V. Nair, A. Deepthi / Tetrahedron Letters 47 (2006) 2037–2039
2039
2. (a) Winterfeldt, E.; Schumann, D.; Dillinger, H. J. Chem
Ber. 1969, 102, 1656–1664; (b) Dillinger, H. J.; Fengler,
G.; Schumann, D.; Winterfeldt, E. Tetrahedron 1974, 30,
2553–2559; (c) Dillinger, H. J.; Fengler, G.; Schumann,
D.; Winterfeldt, E. Tetrahedron 1974, 30, 2561–2564; (d)
Junjappa, H.; Saxena, M. K.; Ramaiah, D.; Lohray, B. B.;
Rath, N. P.; George, M. V. J. Org. Chem. 1998, 63, 9801–
9805.
E
E
O
O
E
HO
HO
CH2Cl2, rt
12 h, 33%
NH
N
NH
+
+
N C
O
O
N
H
O
O
N
H
O
E
2
3a
E = CO2Me
8
7
Scheme 4.
3. (a) Nair, V.; Vinod, A. U. Chem. Commun. 2000, 1019–
1020; (b) Nair, V.; Vinod, A. U.; Rajesh, C. J. Org. Chem.
2001, 66, 4427–4429; (c) Nair, V.; Vinod, A. U.; Abhilash,
N.; Menon, R. S.; Santhi, V.; Varma, L. R.; Viji, S.;
Mathew, S.; Srinivas, R. Tetrahedron 2003, 59, 10279–
10286; (d) Nair, V.; Menon, R. S.; Beneesh, P. B.;
Sreekumar, V.; Bindu, S. Org. Lett. 2004, 6, 767–769.
4. Yoshida, H.; Fukushima, H.; Ohshita, J.; Kunai, A.
Angew. Chem., Int. Ed. 2004, 43, 3935–3938.
5. (a) Wasserman, H. H.; Fukuyama, J.; Murugesan, N.;
Van Duzer, J.; Lombardo, L.; Rotello, V.; McCarthy, K.
J. Am. Chem. Soc. 1989, 111, 371–372; (b) Wasserman, H.
H.; Long, Y. O.; Zhang, R.; Parr, J. Tetrahedron Lett.
2002, 43, 3351–3353; (c) Wasserman, H. H.; Petersen, A.
K.; Xia, M. Tetrahedron 2003, 59, 6771–6784.
groups resonated at d 3.87 and d 3.66. The 13C NMR
spectrum showed resonance signals at d 185.6, d 163.8
and d 162.3 corresponding to the benzoyl and ester car-
bonyl carbons, respectively. Mass spectral data also
agreed with the proposed structure. Formation of the
iminopyrone may be rationalized as occurring via path
B. Presumably path A leading to the furan derivative
is not operative in this case due to the steric demands
imposed by the two benzoyl groups, thus allowing the
participation of another molecule of the isocyanide.
The cyclic tricarbonyl compound, alloxan hydrate 7, on
reaction with the zwitterion afforded the spiroadduct 8
albeit in low yield (Scheme 4). Unfortunately, reaction
of isocyanide–DMAD zwitterion with other cyclic tri-
ones led to intractable mixtures.
6. For reviews see: (a) Wasserman, H. H.; Parr, J. Acc.
Chem. Res. 2004, 37, 687–701; (b) Rubin, M. B.; Gleiter,
R. Chem. Rev. 2000, 100, 1121–1164; (c) Rubin, M. B.
Chem. Rev. 1975, 75, 177–202.
7. Typical experimental procedure: To a solution of the
diketoester 1a (70 mg, 0.33 mmol) and dimethyl acetyl-
enedicarboxylate (71 mg, 0.50 mmol) in anhydrous dichloro-
methane, was added after two minutes, tert-butyl iso-
cyanide (0.04 mL, 0.40 mmol) via a syringe and the
mixture was stirred at room temperature for 12 h. On
completion of the reaction, solvent was removed and the
residue was subjected to chromatography on silica gel
(100–200 mesh) using 15% ethyl acetate–hexane mixture as
eluent to afford 4a as a colourless liquid (58 mg, 56%).
Spectral data for 4a. IR (thin film) tmax: 3345, 2957, 1743,
In summary, we have uncovered a novel one-pot synthe-
sis of highly substituted furan derivatives. Substituted
furans are useful intermediates in synthetic organic
chemistry9 and there have been numerous approaches
towards their synthesis.10 The mild reaction conditions
used in the present reaction are particularly noteworthy.
Acknowledgements
1
1722, 1605, 1490, 1370, 1340, 1265, 1225, 1154, 1001. H
NMR (300 MHz, CDCl3): d 7.01 (s, 1H), 3.92 (s, 3H), 3.82
(s, 3H), 3.76 (s, 3H), 1.47 (s, 9H). 13C NMR (75 MHz,
CDCl3): d 164.2, 163.8, 162.1, 157.7, 133.3, 130.1, 128.7,
128.4, 89.0, 53.3, 52.8, 51.8, 51.4, 29.7. HRMS (EI): m/z
calcd for C14H19NO7: 313.1162, found: 313.1139.
8. Batchelor, M. J.; Gillespie, R. J.; Golec, J. M. C.;
Hedgecock, C. J. R. Tetrahedron Lett. 1993, 34, 167–
170.
The authors thank the Council of Scientific and Indus-
trial Research and the Department of Science and Tech-
nology, New Delhi, for research fellowships and other
financial assistance. The authors also thank Ms. Sau-
mini Mathew for recording NMR spectra and Ms. S.
Viji for mass analysis.
9. Lipshutz, B. H. Chem. Rev. 1986, 86, 795–819.
10. (a) Kaey, B. A.; Dibble, P. W. In Comprehensive Hetero-
cyclic Chemistry II; Katritzky, A. R., Rees, C. W., Scriven,
E. F. V., Eds.; Elsevier: Oxford, 1997; Vol. 2, pp 395–436;
(b) Donnelly, D. M. X.; Meegan, M. J. In Comprehensive
Heterocyclic Chemistry; Katritzky, A. R., Rees, C. W.,
Eds.; Pergamon: Oxford, 1984; Vol. 4, pp 657–712.
References and notes
1. (a) Do¨mling, A.; Ugi, I. Angew. Chem., Int. Ed. 2000, 39,
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2003, 8, 53–66; (c) Zhu, J. Eur. J. Org. Chem. 2003, 1133–
1144, and references cited therein.