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7057
consumption of the aldehyde. The reaction mixture was quenched with
saturated NH4Cl solution. The clear solution was extracted with (2 ꢁ 20 mL)
dichloromethane. The combined organic fractions were washed with brine and
dried over Na2SO4. Dichloromethane was removed on a rotary evaporator
leaving an oily residue which was purified by column chromatography (10:90
ethyl acetate/hexane) to give the alkene as an oil.
References and notes
1. Wittig, G.; Geissler, G. Liebigs Ann. Chem. 1953, 580, 44–57.
2. (a) Takeda, T. Modern Carbonyl Olefination; Wiley-VCH: Weinheim, 2004; (b)
Vedejs, E.; Peterson, M. J. Top. Stereochem. 1994, 21, 1–157; (c) Maryanoff, B. E.;
Reitz, A. B. Chem. Rev. 1989, 89, 863–927.
11. General protocol for removal of phosphine oxide: After complete consumption
of the corresponding aldehyde in the Wittig reactions employing phosphonium
salt ‘B’, the reaction mixture was quenched with saturated NH4Cl. The reaction
mixture containing the required olefin and the phosphine oxide by product
was partitioned between dichloromethane, and washed successively with
(2 ꢁ 10 mL) 10% NaOH solution to remove the phosphine oxide from the
reaction mixture.
3. (a) Robiette, R.; Richardson, J.; Aggarwal, V. K.; Harvey, J. N. J. Am. Chem. Soc.
2006, 128, 2394–2409; (b) Edmonds, M.; Abell, A. In Modern Carbonyl
Olefination; Takeda, T., Ed.; Wiley-VCH: Weinheim, 2004; pp 1–17.
4. (a) Schlosser, M.; Christmann, K. F. Angew. Chem., Int. Ed. Engl. 1966, 5, 126; (b)
Schlosser, M.; Christmann, K. F. Liebigs Ann. Chem. 1967, 708, 1–35; (c) Meyers,
A. I.; Lawson, J. P.; Carver, D. R. J. Org. Chem. 1981, 46, 3119–3123.
5. For discussion of phosphine oxide removal see: (a) Fukumoto, T.; Yamamoto, A.
US patent 5,292,973, 1994 (Niigata, JP); (b) Wang, Q.; Khoury, M. E.; Schlosser,
M. Chem. Eur. J. 2000, 6, 420–426; (c) Griffin, S.; Heath, L.; Wyatt, P. Tetrahedron
Lett. 1998, 39, 4405–4406; (d) Bootle-Wilbraham, A.; Head, S.; Longstaff, J.;
Wyatt, P. Tetrahedron Lett. 1999, 40, 5267–5270.
6. (a) McEwen, W. E.; Cooney, J. V. J. Org. Chem. 1983, 48, 983–987; (b) Zhang, X.;
Schlosser, M. Tetrahedron Lett. 1993, 34, 1925–1928; (c) Dunne, E. C.; Coyne, E.
J.; Crowley, P. B.; Gilheany, D. G. Tetrahedron Lett. 2002, 43, 2449–2453.
7. Oh, J. S.; Kim, B. H.; Kim, Y. G. Tetrahedron Lett. 2004, 45, 3925–3928.
8. Maryanoff, B. E.; Reitz, A. B.; Duhl-Emswiler, B. A. J. Am. Chem. Soc. 1985, 107,
217–226.
12. NMR data for olefins (derived from (1a–e): 1H NMR (200 MHz, CDCl3); d (ppm):
as a mixture of (Z)- and (E)-isomers,
1-(40-Chlorophenyl)prop-1-ene (from 1a):13 d 7.29 (2H, d, J = 8.74 Hz, ArH), 7.21
(2H, d, J = 8.52 Hz, ArH), 6.30–6.43 (1Ha, m, J = 16.37 Hz, CHa@CHbMe), 6.19
(1Hb, dq, J = 6.12 Hz, J = 15.76 Hz, E-isomer), 5.80 (1Hb, dq, J = 7.18 Hz,
J = 11.53 Hz, Z-isomer), 1.87 (3H, d, J = 7.2 Hz, Z-isomer and J = 6.12 Hz, E-
isomer).
1-(40-Methoxyphenyl)prop-1-ene (from 1b):14–18 d 7.26 (2H, d, J = 8.7 Hz, ArH),
6.83 (2H, d, J = 8.7 Hz, ArH), 6.34 (1Ha, m, J = 15.86 Hz, CHa@CHbMe), 6.08 (1Hb,
dq, J = 6.44 Hz, J = 15.66 Hz, E-isomer), 5.70 (1Hb, dq, J = 7.04 Hz, J = 11.37 Hz,
Z-isomer), 3.81 (3H, s, OMe, Z-isomer), 3.79 (3H, s, OMe, E-isomer), 1.89 (3H, d,
J = 7.04 Hz, Z-isomer), 1.85 (3H, d, J = 6.46 Hz, E-isomer).
9. Robiette, R.; Richardson, J.; Aggarwal, V. K.; Harvey, J. N. J. Am. Chem. Soc. 2005,
127, 13468–13469.
1-(30-Methoxyphenyl)prop-1-ene (from 1c):14–17 d 7.16–7.29 (1H, m, ArH), 6.83–
6.96 (2H, m, ArH), 6.71–6.80 (1H, m, ArH), 6.33–6.45 (1Ha, m, J = 16.73 Hz,
CHa@CHbMe), 6.22 (1Hb, dq, J = 6.1 Hz, J = 15.82 Hz, E-isomer), 5.79 (1Ha, dq,
J = 7.21 Hz, J = 11.60 Hz, Z-isomer), 3.81 (3H, s, OMe, Z-isomer), 3.80 (3H, s,
OMe, E-isomer), 1.90 (3H, d, J = 7.21 Hz, Z-isomer), 1.87 (3H, d, J = 6.1 Hz, E-
isomer).
10. (a) Typical procedure for the Wittig reaction with phosphonium salts A and D:
Phosphonium salt A or D (0.50 mmol), in a 25 mL flame-dried flask equipped
with magnetic stir bar, rubber septum and an argon inlet, was suspended in
anhydrous THF (2.0 mL), and the suspension was cooled to ꢀ78 °C. sec-BuLi
(0.55 mmol, 1.4 M in pentane) was added to the reaction mixture to yield a red
solution. After 15 min, HMPA (0.55 mmol) was added to the reaction mixture
at ꢀ78 °C. After 2 h, the corresponding aldehyde (0.50 mmol) was slowly
added to the flask at ꢀ78 °C. The reaction mixture was stirred for 2 h at ꢀ78 °C,
and then gradually warmed to room temperature and stirred for an additional
3 h. TLC analysis of the reaction mixture showed complete consumption of the
aldehyde. The reaction mixture was quenched with saturated NH4Cl solution.
The clear solution was extracted with (2 ꢁ 20 mL) dichloromethane. The
combined organic fractions were washed with brine and dried over Na2SO4.
Dichloromethane was removed on a rotary evaporator leaving an oily residue
which was purified by column chromatography (10:90 ethyl acetate/hexane)
to give the alkene as an oil.
1-(30,40-Dioxymethylenephenyl)prop-1-ene (from 1d):15,17,19 d 6.69–6.90 (3H, m,
ArH), 6.31 (1Ha, m, J = 15.75 Hz, CHa@CHbMe), 6.05 (1Hb, dq, J = 6.47 Hz,
J = 15.65 Hz, E-isomer), 5.69 (1Hb, dq, J = 7.12 Hz, J = 11.54 Hz, Z-isomer), 5.94
(2H, s, –OCH2O–, Z-isomer), 5.92 (2H, s, –OCH2O–, E-isomer), 1.87 (3H, d,
J = 7.12 Hz, Z-isomer), 1.84 (3H, d, J = 6.47 Hz, E-isomer).
Tridec-2-ene (from 1e):20 1H NMR (600 MHz, CDCl3); d 5.37–5.45 (2H, m), 1.94–
1.97 (2H, m, E-isomer), 2.00–2.05 (2H, m, Z-isomer), 1.63–1.64 (3H, d,
J = 4.2 Hz, E-isomer), 1.59–1.60 (3H, d, J = 6.6 Hz, Z-isomer), 1.24–1.33 (16H,
m), 0.86 (3H, t, J = 7.2 Hz).
13. Ikeda, Y.; Nakamura, T.; Yorimitsu, H.; Oshima, K. J. Am. Chem. Soc. 2002, 124,
6514–6515.
(b) Typical procedure for the Wittig reaction with phosphonium salts B and C:
14. Yu, J.; Gaunt, M. J.; Spencer, J. B. J. Org. Chem. 2002, 67, 4627–4629.
15. Joshi, B. P.; Sharma, A.; Sinha, A. K. Tetrahedron 2005, 61, 3075–3080.
16. Roberts, J. C.; Pincock, J. A. J. Org. Chem. 2006, 71, 1480–1492.
17. Buss, A. D.; Warren, S. J. Chem. Soc., Perkin. Trans. 1 1985, 2307–2325.
18. Goez, M.; Eckert, G. Helv. Chim. Acta 2006, 89, 2183–2199.
19. Mohottalage, S.; Tabacchi, R.; Guerin, P. Flavour Fragr. J. 2007, 22, 130–138.
20. Hodgson, D. M.; Fleming, M. J.; Stanway, S. J. J. Org. Chem. 2007, 72, 4763–
4773.
Phosphonium salt
B or C (0.50 mmol) was suspended in anhydrous THF
(2.00 mL) in a 25 mL flame-dried flask equipped with magnetic stir bar, rubber
septum, and an argon inlet, and the suspension was cooled to ꢀ78 °C. sec-BuLi
(1.05 mmol, 1.4 M in pentane) was added to the reaction mixture to yield a red
solution. After 15 min, HMPA (1.05 mmol) was added to the reaction mixture
at ꢀ78 °C. After 2 h, the corresponding aldehyde (0.50 mmol) was slowly
added to the flask at ꢀ78 °C and the reaction mixture was stirred for 2 h at
ꢀ78 °C, and then gradually warmed to room temperature and stirred for an
additional 3 h. TLC analysis of the reaction mixture showed complete