R. Co´rdoba, J. Plumet / Tetrahedron Letters 43 (2002) 9303–9305
9305
1960, 82, 2402; (b) Johns, J. F. J. Org. Chem. 1966, 31,
3780; (c) Meyer, W. L.; Clemans, G. B.; Manning, R. A.
J. Org. Chem. 1975, 40, 3686; (d) Uemoto, T.;
Kawashima, T.; Sakata, Y.; Misumi, S. Tetrahedron Lett.
1975, 1005; (e) Sharma, V.; Sharma, P. K.; Banerji, K. K.
J. Indian Chem. Soc. 2000, 77, 291; (f) Suri, D.; Banerji,
K. K.; Kothari, S. J. Chem. Res. 1995 (S), 274; (M) 1734;
(g) Goel, S.; Kothari, S.; Banerji, K. K. J. Chem. Res.
1996, (S), 230; (M) 1318; (h) Kothari, S.; Banerji, K. K.
J. Chem. Res. 1999, (S), 476; (M) 2118; (i) Goswami, G.;
Kothari, S.; Banerji, K. K. J. Chem. Res. 1999, (S), 176;
(M) 813.
Scheme 2.
4. Si, A.; Nikalje, M. D.; Sudalai, A. Org. Lett. 1999, 1,
705.
5. (a) Piers, K.; Meimaroglou, C.; Jardine, R. V.; Brown, R.
K. Can. J. Chem. 1963, 41, 2399; (b) Banks, R. E.;
Hasszeldine, R. N.; Latham, J. V.; Young, I. M. J. Chem.
Soc. 1965, 594; (c) Reeves, W. P.; King, R. M., II Synth.
Commun. 1993, 23, 855; (d) Reeves, W. P.; Lu, C. V.;
Sculmeier, B.; Jonas, L.; Hatlevic, O. Synth. Commun.
1998, 28, 499.
Figure 1.
In summary, a new reaction of ipsobromodeformyla-
tion induced by PHPB in pyridine has been described.
This reaction competes with the expected aromatic
bromination when activated o-hydroxy or o-methoxy-
benzaldehyde were subjected to it. In the case of less
activated aromatic aldehydes (2-hydroxy-1-naphtalde-
hyde) the ipsobromodeformylation was the only process
observed.
6. Hinterding, K.; Knebel, A.; Herrlich, P.; Waldmann, H.
Bioorg. Med. Chem. 1998, 6, 1153.
7. It is known that PHPB induces ipsobromodesilylation.
See: (a) Mills, R. J.; Smeckus, V. J. Org. Chem. 1983, 48,
1565; (b) Sibi, M. P.; Shankaran, K.; Alo, B. I.; Hahn,
W. R.; Smeckus, V. Tetrahedron Lett. 1987, 28, 2933.
8. It has been reported that in the reaction of o-methoxy-
Acknowledgements
benzaldehyde with PHPB in
a
mixture of
H2O:AcOH:Et2O (10:40:50), 8% of a ‘monobromination
product’ was obtained. See Ref. 5d. When we carried out
the reaction of this aldehyde with PHPB in pyridine the
starting material was quantitatively recovered.
Ministerio de Ciencia y Tecnolog´ıa (Project BQU 2000-
0653) is gratefully thanked for financial support.
9. Experimental procedure: A solution of pyridinium hydro-
bromide perbromide in pyridine (1 mL/mmol) was added
dropwise to a solution of the aldehyde in pyridine (2
mL/mmol) at 50°C. The reaction was stirred for 2 h at
50°C and then hydrolyzed with ice-water (100 mL/g
aldehyde). After filtration of the precipitate, this was
purified by column chromatography (AcOEt:hexane=1:2
References
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1
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