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B. Panunzi et al. / Tetrahedron Letters 44 (2003) 8753–8756
ethanone 5b in good yields. No other intermediates
have been observed during this last transformation.
These results are still in agreement with those observed
with the PhSeSePh/(NH4)2S2O8 system,11 and suggest
that probably a similar reaction pathway could be
invoked. In conclusion, the chemistry of electrophilic
iodine and selenium species continues to give very good
results that, especially concerning the selenium
behaviour, are still almost completely unpredictable.
Much more could be done to understand the role of the
I(III) species together with solvents to address the
reactions observed.
were employed working at 45°C. The BTI being added in
the CH3CN experiments, was 1.2 molar equiv., while 1.8
molar equiv. of BTI were necessary to obtain the a,a-
dimethoxy carbonyl derivatives. All the reactions were
complete in less than 4 h. Almost complete recovery of
diphenyl diselenide was achieved from the preparation of
a,a-dimethoxy carbonyl derivatives. For the preparation
of monoprotected vicinal dicarbonyl compounds we tried
to use a catalytic amount of diphenyldiselenide but the
reactions were too slow and some of the starting ketones
were consumed by the oxidant, to give unknown com-
pounds. The products obtained were fully characterised
by 1H and 13C NMR spectroscopy and MS. Selected
experimental data: 2e: solid, mp 83–86°C (uncorrected);
lH (CDCl3, 200 MHz): 7.85 (d, J=7.5 Hz, 1H), 6.65 (d,
J=7.5 Hz, 1H), 3.80 (s, 3H), 2.9 (t, J=6.4 Hz, 2H), 2.65
(t, J=6.4 Hz, 2 H), 2.0 (quintet, J=6.4 Hz, 2H); lC
(CDCl3, 50 MHz): 197.3, 157.2, 140.8, 136.1, 115.1, 55.8,
39.3, 23.7, 21.9; GC–EIMS: m/z 302 (M+) (87), 274 (30),
246 (23), 216 (13), 127 (39), 119 (51), 50 (100). 3b: solid,
mp 156–159°C (uncorrected); lH (CDCl3, 300 MHz): 7.84
(dd, J=8.5, 2.1 Hz, 1H), 7.6 (m, 2H), 7.56 (d, J=2.1 Hz,
1H), 7.4 (m, 3H), 6.85 (d, J=8.5 Hz, 1H) 3.98 (s, 3H),
2.37 (s, 3H); lC (CDCl3, 50 MHz): 196.4, 160.4, 135.6,
131.2, 129.6, 128.9, 122.8, 56.3, 26.2; GC–EIMS: m/z 306
(M+) (4), 304 (2), 291 (2), 91 (6), 77 (22), 43 (100). 5e: lH
(CDCl3, 200 MHz): 7.45 (d, J=7.9 Hz, 1H), 7.15 (t,
J=7.9 Hz, 1H), 6.85 (d, J=7.9 Hz, 1H), 3.95 (s, 3H), 3.3
(s, 6H), 3.0 (t, J=6.2 Hz, 2H), 2.3 (t, J=6.2 Hz, 2H); lC
(CDCl3, 50 MHz): 191.7, 156.2, 132.0, 126.8, 119.3,
114.0, 96.6, 55.2, 49.3, 29.7, 20.0; GC–EIMS: m/z 236
(M+) (12), 205 (11), 177 (100), 91 (32), 77 (27). 5g:12 solid,
mp 50–53°C (uncorrected); lH (CDCl3, 200 MHz) 7.65
(d, J=7.6 Hz, 1H) 7.45 (t, J=7.6 Hz, 1H), 7.22 (m, 2H),
3.37 (s, 6H), 3.15 (s, 2H); lC (CDCl3, 50 MHz): 197.1,
149.1, 135.5, 133.5, 127.6, 126.3, 124.6, 101.6, 50.2, 38.1;
GC–EIMS: m/z 192 (M+) (5), 161 (10), 118 (10), 104 (28),
91 (100), 63 (60).
In light of the growing interest in the chemistry of
monoprotected vicinal dicarbonyl compounds,16 the
preparation of similar products using primary alcohols
instead of methanol as protecting reagents is under
way.
Acknowledgements
Financial support from Universita` di Napoli ‘Federico
II’ is gratefully acknowledged.
References
1. Tingoli, M.; Tiecco, M.; Testaferri, L.; Temperini, A.
Synth. Commun. 1998, 28, 1769–1778.
2. De Corso, A. R.; Panunzi, B.; Tingoli, M. Tetrahedron
Lett. 2001, 42, 7245–7247.
3. D’Auria, M.; Mauriello, G. Tetrahedron Lett. 1995, 36,
4883–4884.
4. Tiecco, M.; Testaferri, L.; Bagnoli, L.; Marini, F.; Tem-
perini, A.; Tomassini, C.; Santi, C. Tetrahedron Lett.
2000, 56, 3255–3260.
5. (a) Stavber, S.; Jereb, M.; Zupan, M. Chem. Commun.
2002, 488–489; (b) Jereb, M.; Stavber, S.; Zupan, M.
Synthesis 2003, 853–858.
8. Smith, D. S.; Winnick, J.; Ding, Y.; Bottomley, L. A.
Electrochim. Acta 1998, 43, 335–339.
9. Bringmann, G.; Geisler, J. P. Synthesis 1989, 608–610.
10. In the reaction of 2%,4%-dimethoxyacetophenone com-
pound 5d was consumed and partially phenylselenenyl-
ated on the aromatic ring (<10%).
11. Tiecco, M.; Testaferri, L.; Tingoli, M.; Bartoli, D. J. Org.
Chem. 1990, 55, 4523–4528.
12. Szmant, H. H.; Nanjundiah, R. Org. Prep. Proced. Int.
1977, 9, 35–38.
13. Abbaspou Tehrani, K.; Boeykens, M.; Tyvorskii, V. I.;
Kulinkovich, O.; De Kimpe, N. Tetrahedron 2000, 56,
6541–6548.
14. Carre, M. C.; Gregoire, B.; Caubere, P. J. Org. Chem.
1984, 49, 2050–2052.
15. Tiecco, M.; Testaferri, L.; Tingoli, M.; Bartoli, D.;
Marini, F. J. Org. Chem. 1991, 56, 5207–5210.
16. Tanabe, Y.; Mitarai, K.; Higashi, T.; Misaki, T.; Nishii,
Y. Chem. Commun. 2002, 2542–2543.
6. Buchwald, S. L.; Watson, B. T.; Lum, R. T.; Nugent, W.
A. J. Am. Chem. Soc. 1987, 109, 7137–7141.
7. Typical procedures: (a) Iodination of aromatic ketones:
BTI (1.2 molar equiv.) was added at room temperature to
a solution of ketone (1 mmol) and I2 (0.6 molar equiv.),
in anhydrous CH3CN. The red–brown colour of the
solution disappeared after a few minutes, and all the
reactions described were complete in less than 2 h. After
neutralisation with 0.1 M NaOH solution, the reaction
mixture was extracted with tert-butylmethyl ether,
washed with water and brine and dried over Na2SO4.
Evaporation of the solvent gave the crude material which
after purification on silica gel, using light petroleum as
eluant to remove the iodobenzene derived from the
reduction of BTI, followed by
a mixture of light
petroleum and tert-butylmethyl ether as eluant to recover
the iodo derivatives. (b) Phenylselenenylation of ketones:
in both series of experiments, 0.6 molar equiv. of (PhSe)2