COMMUNICATIONS
Wenbo Li et al.
Experimental Section
Typical Procedure for the Preparation of 2a
A mixture of enyne 1a (0.3 mmol, 51.0 mg), LiBr·H2O
(0.45 mmol, 1.5 equiv., 46.8 mg) and PPh3 (0.06 mmol,
20 mol%, 15.7 mg) in 1M HOAc-toluene (2 mL) was stirred
at 808C for 4 h. The reaction mixture was concentrated
under reduced pressure. The crude product was purified by
flash column chromatography on silica gel (petroleum/ethyl
acetate=10:1) to afford 2a as a colorless oil; yield: 48.4 mg
1
(68%). H NMR (400 MHz, CDCl3): d=7.74–7.69 (m, 2H),
7.47 (s, 1H), 7.41–7.36 (m, 3H), 5.94 (d, J=1.2 Hz, 1H),
5.82 (d, J=1.2 Hz, 1H), 2.48 (s, 3H); 13C NMR (100 MHz,
CDCl3): d=196.32, 139.83, 138.71, 133.39, 131.08, 130.29,
128.63, 125.22, 123.50, 27.06; MS (70 eV): m/z (%)=250
(M+, 8.95), 252 (M+ +2, 8.79), 43 (100); HR-MS: m/z=
249.9993, calcd. for C12H11O79Br: 249.9993; IR (neat): n=
3061, 1690, 1673, 1357, 1231, 1193, 902, 753, 691 cmÀ1.
Acknowledgements
We are grateful to 973 program (2011CB808600), NSFC
(21172074), Fok Ying Tung Education Foundation (121014)
and the Program of Eastern Scholar at Shanghai Institutions
of Higher Learning for financial support.
Scheme 2. Hydrohalogenation reaction of enynes and prod-
uct transformation.
References
[1] For a review, see: X. Lu, S. Ma, Chin. J. Chem. 1998,
16, 388.
[2] For hydrohalogenation reactions of electron-deficient
alkynes, see: a) S. Ma, X. Lu, J. Chem. Soc. Chem.
Commun. 1990, 1643; b) S. Ma, X. Lu, Tetrahedron
Lett. 1990, 31, 7653; c) S. Ma, X. Lu, Z. Li, J. Org.
Chem. 1992, 57, 709; d) X. Lu, G. Zhu, S. Ma, Chin. J.
Chem. 1993, 11, 267; e) S. Ma, X. Lu, Org. Synth. 1995,
72, 112; f) L. Feray, P. Perfetti, M. Bertrand, Tetrahe-
dron 2009, 65, 8733.
[3] For hydrohalogenation reaction of alkynes catalyzed by
metal, see: a) J. A. Akana, K. X. Bhattacharyya, P.
Müller, J. P. Sadighi, J. Am. Chem. Soc. 2007, 129, 7736;
b) B. C. Gorske, C. T. Mbofana, S. J. Miller, Org. Lett.
2009, 11, 4318; c) G. Bartoli, R. Cipolletti, G. D. Anto-
nio, R. Giovannini, S. Lanari, M. Marcolini, E. Marcan-
toni, Org. Biomol. Chem. 2010, 8, 3509.
[4] For hydrohalogenation of ynamides, see: a) V. Fianda-
nese, F. Babudri, G. Marchese, A. Punzi, Tetrahedron
2002, 58, 9547; b) J. A. Mulder, K. C. M. Kurtz, R. P.
Hsung, H. Coverdale, M. O. Frederick, L. Shen, C. A.
Zificsak, Org. Lett. 2003, 5, 1547.
[5] a) J. Barluenga, F. Aznar, M. A. Fernµndez, C. ValdØs,
Chem. Commun. 2002, 2362; b) A. Y. Lebedev, V. V.
Izmer, D. N. Kazyul’kin, I. Beletskaya, A. Z. Voskoboy-
nikov, Org. Lett. 2002, 4, 623; c) J. Barluenga, M. A.
Fernµndez, F. Aznar, C. ValdØs, Chem. Commun. 2004,
1400; d) J. Barluenga, M. A. Fernµndez, F. Aznar, C.
ValdØs, Chem. Eur. J. 2004, 10, 494; e) S. De, C. Day,
M. E. Welker, Tetrahedron 2007, 63, 10939.
Scheme 3. Plausible mechanism of the synthesis of dienyl
halide 2 or 3.
SN2’-type reaction to release phosphine and yield the
dienyl halide 2 or 3.[6]
In summary, we have described a phosphine-cata-
lyzed, highly regioselective and stereoselective hydro-
halogenation reaction of 2-(1-alkynyl)-2-alken-1-ones
and metal halides in the presence of acid. The multi-
ply functionalized 2-halo-1,3-diene products were ob-
tained in excellent stereoselectivities, and might be
synthetically valuable building blocks in organic syn-
thesis. The scope of this type of reactions and its syn-
thetic applications are being investigated in our labo-
ratory.
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ꢁ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2015, 357, 2651 – 2655