Z. Tan et al. / Tetrahedron 56 (2000) 7457–7461
7461
5H); 13C NMR (50 MHz, CDCl3) d 24.3, 30.9, 31.7, 35.5,
References
37.4, 73.3, 125.6, 128.2, 128.2, 142.0, 207.0. This
compound was unstable and was used in the diazo decom-
position immediately after column chromatography.
1. For recent comprehensive reviews on the reaction of a-diazo
carbonyl compounds, see: (a) Doyle, M. P.; McKervey, M. A.; Ye,
T. Modern Catalytic Methods for Organic Synthesis with Diazo
Compounds; Wiley-Interscience: New York, 1998. (b) McKervey,
M. A.; Ye, T. Chem. Rev. 1994, 94, 1091.
Pentyl 5-diazo-4-oxo-pentanoate 17. Oil; IR (Neat): n
2958, 2105, 1734, 1645, 1382, 1174 cmϪ1 1H NMR
;
(200 MHz, CDCl3) d 0.90 (t, J6.6 Hz, 3H), 1.28–1.35
(m, 4H), 1.55–1.66 (m, 2H), 2.65 (s, 4H), 4.08 (t,
J6.8 Hz, CH2), 5.32 (s, br, 1H); 13C NMR (50 MHz,
CDCl3) d 192.6, 172.3, 64.6, 54.3, 34.7, 28.4, 28.0, 27.7,
22.0, 13.7; MS m/z (relative intensity) 184 [(MϪN2)ϩ, 7%],
156 (4), 125 (3), 114 (4), 101 (21); HRMS calcd for
(MϪN2)ϩ, C10H16O3 184.1099, found 184.1102.
2. (a) Lesbre, M.; Buisson, R. Bull. Soc. Chim. Fr. 1957, 1204.
(b) Padwa, A.; Eastman, D. J. Org. Chem. 1969, 34, 2728.
(c) Doyle, M. P.; Taunton, J.; Oon, S.-M.; Liu, M. T. H.;
Soundararajan, N.; Platz, M. S.; Jacson, J. E. Tetrahedron Lett.
1988, 29, 5863. (d) Jackson, J. E.; Soundararajan, N.; Platz,
M. S.; Doyle, M. P.; Liu, M. T. H. Tetrahedron Lett. 1989, 30,
1335. (e) Andrey, O.; Landais, Y.; Planchenault, D.; Weber, V.
Tetrahedron 1995, 44, 12083.
Diazo a-ketoester 11 was prepared by standard diazo trans-
3. (a) Wang, J.; Chen, B.; Bao, J. J. Org. Chem. 1998, 63, 1853.
(b) Wang, J.; Liang, F.; Chen, B. J. Org. Chem. 1998, 63, 8589.
(c) Chen, B.; Liang, F.; Chen H.; Wang, J. J. Chem. Res., Synop.
1998, 410. (d) Wang, J.; Liang, F. Chin. Chem. Lett. 1998, 9, 701.
(e) Wang, J.; Hou, Y. J. Chem. Soc. Perkin Trans. 1 1998, 1919.
(f) Wang, J.; Hou, Y. J. Chem. Soc. Perkin Trans. 1 1999, 2277.
(g) Wang, J.; Hou, Y.; Wu, P.; Qu, Z.; Chen, A. S. C. Tetrahedron:
Asymmetry 1999, 10, 4553.
4. Bu3SnH is known to react with isonitriles and nitro groups, see:
Barton, D. H. R.; Mortherwell, W. B. Pure Appl. Chem. 1981, 53,
15. (b) Ono, N.; Kaji, A. Synthesis 1986, 693. The addition of
Bu3SnH to CvN group is also known, see: Palmisano, G.;
Lesma, G.; Nali, M.; Rindone, B.; Tollari, S. Synthesis 1985, 1072.
5. Wanger, R. W.; Tome, J. M. J. Am. Chem. Soc. 1950, 72, 3477.
6. (a) Horner, L.; Schwarz, H. Tetrahedron Lett. 1966, 3579.
(b) Horner, L.; Schwarz, H. Liebigs Ann. Chem. 1971, 747, 1.
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Soc. Perkin Trans. 1 1985, 493.
fer reaction (TsN3/Et3N/MeCN, room temperature).3a
Methyl 2-diazo-3-oxo-7-phenylheptanoate 11. Oil; IR
(Neat) n 2930, 2129, 1727, 1656, 1435, 1308, 1220 cmϪ1
;
1H NMR (200 MHz, CDCl3) d 1.65–1.70 (m, 4H), 2.63 (t,
J6.4 Hz, 2H), 2.87 (t, J6.2 Hz, 2H), 3.82 (s, 3H), 7.15–
7.31 (m, 5H); 13C NMR (50 MHz, CDCl3) d 23.95, 30.88,
35.63, 39.91, 52.10, 125.66, 128.23, 128.34, 142.19, 161.74,
192.64; MS m/z (relative intensity) 232 [(MϪN2)ϩ, 6 %],
200 [(MϪN2ϪMeOH)ϩ, 29], 172 (15), 144 (20), 117 (41),
91 (100); HRMS calcd for (MϪN2)ϩ, C14H16O3 232.1099,
found 232.1099.
General procedure for the Cu(acac)2 catalyzed diazo
decomposition in the presence of Bu3SnH
Method A. The diazo compound (1.0 mmol), Cu(acac)2
(0.01 mmol) and Bu3SnH (2.5 mmol) was dissolved in dry
benzene (20 mL). The solution was refluxed until the
completion of the diazo decomposition, as indicated by
TLC. The reaction mixture was cooled down and the solvent
was removed under reduced pressure to give a crude
mixture, which was subjected to column chromatography.
8. Cox, G. G.; Miller, D. J.; Moody, C. J.; Sie, E. H. B.;
Kulagowski, J. J. Tetrahedron 1994, 50, 3195.
9. The a-stannyl ketone can be easily identified by a singlet at d
3.24, with characteristic tin statellites corresponding to
J119Sn69.6 Hz and J117Sn67.2 Hz, due to the a-CH2SnPh3
group. The acetophenone was identified by the singlet of the
methyl group at d 2.06. Ph3SnH was used in the NMR study
instead of Bu3SnH because of the simplicity of the spectra in the
high field.
General procedure for the diazo decomposition in the
presence of Bu3SnH under photochemical conditions
10. Pirrung, M. C.; Morehead Jr., A. T. J. Am. Chem. Soc. 1996,
118, 8162.
11. Watanabe, Y.; Yoneda, T.; Ueno, Y.; Toru, T. Tetrahedron
Lett. 1990, 31, 6669.
12. March, J. Advanced Organic Chemistry; 4th ed.; Wiley-
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13. Arndt, F. Organic Synthesis Collective Volume 3, 1943; pp 165
and 461.
14. Wilds, A. L.; Meader Jr., A. L. J. Org. Chem. 1948, 13, 763.
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16. Pellicciari, R.; Natalini, B.; Cecchetti, S.; Santucci, S.
Tetrahedron Lett. 1984, 25, 3103.
Method B. The diazo compound (1.0 mmol) and Bu3SnH
(2.5 mmol) was dissolved in benzene (20 mL) in a Pyrex
tube. The solution was irradiated with a 300 W high
pressure Hg lamp at room temperature. Upon completion
of the reaction, the solvent was removed and the crude
residue was purified by column chromatography.
Compounds 10, 18, 20, 21, 23 and 24 are known3f,17,18,19,20
and their data were consistent with that reported in the
literature.
17. Ho, T.-L.; Wong, C. M. Synth. Commun. 1975, 5, 91.
18. Kise, N.; Suzumoto, T.; Shono, T. J. Org. Chem. 1994, 59,
1407.
Acknowledgements
19. Kasturi, T. R.; Mathew, L.; Sattigeri, J. A. Indian J. Chem.,
Sect. B 1990, 29, 1004.
20. Molander, G. A.; Stengel, P. J. J. Org. Chem. 1995, 60, 6660.
The project was generously supported by Natural Science
Foundation of China (Grant No. 29972002).