LETTER
Radical Addition Reaction of Perfluoroalkyl Iodides with Allenes
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(6) For some of the most recent examples, see: (a) Ogawa, A.;
Imura, M.; Kamada, N.; Hirao, T. Tetrahedron Lett. 2001,
42, 2489. (b) Tsuchii, K.; Imura, M.; Kamada, N.; Hirao, T.;
Ogawa, A. J. Org. Chem. 2004, 69, 6658. (c) Lin, H.-H.;
Chang, W.-S.; Luo, S.-Y.; Sha, C.-K. Org. Lett. 2004, 6,
3289.
(7) (a) For a review, see: Huang, W.-Y. J. Fluorine Chem. 1992,
58, 1. (b) Huang, W.-Y.; Wang, W.; Huang, B.-N. Acta
Chim. Sinica 1985, 43, 409. (c) Huang, W.-Y.; Wang, W.;
Huang, B.-N. Acta Chim. Sinica 1986, 44, 488. (d) Zur, C.;
Miethchen, R. Eur. J. Org. Chem. 1998, 531.
(10) For other kinetic resolution of E/Z isomers of alkenes, see:
(a) Foumeron, J.-D.; Chiche, M.; Piéroni, G. Tetrahedron
Lett. 1990, 31, 4875. (b) Hippeli, C.; Basso, N.; Dammast,
F.; Reißig, H.-U. Synthesis 1990, 26. (c) Morgan, B.;
Oehlschlager, A. C. Tetrahedron: Asymmetry 1993, 4, 907.
(d) Norsikian, S.; Marek, I.; Normant, J.-F. Tetrahedron
Lett. 1997, 38, 7523.
(11) Typical Procedure.
The reaction of 1a (258.8 mg, 1.99 mmol), IC4F9 (2b, 1.0482
g, 3.03 mmol), Na2S2O4 (523.6 mg, 3.01 mmol), and
NaHCO3 (253.4 mg, 3.02 mmol) in 16 mL of mixed solvent
of 1,4-dioxane and H2O (3:1) afforded 612.7 mg (65%) of
3b. 1H NMR (400 MHz, CDCl3): d = 7.37–7.28 (m, 2 H),
7.28–7.20 (m, 2 H), 7.20–7.14 (m, 1 H), 6.84 (E isomer, t,
J = 7.6 Hz, 0.36 H), 6.04 (Z isomer, t, J = 6.6 Hz, 0.64 H),
3.61–3.37 (m, 4 H). The E/Z mixture was subjected to the
next step without further characterization.
(8) (a) Huang, W.-Y.; Lü, L.; Zhang, Y.-F. Chin. J. Chem. 1990,
8, 350. (b) Cao, P.; Duan, J.-X.; Chen, Q.-Y. J. Chem. Soc.,
Chem. Commun. 1994, 737. (c) Long, Z.-Y.; Chen, Q.-Y.
Tetrahedron Lett. 1998, 39, 8487.
(9) For kinetic resolution of E/Z isomers of alkenes via the Pd-
catalyzed coupling reactions, see: (a) Ziegler, F. E.;
Chakraborty, U. R.; Weisenfeld, R. B. Tetrahedron 1981,
37, 4035. (b) Rossi, R.; Carpita, A. Tetrahedron Lett. 1986,
27, 2529. (c) Carpita, A.; Rossi, R. Tetrahedron Lett. 1986,
27, 4351. (d) Andreini, B. P.; Carpita, A.; Rossi, R.
Tetrahedron Lett. 1986, 27, 5533. (e) Andreini, B. P.;
Benetti, M.; Carpita, A.; Rossi, R. Tetrahedron 1987, 43,
4591. (f) Minato, A.; Suzuki, K.; Tamao, K. J. Am. Chem.
Soc. 1987, 109, 1257. (g) Roush, W. R.; Riva, R. J. Org.
Chem. 1988, 53, 710. (h) Minato, A. J. Org. Chem. 1991,
56, 4052. (i) Zhang, X.; Burton, D. J. J. Fluorine Chem.
2001, 112, 47. (j) Zhang, X.; Burton, D. J. J. Fluorine Chem.
2001, 112, 317. (k) Xu, J.; Burton, D. J. Org. Lett. 2002, 4,
831. (l) Xu, J.; Burton, D. J. J. Org. Chem. 2005, 70, 4346.
Then the reaction of 3b (118.7 mg, 0.25 mmol, E/Z =
1:1.78), propargyl alcohol (8.5 mg, 0.15 mmol),
Pd(PPh3)2Cl2 (6.2 mg, 8.84 × 10–3 mmol, 3.5 mol%), CuI
(1.8 mg, 9.47 × 10–3 mmol, 3.8 mol%), and Et2NH (11.0 mg,
0.15 mmol) in 0.5 mL of MeCN afforded 50.9 mg (43%) of
(Z)-3b, 4.0 mg (4%) of (Z)-4b, and 33.9 mg (34%) of (E)-4b.
(12) (a) Sonogashira, K.; Tohda, Y.; Hagihara, N. Tetrahedron
Lett. 1975, 4467. (b) Köllhofer, A.; Pullmann, T.; Plenio, H.
Angew. Chem. Int. Ed. 2003, 42, 1056. (c) Tykwinski, R. R.
Angew. Chem. Int. Ed. 2003, 42, 1566. (d) Gelman, D.;
Buchwald, S. K. Angew. Chem. Int. Ed. 2003, 42, 5993.
(e) Sakai, N.; Annaka, K.; Konakahara, T. Org. Lett. 2004,
6, 1527.
Synlett 2006, No. 8, 1263–1265 © Thieme Stuttgart · New York