5450
W. Li et al. / Tetrahedron Letters 51 (2010) 5448–5450
Cl
O
O
H
O
Ph
Me
O
OH
OH
O
Me
OR3
OR3
Me
Cl
Cl
O
Cl
Cl
Cl
Cl
O
HO R3
taut.
Cl
Cl
OEt
Ph
O
+
EtOH
ð3Þ
H
90 oC, 5 h
79%
OH
Cl
O
O
5b
OH
1a
OH
Cl
F
Cl
1
Cl
7
E
Cl
OR3
OR3
Cl
H
Cl
O
O
O
HO
O
Cl
Cl
Me
Table 2
Me
π
6
-electrocyclic
The reactions of tropones 1b with alcohols 5a
O
Cl
OH
Cl
OH
HCl
OR3
Cl
Me
O
O
Me
6
OH
Cl
Cl
Cl
Cl
Cl
H
G
O
OH
+
R3OH
O
100 oC, 5 h
Scheme 2. A tentative mechanism for the formation of 6
OR3
Me
6
OH
Cl
1b
5
Entry
6
7
Isolated yield (%)
for the synthesis of the functionalized phthalazin-1(2H)-ones and
3-hydroxyisobenzofuran-1(3H)-ones. Further investigation of the
reactivity of the multiple functional tropones 1 and the applica-
tions of phthalazinones 3 and isobenzofuranones 6 are in progress.
Cl
O
Cl
Cl
Cl
1b
MeOH 5a
EtOH 5b
6a 95
O
OMe
Me
Me
Me
OH
Cl
Acknowledgment
O
We thank the NSFC (20832002) for the financial support.
2c
6b 85
O
OEt
OH
Cl
Supplementary data
O
OH
5c
Supplementary data associated with this article can be found, in
O
3
4
5
6c 70
O
OH
Cl
References and notes
d
OH
5d
—
1. Dewar, M. J. S. Nature 1945, 155, 50.
2. (a) Morita, N.; Toyota, K.; Ito, S. Heterocycles 2009, 78, 1917; (b) Pietra, F. Chem.
Rev. 1973, 73, 293; (c) Pietra, F. Acc. Chem. Res. 1979, 12, 132; (d) Pauson, P. L.
Chem. Rev. 1955, 55, 9.
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McDougall, P. T. Org. Lett. 2009, 11, 3782; (c) Nair, V.; Poonoth, M.; Vellalath, S.;
Suresh, E.; Thirumalai, R. J. Org. Chem. 2006, 71, 8964; (d) Du, Y.; Feng, J.; Lu, X.
Org. Lett. 2005, 7, 1987.
4. (a) Gao, W.; Sun, M.; Li, Y.; Li, W.; Imafuku, K. J. Heterocycl. Chem. 2009, 46, 1302;
(b) Ishizu, T.; Mori, M.; Kanematsu, K. J. Org. Chem. 1981, 46, 526.
5. (a) Kogler, H.; Fehlhaber, H.-W.; Leube, K.; Durckheimer, W. Chem. Ber. 1989,
122, 2205; (b) Schenck, G. O.; Brahler, B.; Cziesla, M. Angew. Chem. 1956, 68, 247.
6. Li, H.; Li, W.; Li, Z. Chem. Commun. 2009, 3264.
7. (a) Jain, R. P.; Vederas, J. C. Bioorg. Med. Chem. Lett. 2004, 14, 3655; (b) Al-Assar,
F.; Zelenin, K. N.; Lesiovskaya, E. E.; Bezant, I. P.; Chakchir, B. A. Pharm. Chem. J.
2002, 36, 598.
8. (a) Pakulska1, W.; Malinowski, Z.; Szczesniak, A. K.; Czarnecka1, E.; Epsztajn, J.
Arch. Pharm. Chem. Life Sci. 2009, 342, 41; (b) Li, Y.-X.; Luo, Y.-P.; Xi, Z.; Niu, C.;
He, Y.-Z.; Yang, G.-F. J. Agric. Food Chem. 2006, 54, 9135.
9. (a) Vina, D.; del Olmo, E.; Lopez-Perez, J. L.; Feliciano, A. S. Tetrahedron 2009, 65,
1574; (b) Grasso, S.; De Sarro, G.; De Sarro, A.; Micale, N.; Zappala, M.; Puia, G.;
Baraldi, M.; De Micheli, C. J. Med. Chem. 2000, 43, 2851; (c) Attanasi, O. A.;
Filippone, P.; Fiorucci, C.; Mantellini, F. Tetrahedron Lett. 1999, 40, 3891; (d)
Lefkaditis, D. A.; Nicolaides, D. N.; Papageorgiou, G. K.; Stephanidou-Stephana, J.
J. Heterocycl. Chem. 1990, 27, 227.
HO
O
OH
5e
Cl
O
O
6e 68
6f 54
Me
Me
OH
OH
Cl
O
Cl
O
OH
5f
O
6
O
OH
O
a
b
c
Conditions: 1 (0.1 mmol), 5 (1.0 mL); under nitrogen atmosphere.
80 °C.
90 °C.
No reaction.
d
In summary, we have reported a novel hydrazine-/alcohol-in-
duced ring contraction of tropones, which provides a new protocol