Synthesis of (E)-α,β-Unsaturated Carbonyls via Silver-Catalyzed Tandem Epoxide Rearrangement/Intermolecular Carbonyl- Heteroalkyne Metathesis

Article abstract of DOI:10.1002/adsc.201600623

A regio- and stereoselective method for the synthesis of (E)-α,β-unsaturated carbonyls has been developed via a silver-catalyzed tandem epoxide rearrangement/intermolecular carbonyl-heteroalkyne metathesis. Various heteroalkynes including ynol ethers, ynamides, and thioalkynes work well for this transformation, leading to the production of (E)-α,β-unsaturated esters, amides, and thioesters in moderate to excellent yields with good functional group compatibility. It represents one of the rare examples of regio- and stereoselective intermolecular alkyne-carbonyl metathesis (ACM). (Figure presented.).

Full text of DOI:10.1002/adsc.201600623

COMMUNICATIONS
DOI: 10.1002/adsc.201600623
Synthesis of (E)-a,b-Unsaturated Carbonyls via Silver-Catalyzed
Tandem Epoxide Rearrangement/Intermolecular Carbonyl-
Heteroalkyne Metathesis
Hui Zhu,a Weiwei Jin,a Jiayao He,a Yan Zhang,a,* and Gangguo Zhua,*
a
Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua 321004, Peopleꢀs Republic of China
Fax : (+86)-579-8228-2269; phone: (+86)-579-8228-2640; e-mail: zhangyan001@zjnu.edu.cn or gangguo@zjnu.cn
Received: June 15, 2016; Revised: September 2, 2016; Published online: && &&, 0000
Supporting information for this article can be found under: http://dx.doi.org/10.1002/adsc.201600623.
Abstract: A regio- and stereoselective method for
the synthesis of (E)-a,b-unsaturated carbonyls has
been developed via a silver-catalyzed tandem epox-
ide rearrangement/intermolecular carbonyl-hetero-
alkyne metathesis. Various heteroalkynes including
ynol ethers, ynamides, and thioalkynes work well
for this transformation, leading to the production of
(E)-a,b-unsaturated esters, amides, and thioesters in
moderate to excellent yields with good functional
group compatibility. It represents one of the rare
examples of regio- and stereoselective intermolecu-
lar alkyne-carbonyl metathesis (ACM).
In this respect, Ochiai and co-workers reported
a one-pot synthesis of conjugated enones via the di-
fluoro-l3-bromane-induced oxidative coupling of pri-
mary alcohols with alkynes, but under harsh reaction
conditions and with limited substrate scope
[Eq. (2)].[7] Recently, a well-designed protocol for the
construction of medium and large ring lactones has
been achieved by the group of Li and Sun using the
ACM reaction of ynol ethers with cyclic oxocarbeni-
ums, generated in situ from the BF3·OEt2-mediated
elimination of acetals [Eq. (3)].[8] On the other hand,
Keywords: [2+2] cycloaddition; epoxides; silver;
a,b-unsaturated carbonyl compounds; ynamides;
ynol ethers
Constructing carbon-carbon bonds is at the heart of
synthetic organic chemistry. Among the vast number
of methods available, the alkyne-carbonyl metathesis
(ACM) has emerged as an indispensable alternative
strategy for the synthesis of a,b-unsaturated carbonyl
compounds, which is superior to the aldol or Wittig
reaction in terms of atom- and step-efficiency. The
ACM reaction, well developed by Vieregge and
Arens,[1] Hsung,[2] Curini and Epifano,[3] Krische,[4] Ya-
mamoto[5] and so on,[6] is especially attractive because
of the simultaneous formation of C=C and C=O
bonds, two versatile functional groups in organic syn-
thesis. Promoted by Lewis or Brønsted acids, this re-
action has made significant progress over the past de-
cades. It should be noted that, the previous reports
are mainly limited to the transformation of aldehydes
[Eq. (1)]. Undoubtedly, the development of new var-
iants using other readily available carbonyl precursors
remains a long-standing challenge in the synthetic
community.
Adv. Synth. Catal. 0000, 000, 0 – 0
1
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÞÞ
These are not the final page numbers!

COMMUNICATIONS
asc.wiley-vch.de
Table 1. Screening of the reaction conditions.[a]
epoxides are common building blocks in organic syn-
thesis. They can undergo the Meinwald rearrange-
ment to form aldehydes or ketones in the presence of
Lewis acids.[9] As far as we know, epoxides were
never employed in the ACM reaction until a recent
report by Yeh et al., in which a direct synthesis of 3,4-
disubstituted pyrroles and furans was accomplished
by an intramolecular ACM featuring the use of epox-
ides as precursors to carbonyls.[6b] In contrast, the in-
termolecular version has not been realized yet, pre-
sumably due to the challenge of controlling the regio-
and stereoselectivity. Pursuing our interest in the de-
velopment of the synthetic methodology using hetero-
Entry
AgX
Solvent
Yield [%][b]
1
2
3
4
5
6
7
8
Ag2O
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
1,4-dioxane
MeCN
trace
trace
trace
80
Ag2CO3
AgOTf
AgBF4
AgSbF6
AgOAc
AgF
AgNO3
AgNO2
none
AgBF4
AgBF4
AgBF4
AgBF4
AgBF4
AgBF4
AgBF4
12
trace
trace
trace
trace
trace
62
ACHTUNGTRENNUNG
atom-substituted acetylenes,[10,11] we describe here
9
10
11[c]
12[d]
13[e]
14
15
16
17
a novel silver-catalyzed intermolecular ACM reaction
of epoxides and heteroalkynes, including ynamides,
ynol ethers, and thioacetylenes, producing a variety of
(E)-a,b-unsaturated amides, esters, and thioesters in
promising yields with excellent regio- and stereoselec-
tivity [Eq. (4)]. Mechanistically, this reaction proceeds
through a ring opening of the heteroatom-substituted
oxetene intermediate resulting from a formal [2+2]
cycloaddition.[12]
We commenced our study by investigating the reac-
tion between ynol ether 1a and epoxide 2a, with
Ag(I) as the catalyst in 1,4-dioxane under a nitrogen
atmosphere at 808C for 2 h. When the reaction was
catalyzed by Ag2O, Ag2CO3, or AgOTf, only a trace
amount of 3a was observed (Table 1, entries 1–3). To
75
trace
trace
trace
60
DMF
THF
toluene
64
[a]
Reaction conditions: 1a (0.3 mmol), 2a (0.25 mmol), AgX
(0.025 mmol), solvent (1 mL), under N2, 808C, 2 h.
Isolated yield.
1.0 equiv. of 1a was used.
5 mol% of AgBF4 was used.
[b]
[c]
[d]
[e]
Run at room temperature.
our delight, the utilization of AgBF4 resulted in the the transformation. In addition to aryl ynol ethers, the
formation of 3a in 80% yield (Table 1, entry 4). The alkyl counterpart 1l and ethoxyacetylene 1m afforded
reaction completed within 2 h, thus showing a high ef- the corresponding esters 3l and 3m in somewhat di-
ficiency. In contrast, employment of other silver salts minished yields, due to the hydrolysis of starting ma-
including AgSbF6, AgOAc, AgF, AgNO3, and AgNO2 terials 1l and 1m.
gave very low conversions (Table 1, entries 5–9). The
Additionally, we explored the possibility of assem-
reaction did not proceed in the absence of AgBF4, bling a,b-unsaturated amides via this silver-catalyzed
demonstrating its importance as the catalyst (Table 1, tandem process. To our delight, the utilization of yn-
entry 10). The catalytic loading of AgBF4 could be re-
ACHTUNGTRENaNUNG mide 1n as the alkyne component led to the produc-
duced to 5 mol%, and a comparable yield (75%) was tion of a 75% yield of (E)-a,b-unsaturated amide 3n.
observed (Table 1, entry 12). Running the reaction at Variation of the N-substituents of ynamides had no
room temperature was not successful (Table 1, significant effect on the reaction (3n–3p). Alkenyl
entry 13). Additionally, switching from 1,4-dioxane to and alkyl ynamides 1u and 1v were also amenable to
other solvents such as DMF, THF, and toluene result- this transformation, producing the desired amides 3u
ed in much lower yields (Table 1, entries 14–17).
and 3v in 83% and 81% yields, respectively. The reac-
With the optimized reaction conditions in hand, we tion of terminal ynamide 1w proceeded smoothly as
first investigated the substrate scope of ynol ethers to well to generate the disubstituted (E)-a,b-unsaturated
test the application of this Ag-catalyzed tandem epox- amide 3w in a good yield. Besides the N-sulfonyl yn-
ide rearrangement/ACM reaction, and the results are
ACHTUNGTRENaNUGN mides, 3-(2-phenylethynyl)2-oxazolidinone (1x) was
summarized in Table 2. In general, various ynol ethers also effective for the preparation of (E)-a,b-unsatu-
bearing different substituents worked well in this re- rated amide 3x. Moreover, thioalkyne 1y exhibited
action. Halogen atoms such as F, Cl, and Br were well good reactivity, giving (E)-a,b-unsaturated thioester
tolerated to give (E)-a,b-unsaturated esters 3b–3d in 3y in 75% yield. The regio- and stereoselectivity of
high yields. Pleasingly, both electron-poor and elec- resultant products was determined by NOE measure-
tron-rich ynol ethers were competent substrates for ments, and then confirmed by the single X-ray diffrac-
this reaction, forming the desired products in yields of tion analysis of amide 3t (Figure 1).[13]
72–87% (3e–3k). These results demonstrated that the
As such, we have developed a facile and efficient
electronic effect of ynol ethers has little influence on method for the construction of (E)-a,b-unsaturated
Adv. Synth. Catal. 0000, 000, 0 – 0
2
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÞÞ
These are not the final page numbers!

COMMUNICATIONS
asc.wiley-vch.de
Table 2. Scope of heteroalkynes.[a]
Figure 1. ORTEP representation of the X-ray crystal struc-
ture of 3t.
Table 3. Scope of epoxides.[a]
[a]
Reaction conditions: 1a (0.3 mmol),
2 (0.25 mmol),
AgBF4 (0.025 mmol), 1,4-dioxane (1 mL), under N2,
808C, 2 h. Yields refer to isolated products. In all cases,
the products 4 were obtained with E/Z>98:2 selectivity.
[a]
Reaction conditions:
1 (0.3 mmol), 2a (0.25 mmol),
AgBF4 (0.025 mmol), 1,4-dioxane (1 mL), under N2,
808C, 2 h. Yields refer to isolated product. In all cases,
the products 3 were obtained with E/Z>98:2 selectivity.
has little impact on this reaction. Of note, the reaction
of 2g occurred smoothly to provide (E)-a,b-unsaturat-
ed ester 4f as the sole product, demonstrating the
ꢀ
carbonyls via a Ag-catalyzed tandem epoxide rear- higher reactivity of the C C triple bond a to the OEt
rangement/ACM reaction. Subsequently, we turned group. Alkyl-substituted epoxides were also applica-
our attention to examining the reactivity of diverse ble for this transformation and gave the desired prod-
epoxides. As depicted in Table 3, epoxides 2b and 2d, ucts in promising yields with excellent regio- and ste-
possessing F and OMe substituents on the benzene reoselectivity (4g–4j). Functional groups such as Cl
ring of 2, reacted with 1a to produce (E)-a,b-unsatu- and OPh were well compatible for the current reac-
rated esters 4a and 4c in respective yields of 79% and tion (4i and 4j). Furthermore, this silver-catalyzed
77%, indicating that the electronic effect of epoxides tandem reaction could be successfully extended to
Adv. Synth. Catal. 0000, 000, 0 – 0
3
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÞÞ
These are not the final page numbers!

COMMUNICATIONS
asc.wiley-vch.de
disubstituted epoxides, as exemplified by the efficient
production of 4k and 4l. Notably, (E)-a,b-unsaturated
carbonyl compounds 3 or 4 were obtained in all cases,
and no other regio- and stereoisomers were detected
by the NMR and GC analysis.
As mentioned above, epoxides may undergo
a Lewis acid-catalyzed rearrangement to afford alde-
hydes. As such, the possibility of this reaction pro-
ceeding via an aldehyde intermediate was investigat-
ed. The subjection of 2-phenylacetaldehyde 5 to the
standard reaction conditions led to the formation of
3a in 82% yield [Eq. (5)], thus implying the formation
Scheme 1. Derivatizations of compound 3y.
ated reduction gave rise to 83% yield of branched al-
cohol 8.
In the light of the above results and previous re-
ports,[6b,15] a tentative mechanism for this transforma-
tion is proposed in Scheme 2. First, a silver-activated
of aldehyde intermediate. Furthermore, the in situ
generation of intermediate 5 was also supported by
monitoring the reaction of 1a and 2a with GC analysis
(Figure 2).
Scheme 2. Proposed mechanism.
aldehyde intermediate B is formed via a Ag(I)-cata-
lyzed ring-opening of epoxides 2, followed by a subse-
quent 1,2-H shift.[16] Then, the silver-assisted formal
[2+2] cycloaddition between B and heteroalkynes 1,
such as ynol ethers, ynamides, and thioacetylenes, pro-
duces a heteroatom-substituted oxetene intermediate
Figure 2. Kinetic profile of the Ag(I)-catalyzed tandem ep-
oxide rearrangement/ACM reaction between 1a and 2a
under the standard reaction conditions, monitored by GC
ꢀ
C. The polarization of C C triple bond of 1, caused
&
analysis with naphthalene as the internal standard. =1a,
by the electron donation from heteroatoms, may be
responsible for controlling the regioselectivity of this
cycloaddition step. Finally, an electrocyclic ring-open-
ing of C leads to the production of (E)-a,b-unsaturat-
~
*
=5, =3a.
Scheme 1 illustrates the synthetic utility of this ed carbonyls 3 or 4, together with the release of silver
silver-catalyzed tandem epoxide rearrangement/inter- catalyst for the next cycle.
molecular ACM reaction. As a result, reduction of
In summary, we have realized a novel, mild, and ef-
the C–S bond of 3y with 4 mol% of Pd/C catalyst and ficient protocol for the regio- and stereoselective
3.0 equiv of Et3SiH as the reductant produced (E)- preparation of (E)-a,b-unsaturated carbonyl com-
a,b-unsaturated aldehyde 6 in 71% yield. The Liebe- pounds via a silver-catalyzed tandem epoxide rear-
skind–Srogl coupling[14] of 3y with PhB(OH)2 pro- rangement/intermolecular
carbonyl-heteroalkyne
ceeded efficiently to provide (E)-a,b-unsaturated metathesis. It represents one of the rare examples of
ketone 7 in 77% yield. In addition, the NaBH4-medi- a regiocontrolled intermolecular ACM reaction. A va-
Adv. Synth. Catal. 0000, 000, 0 – 0
4
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÞÞ
These are not the final page numbers!

COMMUNICATIONS
asc.wiley-vch.de
[6] a) L. Karpaviciene, I. Cikotiene, Org. Lett. 2013, 15,
224; b) M.-C. P. Yeh, M.-N. Lin, C.-H. Hsu, C.-J. Liang,
J. Org. Chem. 2013, 78, 12381; c) A. Saito, J. Kasai, Y.
Odaira, H. Fukaya, Y. Hanzawa, J. Org. Chem. 2009,
74, 5644; d) L. Zhu, Z.-G. Xi, J. Lv, S. Luo, Org. Lett.
2013, 15, 4496; e) K. Bera, S. Sarkar, S. Jalal, U. Jana, J.
Org. Chem. 2012, 77, 8780; f) K. Bera, S. Sarkar, S.
Biswas, S. Maiti, U. Jana, J. Org. Chem. 2011, 76, 3539;
g) Y. Jung, I. Kim, J. Org. Chem. 2015, 80, 2001.
riety of heteroalkynes such as ynol ethers, ynamides,
and thioalkynes are well applicable for this reaction,
giving (E)-a,b-unsaturated esters, amides, and thioest-
ers in high yields with good functional group compati-
bility. The synthetic utility of this reaction is well
demonstrated by the facile synthesis of (E)-a,b-unsa-
turated aldehydes, (E)-a,b-unsaturated ketones, and
branched alcohols from the resultant products.
[7] M. Ochiai, A. Yoshimura, T. Mori, Y. Nishi, M. Hirobe,
J. Am. Chem. Soc. 2008, 130, 3742.
[8] W. Zhao, Z. Li, J. Sun, J. Am. Chem. Soc. 2013, 135,
4680.
Experimental Section
[9] a) M. W. C. Robinson, K. S. Pillinger, I. Mabbett, D. A.
Timms, A. E. Graham, Tetrahedron 2010, 66, 8377;
b) B. C. Ranu, U. Jana, J. Org. Chem. 1998, 63, 8212;
c) J. Meinwald, S. S. Labana, M. S. Chadha, J. Am.
Chem. Soc. 1963, 85, 582.
Typical Procedure for the Synthesis of (E)-a,b-
Unsaturated Carbonyl Compounds via the AgBF4-
Catalyzed Tandem Epoxide Rearrangement/ACM
Reaction
To a solution of 1a (43.8 mg, 0.3 mmol) in 1 mL of 1,4-diox-
ane was added AgBF4 (4.9 mg, 0.025 mmol), and 2a (30 mg,
0.25 mmol) under a nitrogen atmosphere. After stirring at
808C for 2 h, the reaction mixture was quenched with water,
extracted with EtOAc, washed with brine, dried over anhy-
drous Na2SO4, and concentrated. Column chromatography
on silica gel (EtOAc/petroleum ether=1:100) gave 3a as
a colorless oil; yield: 53 mg (80%). 1H NMR (600 MHz,
CDCl3): d=7.41–7.31 (m, 2H), 7.35–7.31 (m, 1H), 7.30–7.26
(m, 2H), 7.26–7.22 (m, 2H), 7.22–7.17 (m, 2H), 7.14–7.10
(m, 2H), 4.20 (q, J=7.1 Hz, 2H), 3.42 (d, J=7.8 Hz, 2H),
1.24 (t, J=7.1 Hz, 3H); 13C NMR (151 MHz, CDCl3): d=
167.0, 142.3, 138.8, 135.0, 134.5, 129.7, 128.6, 128.5, 128.1,
127.6, 126.4, 60.9, 35.6, 14.2; HR-MS (ESI): m/z=289.1205,
calcd for C18H18NaO2 (M+Na)+: 289.1204.
[10] a) L. Hu, Q. Cui, X. Chen, Z. Tan, G. Zhu, J. Org.
Chem. 2016, 81, 4861; b) C. Cheng, S. Liu, G. Zhu, Org.
Lett. 2015, 17, 1581; c) L. Hu, C. Che, Z. Tan, G. Zhu,
Chem. Commun. 2015, 51, 16641; d) Y. Yang, L. Wang,
J. Zhang, Y. Jin, G. Zhu, Chem. Commun. 2014, 50,
2347; e) G. Liu, W. Kong, J. Che, G. Zhu, Adv. Synth.
Catal. 2014, 356, 3314; f) W. Cui, J. Yin, R. Zheng, C.
Cheng, Y. Bai, G. Zhu, J. Org. Chem. 2014, 79, 3487.
[11] For selected reports on heteroatom-substituted acety-
lenes since 2015, see: a) H. Liu, Y. Yang, S. Wang, J.
Wu, X.-N. Wang, J. Chang, Org. Lett. 2015, 17, 4472;
b) S. K. Pawar, R.-L. Sahani, R. Liu, Chem. Eur. J.
2015, 21, 10843; c) L. Zhu, Y. Yu, Z. Mao, X. Huang,
Org. Lett. 2015, 17, 30; d) F. Pan, C. Shu, Y.-F. Ping, Y.-
F. Pan, P.-P. Ruan, Q.-R. Fei, L.-W. Ye, J. Org. Chem.
2015, 80, 10009; e) L. Li, B. Zhou, Y.-H. Wang, C. Shu,
Y.-F. Pan, X. Lu, L.-W. Ye, Angew. Chem. Int. Ed.
2015, 54, 8245; f) C. Shu, Y.-H. Wang, B. Zhou, X.-L.
Li, Y.-F. Ping, X. Lu, L.-W. Ye, J. Am. Chem. Soc. 2015,
137, 9567; g) R. Ding, Y. Li, C. Tao, B. Cheng, H. Zhai,
Org. Lett. 2015, 17, 3994; h) M. H. Babu, V. Dwivedi,
R. Kant, M. S. Reddy, Angew. Chem. Int. Ed. 2015, 54,
3783; i) S. Fabig, G. Haberhauer, R. Gleiter, J. Am.
Chem. Soc. 2015, 137, 1833; j) H. Huang, L. Tang, Q.
Liu, Y. Xi, G. He, H. Zhu, Chem. Commun. 2016, 52,
5605; k) H. Huang, J. Fan, G. He, Z. Yang, X. Jin, Q.
Liu, H. Zhu, Chem. Eur. J. 2016, 22, 2532; l) Y. Tokimi-
zu, M. Wieteck, M. Rudolph, S. Oishi, N. Fujii, A. S. K.
Hashmi, H. Ohno, Org. Lett. 2015, 17, 604; m) H. Jin,
L. Huang, J. Xie, M. Rudolph, F. Rominger, A. S. K.
Hashmi, Angew. Chem. Int. Ed. 2016, 55, 794; n) C. F.
Heinrich, I. Fabre, L. Miesch, Angew. Chem. Int. Ed.
2016, 55, 5170; o) I. Talbi, C. Alayrac, J.-F. Lohier, S.
Touil, B. Witulski, Org. Lett. 2016, 18, 2656. For select-
ed reviews, see: p) X.-N. Wang, H.-S. Yeom, L.-C.
Fang, S. He, Z.-X. Ma, B. L. Kedrowski, R. P. Hsung,
Acc. Chem. Res. 2014, 47, 560; q) K. A. DeKorver, H.
Li, A. G. Lohse, R. Hayashi, Z. Lu, Y. Zhang, R. P.
Hsung, Chem. Rev. 2010, 110, 5064; r) G. Evano, A.-C.
Gaumont, C. Alayrac, I. E. Wrona, J. R. Giguere, O.
Delacroix, A. Bayle, K. Jouvin, C. Theunissen, J. Gati-
gnol, A. C. Silvanus, Tetrahedron 2014, 70, 1529; s) Y.
Minami, T. Hiyama, Acc. Chem. Res. 2016, 49, 67;
t) T. G. Minehan, Acc. Chem. Res. 2016, 49, 1168.
Acknowledgements
This work is supported by the Science Technology Depart-
ment of Zhejiang Province, China (2015C31030) and the Na-
tional Natural Science Foundation of China (21172199 and
21672191).
References
[1] a) H. Vieregge, J. F. Arens, Recl. Trav. Chim. 1957, 76,
546; b) H. Vieregge, H. J. T. Bos, J. F. Arens, Recl. Trav.
Chim. 1959, 78, 664; c) H. Vieregge, J. F. Arens, Recl.
Trav. Chim. 1959, 78, 921; d) H. Vieregge, H. M.
Schmidt, J. Renema, H. J. T. Bos, J. F. Arens, Recl.
Trav. Chim. 1966, 85, 929.
[2] a) R. P. Hsung, C. A. Zificsak, L.-L. Wei, C. J. Douglas,
H. Xiong, J. A. Mulder, Org. Lett. 1999, 1, 1237;
b) K. C. M. Kurtz, R. P. Hsung, Y. Zhang, Org. Lett.
2006, 8, 231.
[3] M. Curini, F. Epifano, F. Maltese, O. Rosati, Synlett
2003, 552.
[4] J. U. Rhee, M. J. Krische, Org. Lett. 2005, 7, 2493.
[5] a) T. Jin, Y. Yamamoto, Org. Lett. 2007, 9, 5259; b) T.
Jin, F. Yang, C. Liu, Y. Yamamoto, Chem. Commun.
2009, 45, 3533.
Adv. Synth. Catal. 0000, 000, 0 – 0
5
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÞÞ
These are not the final page numbers!

COMMUNICATIONS
asc.wiley-vch.de
[12] a) M. Oblin, J.-L. Parrain, M. Rajzmann, J.-M. Pons,
Chem. Commun. 1998, 1619; b) M. Oblin, M. Rajz-
mann, J.-M. Pons, Tetrahedron 2001, 57, 3099; c) J. Sun,
V. A. Keller, S. T. Meyer, S. A. Kozmin, Adv. Synth.
Catal. 2010, 352, 839; d) K. Aikawa, Y. Hioki, N. Shimi-
zu, K. Mikmi, J. Am. Chem. Soc. 2011, 133, 20092.
free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
[14] L. S. Liebeskind, J. Srogl, J. Am. Chem. Soc. 2000, 122,
11260.
ˇ
˙
[15] C. Trujillo, G. Sꢂnchez-Sanz, L. Karpaviciene, U. Jahn,
ˇ
ˇ
˙
I. Cikotiene, L. Rulꢃsek, Chem. Eur. J. 2014, 20, 10360.
[16] P. Wipf, W. Xu, J. Org. Chem. 1993, 58, 825.
[13] CCDC 1482467 contains the supplementary crystallo-
graphic data for this paper. These data can be obtained
Adv. Synth. Catal. 0000, 000, 0 – 0
6
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÞÞ
These are not the final page numbers!

COMMUNICATIONS
Synthesis of (E)-a,b-Unsaturated Carbonyls via Silver-
Catalyzed Tandem Epoxide Rearrangement/Intermolecular
Carbonyl-Heteroalkyne Metathesis
7
Adv. Synth. Catal. 2016, 358, 1 – 7
Hui Zhu, Weiwei Jin, Jiayao He, Yan Zhang,*
Gangguo Zhu*
Adv. Synth. Catal. 0000, 000, 0 – 0
7
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÞÞ
These are not the final page numbers!