334
P. Cherkupally et al.
LETTER
149. (f) Huang, X.; He, P.; Shi, G. J. Org. Chem. 2000, 65,
627. (g) Martynov, B. I.; Semchenko, F. M. Phosphorus,
Sulfur Silicon Relat. Elem. 2002, 177, 2123.
(15) Beier, P.; Pohl, R.; Alexandrova, A. V. Synthesis 2009, 957.
(16) Chunikhin, K. S.; Kadyrov, A. A.; Pasternak, P. V.;
Chkanikov, N. D. Russ. Chem. Rev. 2010, 79, 371.
(7) Inukai, K.; Ueda, T.; Muramatsu, H. Bull. Chem. Soc. Jpn.
(17) Synthesis of (E)-1a; Typical Procedure. Trifluoroethanol
(0.16 mL, 2.25 mmol, 5 equiv) was added to a mixture of
sodium metal (29 mg, 1.26 mmol, 2.8 equiv) in anhydrous
THF (2 mL). The mixture was stirred under argon until all
sodium reacted. Solvent and excess alcohol were removed
under reduced pressure and anhydrous DMF (1.5 mL) was
added, followed by the addition of 2a (125 mg, 0.45 mmol,
1 equiv). After stirring for 2 h at r.t., saturated aqueous
NH4Cl (10 mL) was added, the product was extracted into
Et2O (3 × 15 mL) and the combined organic phase was
washed with brine (10 mL), dried over anhydrous MgSO4,
and solvent was removed under reduced pressure.
1967, 40, 1288.
(8) Boyce, C. B. C.; Webb, S. B. J. Chem. Soc., Perkin Trans. 1
1974, 1644.
(9) Zapata, A. J.; Gu, Y.; Hammond, G. B. J. Org. Chem. 2000,
65, 227.
(10) (a) Gross, R. S.; Mehdi, S.; McCarthy, J. R. Tetrahedron
Lett. 1993, 34, 7197. (b) Zhang, H.; Xu, Y.; Zhang, Z.;
Liman, E. R.; Prestwich, G. D. J. Am. Chem. Soc. 2006, 128,
5642.
(11) Zhang, X.; Burton, D. J. J. Fluorine Chem. 2001, 112, 47.
(12) (a) Blackburn, G. M.; Parratt, M. J. J. Chem. Soc., Chem.
Commun. 1983, 886. (b) Waschbüsch, R.; Carran, J.;
Savignac, P. Tetrahedron 1996, 52, 14199. (c) Keeney, A.;
Nieschalk, J.; O’Hagan, D. J. Fluorine Chem. 1996, 80, 59.
(d) Schmitt, L.; Cavusoglu, N.; Spiess, B.; Schlewer, G.
Tetrahedron Lett. 1998, 39, 4009. (e) Shen, Y.; Zhang, Y.
J. Fluorine Chem. 2001, 108, 69.
(13) (a) Iorga, B.; Eymery, F.; Savignac, P. Tetrahedron Lett.
1998, 39, 4477. (b) Martynov, B. I.; Sokolov, V. B.;
Askinenko, A. Yu.; Goreva, T. V.; Epishina, T. A.; Pushin,
A. N. Russ. Chem. Bull. 1998, 47, 1983. (c) Xu, Y.; Qian,
L.; Prestwich, G. D. Org. Lett. 2003, 5, 2267. (d) Foss, F.
W. Jr.; Snyder, A. H.; Davis, M. D.; Rouse, M.; Okusa,
M. D.; Lynch, K. R.; Macdonald, T. L. Bioorg. Med. Chem.
2007, 15, 663. (e) Cui, P.; McCalmont, F.; Tomsig, J. L.;
Lynch, K. R.; Macdonald, T. L. Bioorg. Med. Chem. 2008,
16, 2212.
Purification of the crude product by silica gel flash
chromatography (EtOAc–hexanes, 2:3), afforded pure (E)-
1a (115 mg, 98%) as a colorless oil.13a Rf = 0.47 (EtOAc–
hexanes, 2:3); IR (film): 3092, 3058, 3029, 2985, 2933,
2910, 1577, 1495, 1450, 1393, 1265, 1165, 1022, 757,
694 cm–1; 1H NMR (400 MHz, CDCl3): d = 1.39 (dt, J = 7.1,
0.4 Hz, 6 H, 2 × CH3), 4.16–4.27 (m, 4H, 2 × CH2), 6.75 (dd,
J = 42.3, 8.6 Hz, 1 H, CH), 7.33–7.43 (m, 3 H, CArH), 7.61–
7.63 (m, 2 H, CArH); 13C NMR (100 MHz, CDCl3): d = 16.3
(d, J = 6.2 Hz, CH3), 63.2 (d, J = 5.4 Hz, CH2), 123.1 (d,
J = 29.9 Hz, CH), 128.7 (CArH), 129.5 (d, J = 2.5 Hz, CArH),
130.0 (d, J = 7.7 Hz, CArH), 131.1–131.3 (m, CAr), 150.0
(dd, J = 286.1, 236.1 Hz, CF); 19F NMR (376 MHz, CDCl3):
d = –127.1 (dd, J = 97.8, 42.3 Hz); 31P NMR (162 MHz,
CDCl3): d = 5.94 (d, J = 97.8 Hz); MS (EI): m/z (%) = 258
(95) [M]+, 195 (17), 185 (70), 167 (18), 149 (89), 129 (64),
118 (61), 102 (100), 93 (30), 65 (45); HRMS (ESI+): m/z
[M + H]+ calcd for C12H17FO3P: 259.08939; found:
259.08926.
(14) (a) Beier, P.; Alexandrova, A. V.; Zibinsky, M.; Prakash, G.
K. S. Tetrahedron 2008, 64, 10977. (b) Alexandrova, A. V.;
Beier, P. J. Fluorine Chem. 2009, 130, 493.
Synlett 2011, No. 3, 331–334 © Thieme Stuttgart · New York