3426
Y. Imura et al. / Tetrahedron 66 (2010) 3421–3426
N-methyl-N-[4-(diphenylphosphino)benzyl]pyrrolidinium
mide B was obtained in 93% yield.
bro-
under an argon atmosphere. The products were extracted by ether
mentioned as above.
4.6. Typical procedure for the Sonogashira reaction with ion-
supported Ph3P A or B in ionic liquid
4.4. Typical procedure for the Mitsunobu reaction with ion-
supported Ph3P
A mixture of [bmim]PF6 (2 mL) and 4-(diphenylphosphino)-
benzyltrimethylammoniumbromideA(66 mg,16 mol %)wasdriedby
a vacuum pump for 2 h at 60 ꢀC. Then, PdCl2 (14 mg, 8 mol %), CuI
(19 mg,10 mol %), p-iodotoluene (218 mg,1.0 mmol), phenylacetylene
(157 mg, 1.5 mmol), and Et3N (202 mg, 2.0 mmol) were added to the
mixture, andtheobtainedmixturewasstirredfor3 hat70 ꢀCunderan
argon atmosphere. After the reaction, the products were extracted by
ether (5 mLꢂ6). Removal of the solvent from the extracts gave phe-
nyl(p-tolyl)acetylene in 100% yield with >95% purity.
Recyclic use of ionic liquid containing A was carried out as fol-
lows. The ionic liquid reaction media containing PdCl2, CuI, and A
was dried by vacuum pump for 2 h at 60 ꢀC. Then, p-iodotoluene
(218 mg, 1.0 mmol), phenylacetylene (157 mg, 1.5 mmol), and Et3N
(202 mg, 2.0 mmol) were added to the mixture, and the obtained
mixture was again stirred for 2 h at 70 ꢀC under an argon atmo-
sphere. The products were extracted by ether mentioned as above.
1-Methyl-3-[40-(diphenylphosphino)benzyl]pyrrolidinium bro-
mide B (660 mg, 1.5 mmol) was dried by a vacuum pump for 2 h at
70 ꢀC. To the flask containing 1-methyl-3-[40- (diphenylphosphino)-
benzyl]pyrrolidinium bromide B was added a solution of 3-(40-
methoxyphenyl)propanoic acid (180 mg, 1.0 mmol) and 2-phenyl-
ethanol (1.1 mmol) in dichloromethane (6 mL). Then, 40% diisopropyl
azodicarboxylate in a toluene solution (0.758 mL, 1.5 mmol) was
added dropwise to the mixture, and the obtained mixture was stirred
for 2 h at 40 ꢀC under an argon atmosphere. After the reaction, ether
(10 mL) was added and the mixture was stirred for 10 min at 0 ꢀC.
Then, the mixture was filtered and washed with ether. Removal of the
solvent from the filtrates gave 2-phenylethyl 3-(40-methoxyphenyl)
propanoate in >90% purity. It was purified by short column chro-
matography on silica gel (eluent: AcOEt and hexane¼5:1) to give
2-phenylethyl 3-(40-methoxyphenyl)propanoatein87% yield. Theco-
product, 1-methyl-3-[40-(diphenylphosphono)benzyl]pyrrolidinium
bromide was recovered by the above filtration in 99% yield.
4.6.1. Phenyl(p-tolyl)acetylene. Mp 69–70 ꢀC (lit.9 mp 69–71 ꢀC); IR
(KBr) 2218 cmꢁ1
;
1H NMR:
d
¼2.37 (s, 3H), 7.16 (d, J¼7.8 Hz, 2H),
4.4.1. 2-Phenylethyl 3-(40-methoxyphenyl)propanoate. Oil; IR(neat):
7.32–7.36 (m, 3H), 7.43 (d, J¼7.8 Hz, 2H), 7.51–7.53 (m, 2H); 13C NMR:
1734, 1514,1248,1177,1036, 701 cmꢁ1; 1H NMR (CDCl3,TMS)
d¼2.58
d¼21.5, 88.7, 89.6, 120.2, 123.5, 128.0, 128.3, 129.1, 131.5, 131.6, 138.3.
(t, J¼7.9 Hz, 2H), 2.86 (t, J¼7.7 Hz, 2H), 2.91 (t, J¼7.0 Hz, 2H), 3.78 (s,
3H), 4.28 (t, J¼7.1 Hz, 2H), 6.82 (d, J¼8.7 Hz, 2H), 7.07 (d, J¼8.7 Hz,
Acknowledgements
2H), 7.17–7.32 (m, 5H); 13C NMR (CDCl3, TMS):
36.28 (s), 55.34 (p), 64.98 (s), 113.96 (t), 126.63 (t), 128.57 (t), 128.99
(t),129.32 (t),132.64 (q),137.91 (q),158.13 (q),172.98 (q); HRMS (EI)
Calcd for C18H20O3 Mþ: 284.1412. Found M: 284.1412.
d
¼30.15 (s), 35.18 (s),
Financial support of a Grant-in-Aid for Scientific Research
(No.20550033) from the Ministry of Education, Science, Sports and
Culture of Japan and Futaba Electronics Memorial Foundation in
Japan is gratefully acknowledged.
4.5. Typical procedure for the Mizoroki–Heck reaction with
ion-supported Ph3P A or B in ionic liquid
References and notes
1. Fieser, L. F.; Fieser, M. Reagents for Organic Synthesis; John Wiley & Sons: New York,
NY, 1967; Vol. 1; p 1247; 1969, Vol 2, p 445; 1972, Vol 3, p 320; 1974, Vol 4, p 549;
1975, Vol 5, p 725; 1977, Vol 6, p 643; 1979, Vol 7, p 404; 1980, Vol 8, p 516; 1981, Vol
9, p 503; 1982, Vol 10, p 448; 1984, Vol 11, p 588; 1986, Vol 12, p 550; 1988, Vol 13, p
331; 1989, Vol 14, p 336; 1990, Vol 15, p 352; 1992, Vol 16, p 366.
2. Comprehensive Organic Transformations; Larock, R. C., Ed.; VCH: New York, NY,
1989; p 353 and 849.
3. (a) Mizoroki, T.; Mori, K.; Ozaki, A. Bull. Chem. Soc. Jpn. 1971, 44, 581; (b) Heck, R.
F.; Nolley, J. P. J. Org. Chem. 1972, 37, 2320; (c) Sonogashira, K.; Tohda, Y.; Hagi-
hara, N. Tetrahedron Lett. 1975, 16, 4467; (d) Scott, W. J.; Crisp, G. T.; Stille, J. K.
J. Am. Chem. Soc. 1984, 106, 4630; (e) Stille, J. K. Pure Appl. Chem. 1985, 57, 1771; (f)
Miyaura, N.; Yanagi, T.; Suzuki, A. Tetrahedron Lett. 1979, 3437; (g) Suzuki, A. Acc.
Chem. Res. 1982, 15, 178.
A mixture of [bmim]PF6 (2 mL) and N-methyl-N-[4-(diphenyl-
phosphino)benzyl]pyrrolidinium bromide B (66 mg, 15 mol %) was
dried by a vacuum pump for 2 h at 60 ꢀC. Then, Pd(OAc)2 (18 mg,
8 mol %), p-iodotoluene (218 mg,1.0 mmol), methyl acrylate (95 mg,
1.1 mmol), and Et3N (202 mg, 2 mmol) were added to the mixture,
and the obtained mixture was stirred for 2 h at 60 ꢀC under an argon
atmosphere. After the reaction, the products wereextractedbyether
(5 mLꢂ6). Removal of the solvent from the extracts gave methyl
p-methylcinnamate in 95% (167 mg) with >95% purity.
4. Ion-supported PhI: (a) Akiike, J.; Yamamoto, Y.; Togo, H. Synlett 2007, 2168; (b)
Kawano, Y.; Togo, H. Synlett 2008, 217; (c) Moroda, A.; Togo, H. Synthesis 2008,
1257; (d) Kawano, Y.; Togo, H. Tetrahedron 2009, 65, 6251; (e) Ishiwata, Y.; Togo,
H. Tetrahedron Lett. 2009, 50, 5354.
5. Imamoto, T.; Kikuchi, S.; Miura, T.; Wada, Y. Org. Lett. 2001, 3, 87.
6. Carmichael, A. J.; Earle, M. J.; Holbrey, J. D.; McCormac, P. B.; Seddon, K. R. Org.
Lett. 1999, 1, 997.
7. Braun, V. Ber. 1911, 43, 2837.
8. Myrboh, B. J. Org. Chem. 1983, 48, 5327.
9. Kakusawa, N.; Yamaguchi, K.; Kurita, J. J. Organomet. Chem. 2005, 690, 2956.
4.5.1. Methyl p-methylcinnamate. Mp 58–58 ꢀC (lit.8 mp 57–58 ꢀC).
Recyclic use of ionic liquid containing B was carried out as follows.
After extraction with ether as above, the recovered ionic liquid
containing Pd(OAc)2 and B was dried by a vacuum pump for 2 h at
60 ꢀC. Then, p-iodotoluene (218 mmol, 1.0 mmol), methyl acrylate
(95 mg, 1.1 mmol), and Et3N (202 mg, 2 mmol) were added to the
mixture, and the obtained mixture was again stirred for 2 h at 60 ꢀC