41 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
¼161.4 (d,
d
d
J¼34.2 Hz), 147.1 (d, J¼267.8 Hz), 133.6 (d, J¼2.1 Hz), 133.1, 130.7 (d,
J¼8.1 Hz), 128.7 (d, J¼4.7 Hz), 128.6, 128.5, 127.6, 127.2, 126.8 (d,
J¼8.4 Hz), 126.5, 117.6 (d, J¼4.7 Hz), 61.9, 14.2 ppm.
(m, 1H), 7.11e7.02 (m, 1H), 6.26 (d, J¼15.7 Hz, 1H), 4.27 (q, J¼7.1 Hz,
2H), 1.35 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
¼166.8,
d
139.6, 137.0, 130.8, 128.3, 128.0, 117.0, 60.4, 14.3 ppm.
4.2.30. Ethyl (Z)-2-fluoro-3-(p-tolyl)acrylate (4f).15c 1H NMR
4.2.21. Ethyl (2E,4E)-5-phenylpenta-2,4-dienoate (3u).15e 1H NMR
(400 MHz, CDCl3)
¼7.51e7.40 (m, 3H), 7.39e7.27 (m, 3H),
(400 MHz, CDCl3)
d
¼7.64e7.54 (m, 2H), 7.28e7.17 (m, 2H), 6.92
d
(d, J¼35.5 Hz, 1H), 4.37 (q, J¼7.1 Hz, 2H), 2.40 (s, 3H), 1.40 ppm
6.94e6.82 (m, 2H), 5.99 (d, J¼15.3 Hz, 1H), 4.23 (q, J¼7.1 Hz, 2H),
(t, J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
d
¼161.5 (d,
1.32 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
d¼167.0,
J¼34.1 Hz), 146.5 (d, J¼266.0 Hz), 140.0 (d, J¼2.9 Hz), 130.2 (d,
J¼8.1 Hz), 129.5, 128.3 (d, J¼4.4 Hz), 117.5 (d, J¼4.8 Hz), 61.7,
21.4, 14.2 ppm.
144.5, 140.3, 136.0, 129.0, 128.8, 127.2, 126.2, 121.3, 60.3, 14.3 ppm.
4.2.22. Ethyl (E)-5-phenylpent-2-enoate (3v).15j 1H NMR (400 MHz,
CDCl3)
d
¼7.33e7.27 (m, 2H), 7.24e7.16 (m, 3H), 7.06e6.93 (m, 1H),
4.2.31. Ethyl (Z)-2-fluoro-3-(4-methoxyphenyl)acrylate (4g).15c 1H
5.85 (dt, J¼15.7, 1.6 Hz, 1H), 4.18 (q, J¼7.1 Hz, 2H), 2.83e2.73 (m,
NMR (400 MHz, CDCl3)
d
¼7.78e7.48 (m, 2H), 7.01e6.80 (m, 3H),
2H), 2.59e2.46 (m, 2H), 1.28 ppm (t, J¼7.1 Hz, 3H); 13C NMR
4.36 (q, J¼7.1 Hz, 2H), 3.85 (s, 3H), 1.39 ppm (t, J¼7.1 Hz, 3H); 13C
(100 MHz, CDCl3)
d
¼166.6, 148.0, 140.8, 128.4, 128.3, 126.1, 121.8,
NMR (100 MHz, CDCl3)
d
¼161.6 (d, J¼33.9 Hz), 160.6, 145.8 (d,
60.2, 34.3, 33.9, 14.2 ppm.
J¼263.8 Hz), 132.0 (d, J¼8.4 Hz), 123.8, 117.3 (d, J¼5.0 Hz), 114.2,
61.6, 55.3, 14.2 ppm.
4.2.23. Ethyl (E)-3-cyclohexylacrylate (3w).6b 1H NMR (400 MHz,
CDCl3)
d¼6.91 (dd, J¼15.8, 6.8 Hz, 1H), 5.75 (dd, J¼15.8, 1.5 Hz, 1H),
4.2.32. Ethyl (Z)-2-fluoro-3-(2-methoxyphenyl)acrylate (4h).15k 1H
4.18 (q, J¼7.1 Hz, 2H), 2.19e2.06 (m, 1H), 1.82e1.71 (m, 4H),
NMR (400 MHz, CDCl3)
7.05e6.86 (m, 2H), 4.42e4.29 (m, 2H), 3.92e3.82 (m, 3H),
1.45e1.31 ppm (m, 3H); 13C NMR (100 MHz, CDCl3)
d
¼7.95e7.84 (m, 1H), 7.49e7.30 (m, 2H),
1.71e1.63 (m, 1H), 1.38e1.06 ppm (m, 8H); 13C NMR (100 MHz,
CDCl3)
d
¼167.1, 154.3, 118.8, 60.1, 40.4, 31.6, 25.9, 25.7, 14.2 ppm.
d
¼161.6 (d,
J¼34.8 Hz), 157.3 (d, J¼1.7 Hz), 146.9 (d, J¼266.0 Hz), 130.9 (d,
J¼14.1 Hz), 120.7, 120.0 (d, J¼4.8 Hz), 111.2 (d, J¼3.2 Hz), 110.6, 61.7,
55.6, 14.2 ppm.
4.2.24. Ethyl (E)-4,4,4-trifluoro-3-phenylbut-2-enoate (3x).15h 1H
NMR (400 MHz, CDCl3) ¼7.46e7.37 (m, 3H), 7.33e7.27 (m, 2H),
6.61 (q, J¼1.4 Hz, 1H), 4.04 (q, J¼7.1 Hz, 2H), 1.06 ppm (t, J¼7.1 Hz,
3H); 13C NMR (100 MHz, CDCl3)
d
d¼164.1, 142.3 (q, J¼30.9 Hz), 131.0,
4.2.33. Ethyl (Z)-2-fluoro-3-(3-methoxyphenyl)acrylate (4i).15l 1H
129.3, 128.6, 128.1, 124.5 (q, J¼5.4 Hz), 122.5 (q, J¼274.8 Hz), 61.0,
NMR (400 MHz, CDCl3)
d
¼7.35e7.28 (m, 1H), 7.25e7.19 (m, 2H),
13.7 ppm.
6.96e6.83 (m, 2H), 4.35 (q, J¼7.1 Hz, 2H), 3.83 (s, 3H), 1.38 ppm (t,
J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
¼161.38 (d, J¼34.2 Hz),
d
4.2.25. Ethyl (Z)-3-(4-chlorophenyl)-2-fluoroacrylate (4a).15c 1H
NMR (400 MHz, CDCl3)
6.90 (d, J¼34.7 Hz, 1H), 4.38 (q, J¼7.1 Hz, 2H), 1.41 ppm (t, J¼7.1 Hz,
3H); 13C NMR (100 MHz, CDCl3)
J¼268.7 Hz), 135.6 (d, J¼3.9 Hz), 131.4 (d, J¼8.3 Hz), 129.6 (d,
J¼4.4 Hz), 129.1, 116.2 (d, J¼4.8 Hz), 62.0, 14.2 ppm.
159.6, 147.1 (d, J¼268.1 Hz), 132.3 (d, J¼4.4 Hz), 129.7, 122.9 (d,
J¼7.7 Hz), 117.4 (d, J¼4.5 Hz), 115.7 (d, J¼2.6 Hz), 115.1 (d, J¼8.8 Hz),
61.9, 55.2, 14.2 ppm.
d¼7.63e7.56 (m, 2H), 7.43e7.36 (m, 2H),
d
¼161.1 (d, J¼34.3 Hz), 147.2 (d,
4.2.34. Ethyl (Z)-3-(2-chlorophenyl)-2-fluoroacrylate (4j).6a 1H
NMR (400 MHz, CDCl3)
d
¼7.94e7.88 (m, 1H), 7.46e7.27 (m, 4H),
4.37 (q, J¼7.1 Hz, 2H),1.39 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz,
4.2.26. Ethyl (Z)-2-fluoro-3-(4-fluorophenyl)acrylate (4b).15c 1H
NMR (400 MHz, CDCl3)
6.88 (d, J¼34.9 Hz, 2H), 4.35 (q, J¼7.1 Hz, 2H), 1.38 ppm (t, J¼7.1 Hz,
3H); 13C NMR (100 MHz, CDCl3)
(d, J¼34.1 Hz), 146.7 (dd, J¼267.2, 2.7 Hz), 132.2 (t, J¼8.4 Hz), 127.3
(dd, J¼4.4, 3.4 Hz), 116.3 (dd, J¼4.9, 0.9 Hz), 115.9 (d, J¼21.8 Hz),
61.9, 14.2 ppm.
CDCl3)
d
¼161.0 (d, J¼34.9 Hz), 147.8 (d, J¼270.4 Hz), 134.3 (d,
d
¼7.69e7.59 (m, 2H), 7.15e7.03 (m, 2H),
J¼2.0 Hz), 131.3, 131.1, 130.5 (d, J¼2.1 Hz), 129.2 (d, J¼4.9 Hz), 127.0,
112.9 (d, J¼3.3 Hz), 62.1, 14.2 ppm.
d
¼163.2 (dd, J¼251.5, 4.0 Hz), 161.3
4.2.35. Ethyl (Z)-3-(3-chlorophenyl)-2-fluoroacrylate (4k).6a 1H
NMR (400 MHz, CDCl3)
d
¼7.68e7.62 (m, 1H), 7.54e7.48 (m, 1H),
7.39e7.32 (m, 2H), 6.86 (d, J¼34.3 Hz, 1H), 4.36 (q, J¼7.1 Hz, 2H),
1.39 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
¼161.0 (d,
d
4.2.27. Ethyl (Z)-2-fluoro-3-phenylacrylate (4c).6a 1H NMR (400
J¼34.3 Hz), 147.7 (d, J¼270.3 Hz), 134.7, 132.8 (d, J¼4.4 Hz), 130.0 (d,
J¼2.3 Hz), 129.9 (d, J¼5.7 Hz), 129.6 (d, J¼2.6 Hz), 128.2 (d,
J¼8.1 Hz), 116.0 (d, J¼4.6 Hz), 62.1, 14.2 ppm.
MHz, CDCl3)
d
¼7.70e7.62 (m, 2H), 7.45e7.33 (m, 3H), 6.92 (d,
J¼35.2 Hz, 1H), 4.36 (q, J¼7.1 Hz, 2H), 1.39 ppm (t, J¼7.1 Hz, 3H); 13
C
NMR (100 MHz, CDCl3)
d¼161.4 (d, J¼34.2 Hz),147.0 (d, J¼267.7 Hz),
131.1 (d, J¼4.4 Hz), 130.3 (d, J¼8.1 Hz), 129.6 (d, J¼2.8 Hz), 128.8,
117.4 (d, J¼4.7 Hz), 61.9, 14.2 ppm.
4.2.36. Ethyl (Z)-3-(2,4-dichlorophenyl)-2-fluoroacrylate (4l).15n 1H
NMR (400 MHz, CDCl3)
d
¼7.85 (t, J¼6.5 Hz, 1H), 7.48e7.45 (m, 1H),
7.33e7.28 (m, 1H), 7.29 (d, J¼34.3 Hz, 1H), 4.37 (q, J¼7.1 Hz, 2H),
4.2.28. Ethyl (Z)-2-fluoro-3-(naphthalen-1-yl)acrylate (4d).15c 1H
NMR (400 MHz, CDCl3)
1.39 ppm (t, J¼7.1, 3.7 Hz, 3H); 13C NMR (100 MHz, CDCl3)
¼160.8
d
d
¼8.14e8.05 (m, 1H), 8.03e7.95 (m, 1H),
(d, J¼34.7 Hz), 148.1 (d, J¼271.5 Hz), 135.8 (d, J¼3.1 Hz), 135.0 (d,

Y. Wang et al. / Tetrahedron 72 (2016) 472e478
477
5. For recent examples on Peterson reaction (a) Hamlin, T. A.; Kelly, C. B.; Cywar,
R. M.; Leadbeater, N. E. J. Org. Chem. 2014, 79, 1145e1155; (b) Beveridge, R. E.;
Batey, R. A. Org. Lett. 2013, 15, 3086; (c) Hamlin, T. A.; Lazarus, G. M. L.; Kelly, C.
B.; Leadbeater, N. E. Org. Process Res. Dev. 2014, 18, 1253; (d) Iqbal, M.; Duffy, P.;
J¼2.0 Hz), 131.8 (d, J¼14.2 Hz), 129.7, 127.8 (d, J¼5.0 Hz), 127.5, 111.9
(d, J¼3.3 Hz), 62.2, 14.1 ppm.
4.2.37. Ethyl (Z)-3-(benzo[d]1,3 dioxol-5-yl)-2-fluoroacrylate
ꢀ
Evans, P.; Cloughley, G.; Allan, B.; Lledo, A.; Verdaguer, X.; Riera, A. Org. Biomol.
(4m).15m 1H NMR (400 MHz, CDCl3)
d
¼7.25e7.21 (m, 1H),
Chem. 2008, 6, 4649; (e) Neubauer, T.; Kammerer-Pentierz, C.; Bach, T. Chem.
Commun. 2012, 11629; (f) Motomatsu, D.; Ishida, S.; Ohno, K.; Iwamoto, T. Chem.
dEur. J. 2014, 20, 9424; (g) Assadi, N.; Pogodin, S.; Agranat, I. Eur. J. Org. Chem.
2011, 6773; (h) Sautier, B.; Collins, K. D.; Procter, D. J. Beilstein J. Org. Chem. 2013,
9, 1443; (i) Inoue, S.; Ichinohe, M.; Sekiguchi, A. Angew. Chem., Int. Ed. 2007, 46,
3346; (j) Izod, K.; McFarlane, W.; Tyson, B. V. Eur. J. Org. Chem. 2004, 1043; (k)
Fu1rstner, A.; Brehm, C.; Cancho-Grande, Y. Org. Lett. 2001, 3, 3955; (l) Murai, T.;
Fujishima, A.; Iwamoto, C.; Kato, S. J. Org. Chem. 2003, 68, 7979; (m) Iguchi, M.;
Tomioka, K. Org. Lett. 2002, 4, 4329; (n) Perales, J. B.; Makino, N. F.; Van
Vranken, D. L. J. Org. Chem. 2002, 67, 6711; (o) Aubele, D. L.; Wan, S.; Floreancig,
P. E. Angew. Chem., Int. Ed. 2005, 44, 3485; (p) Halton, B.; Boese, R.; Dixon, G. M.
Eur. J. Org. Chem. 2003, 4507.
7.10e7.03 (m, 1H), 6.89e6.77 (m, 2H), 6.00 (s, 2H), 4.33 (q, J¼7.1 Hz,
2H), 1.37 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
¼161.5
d
(d, J¼33.9 Hz), 148.8 (d, J¼3.5 Hz), 148.1, 145.9 (d, J¼265.1 Hz), 125.7
(d, J¼6.8 Hz), 125.2 (d, J¼4.5 Hz), 117.4 (d, J¼4.6 Hz), 109.7 (d,
J¼10.7 Hz), 108.5, 101.5, 61.7, 14.2 ppm.
4.2.38. Ethyl (Z)-2-fluoro-3-(furan-2-yl)acrylate (4n).15c 1H NMR
(400 MHz, CDCl3)
d
¼7.56e7.49 (m, 1H), 6.94 (d, J¼33.4 Hz, 1H),
6. (a) Michida, M.; Mukaiyama, T. Chem. Lett. 2008, 37, 890; (b) Michida, M.;
Mukaiyama, T. Chem. Lett. 2008, 37, 704; (c) Welch, J. T.; Gregor, T.; Kornilov, A.
Isr. J. Chem. 1999, 35, 171; (d) Dicker, I. B. J. Org. Chem. 1993, 58, 2324; (e)
Matsuda, I.; Murata, S.; Izumi, Y. J. Org. Chem. 1980, 45, 237; (f) Matsuda, I. J.
Organomet. Chem. 1987, 321, 307; (g) Pellon, P.; Ko, Y. L.; Cosquer, P.; Hamelin, J.;
6.88e6.84 (m, 1H), 6.55e6.49 (m, 1H), 4.33 (q, J¼7.1 Hz, 1H),
1.36 ppm (t, J¼7.1 Hz, 2H); 13C NMR (100 MHz, CDCl3)
¼161.0 (d,
d
J¼32.9 Hz), 146.8 (d, J¼4.4 Hz), 145.1 (d, J¼266.5 Hz), 144.2 (d,
J¼3.8 Hz), 115.3 (d, J¼11.1 Hz), 112.5, 107.2 (d, J¼8.1 Hz), 61.8,
14.2 ppm.
ꢀ
Carrie, R. Tetrahedron Lett. 1986, 27, 4299.
7. For selected recent reviews of NHCs-catalysis, see (a) Enders, D.; Niemeier, O.;
Henseler, A. Chem. Rev. 2007, 107, 5606; (b) Biju, A. T.; Kuhl, N.; Glorius, F. Acc.
Chem. Res. 2011, 44, 1182; (c) Mahatthananchai, J.; Bode, J. W. Chem. Sci. 2012, 3,
192; (d) Grossmann, A.; Enders, D. Angew. Chem., Int. Ed. 2012, 51, 314; (e)
Hopkinson, N.; Richter, C.; Schedler, M.; Glorius, F. Nature 2014, 510, 485; (f)
Menon, R. S.; Biju, A. T.; Nair, V. Chem. Soc. Rev. 2015, 44, 5040; (g) Flanigan, D.
M.; Romanov-Michailidis, F.; White, N. A.; Rovis, T. Chem. Rev. 2015, 115, 9307;
(h) Douglas, J.; Churchill, G.; Smith, A. D. Synthesis 2012, 44, 2295; (i) Ryan, S. J.;
Candish, L.; Lupton, D. W. Chem. Rev. 2013, 42, 4906; (j) Izquierdo, J.; Hutson, G.
E.; Cohen, D. T.; Scheidt, K. A. Angew. Chem., Int. Ed. 2012, 51, 11686.
8. For selected examples, see (a) Burstein, C.; Glorius, F. Angew. Chem., Int. Ed.
2004, 43, 6205; (b) Sohn, S. S.; Rosen, E. L.; Bode, J. W. J. Am. Chem. Soc. 2004,
126, 14370; (c) Nair, V.; Vellalath, S.; Poonoth, M.; Suresh, E. J. Am. Chem. Soc.
2006, 128, 8736; (d) Vora, H. U.; Rovis, T. J. Am. Chem. Soc. 2010, 132, 2860; (e)
Mahatthananchai, J.; Zheng, P.; Bode, J. W. Angew. Chem., Int. Ed. 2011, 50, 1673;
(f) Mo, J.; Chen, X.; Chi, Y. J. Am. Chem. Soc. 2012, 134, 8810; (g) Izquierdo, J.;
Scheidt, K. A. J. Am. Chem. Soc. 2013, 135, 10634; (h) Raup, D. E. A.; Cardinal-
David, B.; Holte, D.; Scheidt, K. A. Nat. Chem. 2010, 2, 766; (i) Wheeler, P.; Vora,
H. U.; Rovis, T. Chem. Sci. 2013, 4, 1674; (j) Zhang, B.; Feng, P.; Cui, Y. X.; Jiao, N.
Chem. Commun. 2012, 7280; (k) Chen, X.; Fang, X.; Chi, Y. R. Chem. Sci. 2013, 4,
2613; (l) Sun, L.-H.; Liang, Z.-Q.; Jia, W.-Q.; Ye, S. Angew. Chem., Int. Ed. 2013, 52,
5803; (m) Wu, K.-J.; Li, G.-Q.; Li, Y.; Dai, L.-X.; You, S.-L. Chem. Commun. 2011,
493; (n) Li, G.-Q.; Dai, L.-X.; You, S.-L. Chem. Commun. 2007, 852.
4.2.39. Ethyl (Z)-2-fluoro-3-(thiophen-2-yl)acrylate (4o).15c 1H NMR
(400 MHz, CDCl3)
d
¼7.51 (d, J¼5.1 Hz, 1H), 7.35 (d, J¼4.1 Hz, 1H),
7.20 (d, J¼33.9 Hz, 1H), 7.12e7.07 (m, 1H), 4.34 (q, J¼7.1 Hz, 2H),
1.37 ppm (t, J¼7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3)
¼161.0 (d,
d
J¼32.9 Hz), 145.4 (d, J¼265.4 Hz), 133.5 (d, J¼5.7 Hz), 131.2 (d,
J¼4.9 Hz), 130.1 (d, J¼9.8 Hz), 127.4, 111.9 (d, J¼8.9 Hz), 99.9, 61.8,
14.2 ppm.
4.2.40. Ethyl (Z)-2-fluoro-5-phenylpent-2-enoate (4p).15c 1H NMR
(400 MHz, CDCl3)
d
¼7.34e7.28 (m, 2H), 7.25e7.18 (m, 3H), 6.14 (dt,
J¼33.1, 7.7 Hz, 1H), 4.27 (q, J¼7.1 Hz, 2H), 2.83e2.73 (m, 2H), 2.57
(qd, J¼7.7, 2.2 Hz, 2H), 1.32 ppm (t, J¼7.1 Hz, 3H); 13C NMR
(100 MHz, CDCl3)
d
¼160.77 (d, J¼35.5 Hz), 148.1 (d, J¼256.6 Hz),
140.5, 128.5, 128.3, 126.2, 119.5 (d, J¼11.6 Hz), 61.5, 34.4 (d,
J¼2.0 Hz), 25.9 (d, J¼2.4 Hz), 14.1 ppm.
9. For selected examples, see (a) He, L.; Guo, H.; Li, Y. Z.; Du, G. F.; Dai, B. Chem.
Commun. 2014, 3719; (b) Fu, Z.; Xu, J.; Zhu, T.; Leong, W. W. Y.; Chi, Y. R. Nat.
Chem. 2013, 5, 835; (c) Chauhan, P.; Enders, D. Angew. Chem., Int. Ed. 2014, 53,
1485; (d) Bugaut, X.; Liu, F.; Glorius, F. J. Am. Chem. Soc. 2011, 133, 8130; (e)
Hovey, M. T.; Check, C. T.; Sipher, A. F.; Scheidt, K. A. Angew. Chem., Int. Ed. 2014,
9603; (f) Chen, X.; Gao, Z.; Song, C.; Zhang, C.; Wang, Z.; Ye, S. Angew. Chem., Int.
Ed. 2014, 53, 11611; (g) Li, F.; Wu, Z.; Wang, J. Angew. Chem., Int. Ed. 2015, 54,
656; (h) Dong, X.; Yang, W.; Hu, W.; Sun, J. Angew. Chem., Int. Ed. 2015, 54, 660;
(i) Wu, Z.; Li, F.; Wang, J. Angew. Chem., Int. Ed. 2015, 54, 1629; (j) Li, Y.-Z.; Wang,
Y.; Du, G.-F.; Zhang, H.-Y.; Yang, H.-L.; He, L. Asian J. Org. Chem. 2015, 4, 327; (k)
Chen, J.-A.; Meng, S.-X.; Wang, L.-M.; Tang, H.-M.; Huang, Y. Chem. Sci. 2015, 6,
4184; (l) Guo, H.; Wang, Y.; Du, G.-F.; Dai, B.; He, L. Tetrahedron 2015, 71, 3472;
Acknowledgements
This work was supported by the National Natural Science Foun-
dation of China (Nos. 21262027, 21428302) and the Outstanding
Young Scientist program of Shihezi University (No. 2012ZRKXJQ06).
Supplementary data
Supplementary data associated with this article can be found in
the online version, at http://dx.doi.org/10.1016/j.tet.2015.11.043.
^
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(m) Pan, X.-C.; Lacote, E.; Lalevee, J.; Curran, D. P. J. Am. Chem. Soc. 2012, 134,
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5669; (n) Pan, X.-C.; Boussonniere, A.; Curran, D. P. J. Am. Chem. Soc. 2013, 135,
14433; (o) Pan, X.-C.; Vallet, A. L.; Schweizer, S.; Dahbi, K.; Delpech, B.; Blan-
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chard, N.; Graff, B.; Geib, S. J.; Curran, D. P.; Lalevee, J.; Lacote, E. J. Am. Chem. Soc.
2013, 135, 10484.
References and notes
10. For reviews, see (a) He, L.; Guo, H.; Wang, Y.; Du, G.-F.; Dai, B. Tetrahedron Lett.
2015, 56, 972; (b) Fuchter, M. J. Chem.dEur. J. 2010, 16, 12286.
1. For selected reviews, see (a) Gao, B.; Zhao, Y.; Hu, J.-Y.; Hu, J.-B. Org. Chem. Front.
2015, 2, 163; (b) Kirsch, P. Modern Fluoroorganic Chemistry: Synthesis, Reactivity,
Applications, second ed..; Wiley-VCH: Weinheim, 2013; (c) Hu, J.-B.; Zhang, W.;
Wang, F. Chem. Commun. 2009, 7465; (d) Uneyama, K. Organofluorine Chemistry;
Blackwell: Oxford, 2006; (e) Chambers, R. D. Organofluorine Chemistry: Fluori-
nated Alkenes and Reactive Intermediates; Springer: New York, 1997.
11. For NHCs-catalysed cyanation reactions, see (a) Song, J. J.; Gallou, F.; Reeves, J.
T.; Tan, Z.; Yee, N. K.; Senanayake, C. H. J. Org. Chem. 2006, 71, 1273; (b) Fukuda,
Y.; Maeda, Y.; Ishii, S.; Kondo, K.; Aoyama, T. Synthesis 2006, 2006, 589; (c)
Suzuki, Y.; Bakar, M.; Muramatsu, K.; Sato, M. Tetrahedron 2006, 62, 4227; (d)
Tan, M.; Zhang, Y.; Ying, J. Y. Adv. Synth. Catal. 2009, 351, 1390.
€
2. (a) Allmendinger, T.; Furet, P.; Hungerbuhler, E. Tetrahedron Lett. 1990, 31, 7297;
12. (a) Song, J. J.; Tan, Z.; Reeves, J. T.; Gallou, F.; Yee, N. K.; Senanayake, C. H. Org.
Lett. 2005, 7, 2193; (b) Song, J. J.; Tan, Z.; Reeves, J. T.; Yee, N. K.; Senanayake, C.
H. Org. Lett. 2007, 9, 1013; (c) Du, G.-F.; He, L.; Gu, C.-Z.; Dai, B. Synlett 2010,
2513; (d) Cai, Z.-H.; Du, G. F.; He, L.; Gu, C.-Z.; Dai, B. Synthesis 2011, 2011, 2073;
(e) Wu, J.; Sun, X.; Ye, S.; Sun, W. Tetrahedron Lett. 2006, 47, 4813; (f) Zou, X.-L.;
Du, G. F.; Sun, W.-F.; He, L.; Ma, X.-W.; Gu, C.-Z.; Dai, B. Tetrahedron 2013, 69,
607; (g) Fan, Y.-C.; Du, G. F.; Sun, W.-F.; Kang, W.; He, L. Tetrahedron Lett. 2012,
53, 2231; (h) Du, G.-F.; Xing, F.; Gu, C.-Z.; Dai, B.; He, L. RSC Adv. 2015, 5, 35513.
13. (a) Raynaud, J.; Ciolino, A.; Baceiredo, A.; Destarac, M.; Bonnette, F.; Kato, T.;
Gnanou, Y.; Taton, D. Angew. Chem., Int. Ed. 2008, 47, 5390; (b) Raynaud, J.; Liu,
N.; Gnanou, Y.; Taton, D. Macromolecules 2010, 43, 8853; (c) Raynaud, J.; Liu, N.;
€
(b) Allmendinger, T.; Felder, E.; Hungerbuhler, E. Tetrahedron Lett. 1990, 31,
7301; (c) Zhao, K.; Lim, D. S.; Funaki, T.; Welch, J. T. Bioorg. Med. Chem. 2003, 11,
207; (d) Bartlett, P. A.; Otake, A. J. Org. Chem. 1995, 60, 3107.
3. (a) Welch, J. T.; Lin, J.; Boros, L. G.; DeCorte, B.; Bergmann, K.; Gimi, R. In Bio-
medical Frontiers of Fluorine Chemistry; Ojima, I., McCarthy, J. R., Welch, J. T.,
Eds.; American Chemical Society: Washington DC, 1996; p 129; (b) Boros, L. G.;
DeCorte, B.; Gimi, R. H.; Welch, J. T.; Wu, Y.; Handschumacher, R. Tetrahedron
Lett. 1994, 33, 6033; (c) Welch, J. T.; Lin, J. Tetrahedron 1996, 52, 291.
4. (a) Peterson, D. J. J. Org. Chem. 1968, 33, 780 For reviews on Peterson elimi-
nations, see; (b) Ager, D. J. Org. React. 1990, 38, 1; (c) Barrett, A. G. M.; Hill, J. M.;
Wallace, E. M.; Flygare, J. A. Synlett 1991, 764; (d) Kawashima, T.; Okazaki, R.
Synlett 1996, 600; (e) van Staden, L. F.; Gravestock, D.; Ager, D. J. Chem. Soc. Rev.
2002, 31, 195; (f) Ager, D. J. Sci. Synth. 2010, 47a, 85; (g) Kano, N.; Kawashima, T.
Modern Carbonyl Olefination; Wiley-VCH: Weinheim, 2004; p 18; (h) Wang, Z.
Comprehensive Organic Name Reactions and Reagents; Wiley, 2000, Vol. 2,
p 2176.
ꢁ
Fevre, M.; Gnanou, Y.; Taton, D. Polym. Chem. 2011, 2, 1706; (d) Lohmeijer, B. G.;
Dubois, G.; Leibfarth, F.; Pratt, R. C.; Nederberg, F.; Nelson, A.; Waymouth, R. M.;
Wade, C.; Hedrick, J. L. Org. Lett. 2006, 8, 4683; (e) Brown, H. A.; Chang, Y. A.;
Waymouth, R. M. J. Am. Chem. Soc. 2013, 135, 18738.
14. Arduengo, A. J., III; Krafczyk, R.; Schmutzler, R. Tetrahedron 1999, 55, 14523.

478
Y. Wang et al. / Tetrahedron 72 (2016) 472e478
15. (a) Kerr, M. S.; de Alaniz, J. R.; Rovis, T. J. Org. Chem. 2005, 70, 5725; (b) Huang,
W.; Zhao, S.-H.; Xu, N. Synthesis 2015, 47, 359; (c) Qian, J.; Yi, W.; Lv, M.; Cai, C.
Synlett 2015, 127; (d) Su, Y.-H.; Wu, Z.; Tian, S.-K. Chem. Commun. 2013, 49,
6528; (e) Leung, P. S.-W.; Teng, Y.; Toy, P. H. Org. Lett. 2010, 12, 4996; (f) Wang,
Y.; Luo, J.; Liu, Z. J. Organomet. Chem. 2013, 739, 1; (g) Bera, R.; Dhananjaya, G.;
Singh, S. N.; Kumar, R.; Mukkanti, K.; Pal, M. Tetrahedron 2009, 65, 1300; (h)
Wang, P.; Liu, C.-R.; Sun, X.-L.; Chen, S.-S.; Li, J.-F.; Xie, Z.; Tang, Y. Chem.
Commun. 2012, 290; (i) Wadhwa, K.; Verkade, J. G. J. Org. Chem. 2009, 74, 4368;
(j) Webb, D.; Jamison, T. F. Org. Lett. 2012, 14, 2465; (k) Chintareddy, V. R.; Ellern,
A.; Verkade, J. G. J. Org. Chem. 2010, 75, 7166; (l) Pfund, E.; Lebargy, C.; Rouden,
J.; Lequeux, T. J. Org. Chem. 2007, 72, 7871; (m) Ren, A.; Yang, X.; Hong, J.; Yu, X.
Synlett 2008, 2376; (n) Germany Pat, WO1998027049 A1.