1784
A. Lattanzi et al. / Tetrahedron: Asymmetry 15 (2004) 1779–1785
4.4. (1S,2S,4R)-2-exo-Hydroxy-2-endo-(20-furyl)-bicyclo-
[2.2.1] heptane exo-6
Acknowledgements
ꢀ
Italian Ministero dell’Universita e Ricerca Scientifica e
Ph3P (79 mg, 0.3 mmol) was added to a solution of (þ)-
exo-5 (58 mg, 0.3 mmol) in CH2Cl2 (4 mL) under argon
atmosphere. The mixture was stirred at room tempera-
ture for 1 h. The solvent was then removed under vac-
uum while purification of the residue by flash
chromatography (petrol/Et2O, 90:10) gave (þ)-exo-6
(45 mg, 85%) as a white solid. (Found: C, 74.26; H, 7.83.
Tecnologica (MIUR) is gratefully acknowledged for
financial support.
References and notes
Calcd for C11H14O2: C, 74.13; H, 7.92%); Mp 38.2–
1. (a) Tarata, T.; Ando, W. Bull. Chem. Soc. Jpn. 1986, 59,
1275; (b) Dussault, P. H.; Lee, R. J. J. Am. Chem. Soc.
29
39.7 ꢁC (from EtOH) ½aꢁ ¼ þ47:9 (c 0.80, CHCl3); mmax
/
D
cmꢀ1 3480 (O–H), 2925, 1501, 1458, 1220; dH (400 MHz)
7.37 (1H, dd, J 1.6. 0.6), 6.30 (1H, dd, J 3.2, 1.6), 6.22
(1H, dd, J 3.2, 0.6), 2.49–2.46 (1H, m), 2.36–2.34 (1H,
m), 2.01 (1H, br s), 1.99-1.95 (1H, m), 1.92 (1H, dd, J
13.2, 2.5), 1.78 (1H, dt, J 13.2, 3.5), 1.47–1.43 (1H, m),
1.36 (1H, dt, J 12.6, 4.4), 1.31–1.22 (1H, m), 1.09–1.06
(1H, m), 0.85–0.82 (1H, m); dC (100.6 MHz) 157.9,
141.8, 109.8, 106.1, 78.2, 48.4, 44.8, 36.7, 36.2, 27.8,
23.4; m=z (EI) 178 (Mþ, 94%), 161 (100), 150 (20), 132
(82), 110 (40), 95 (23), 81 (20).
1994, 116, 4485; (c) Hamann, H.-J.; Hoft, E.; Mostowicz,
€
D.; Mishnev, A.; Urbanczyk-Lipkowska, Z.; Chmielewski,
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M. Tetrahedron 1997, 53, 185; (d) Mostowicz, D.; Jurczak,
€
M.; Hamann, H.-J.; Hoft, E.; Chmielewski, M. Eur. J.
Org. Chem. 1998, 2617.
2. (a) Adam, W.; Hoch, U.; Saha-Moller, C. R.; Schreier, P.
€
Angew. Chem., Int. Ed. 1993, 32, 1737; (b) Adam, W.;
€
Hoch, U.; Lazarus, M.; Saha-Moller, C. R.; Schreier, P.
J. Am. Chem. Soc. 1996, 117, 11898; (c) Adam, W.;
€
Lazarus, M.; Hoch, U.; Korb, M. N.; Saha-Moller, C. R.;
Schreier, P. J. Org. Chem. 1998, 63, 6123.
3. (a) Finn, M. G.; Sharpless, K. B. Asymmetric Synthesis;
Academic: New York, 1985, p 247; (b) Gao, Y.; Hanson,
R. M.; Klunder, J. M.; Ko, S. Y.; Masamune, H.;
Sharpless, K. B. J. Am. Chem. Soc. 1987, 109, 5765; (c)
4.5. General procedure for asymmetric sulfoxidation
~
Pitchen, P.; Dunach, E.; Deshmukh, M. N.; Kagan, H. B.
J. Am. Chem. Soc. 1994, 106, 8188.
A solution of (þ)-exo-5 (100 mg, 0.515 mmol) in anhy-
drous toluene (2 mL) was added to a solution of Ti(Oi-
Pr)4 (38 lL, 0.128 mmol) in anhydrous toluene (1 mL)
4. Aoki, M.; Seebach, D. Helv. Chim. Acta 2001, 84, 187.
€
5. Adam, W.; Alsters, P. L.; Neumann, R.; Saha-Moller, C.
ꢁ
R.; Seebach, D.; Zhang, R. Org. Lett. 2003, 5, 725.
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Chem. Commun. 2003, 1440; (b) Lattanzi, A.; Scettri, A.
Curr. Org. Chem. 2004, 8, 607.
7. Lattanzi, A.; Iannece, P.; Scettri, A. Tetrahedron: Asym-
metry 2004, 15, 413.
8. (a) Komatsu, N.; Hashizume, M.; Sugita, T.; Uemura, S.
J. Org. Chem. 1993, 58, 7624; (b) Nagata, T.; Imagawa,
K.; Yamada, T.; Mukaiyama, T. Bull. Chem. Soc. Jpn.
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Bonchio, M.; Licini, G.; Di Furia, F.; Mantovani, S.;
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(f) Ohta, C.; Shimizu, H.; Kondo, A.; Katsuki, T. Synlett
2002, 161.
and activated MS 4 A (100%/wt based on the sulfide),
under argon atmosphere at )20 ꢁC. The mixture was
stirred for 30 min at )20 ꢁC and then a solution of sul-
fide 7 (0.257 mmol) in anhydrous toluene (0.5 mL)
added. The reaction progress was monitored by TLC
analysis. At the end of the reaction, water (120 lL) was
added and the mixture stirred for 1 h at room temper-
ature. After filtration of the mixture over Celite with
ethyl acetate (40 mL), the solvent was evaporated under
vacuum and the crude reaction mixture purified by flash
chromatography (from petrol/diethyl ether mixtures
90:10 to pure ethyl acetate) to give (þ)-exo-6 (95% mol
recovery with respect to 5) and 8.
9. Olah, G. A.; Berrier, A. L.; Surya Prakash, G. K. J. Org.
Chem. 1982, 47, 3903.
4.6. General procedure for kinetic resolution
10. 20-Furyl 2-norbornyl cation would be stabilized by the
charge-delocalizing ability of the furyl system. It has been
reported that there is substantial p-bond character
between C-2 of the furyl moiety and the cationic carbon.
Significant shielding of 13C NMR resonance for the
cationic carbon was observed after treatment of endo-4
with FSO3H/SO2ClF at ꢀ78 ꢁC, which is indicative of
charge delocalization.9
A solution of (þ)-exo-5 (100 mg, 0.515 mmol) in anhy-
drous toluene (2 mL) was added to a solution of Ti(Oi-
Pr)4 (108 lL, 0.368 mmol) in anhydrous toluene (3 mL)
ꢁ
and activated MS 4 A (100%/wt based on the sulfoxide)
under an argon atmosphere at ꢀ20 ꢁC. The mixture was
stirred for 10 min at ꢀ20 ꢁC and then a solution of
racemic sulfoxide (0.736 mmol) in 1.5 mL of dry toluene
added. The reaction was monitored by TLC analysis. At
the end of the reaction, water (390 lL) was added and
the mixture stirred for 1 h at room temperature. After
filtration of the mixture over Celite with ethyl acetate
(50 mL), the solvent was evaporated under vacuum and
the crude reaction mixture purified by flash chroma-
tography (from petrol/diethyl ether mixtures 90:10 to
pure ethyl acetate) to give (þ)-exo-6 (95% mol recovery
with respect to 5) and unreacted 8.
11. (a) Ikegami, S.; Vander Jagt, D. L.; Brown, H. C. J. Am.
Chem. Soc. 1968, 90, 7124; (b) Goering, H. L.; Brown, H.
C.; Schewene, C. B. J. Am. Chem. Soc. 1968, 90, 6214; (c)
ꢂ
Lenoir, D.; Apeloig, Y.; Arad, D.; von Rague Schleyer, P.
J. Org. Chem. 1988, 53, 661; (d) Brown, H. C.; Ravindra-
nathan, M.; Gundu Rao, C.; Chloupek, F. J.; Rei, M.-H. J.
Org. Chem. 1978, 43, 3667; (e) Grob, C. A.; von Sprecher,
G.; Waldner, A. Helv. Chim. Acta 1983, 66, 2656.
12. Kawamura, M.; Ogasawara, K. Tetrahedron Lett. 1995,
36, 3369.