1678
S. C. Roy, B. Banerjee
LETTER
(5) Frick, J. G. Jr.; Harper, R. J. Jr. J. Appl. Polym. Sci. 1984, 29,
1433.
Table 1 Diacetoxylation of Aldehydes Using Acetic Anhydride Ca-
talysed by CAN and their Deprotection with CAN and Water
(6) Eanderson, W. R. Eur. Pat. Appl. EP 125, 781, 1985; Chem.
Abstr. 1985, 103, P64010K.
(7) Lieberman, S. V.; Connor, R. Org. Synth., Coll. Vol. II 1951,
441.
(8) Sydnes, L. K.; Sandberg, M. Tetrahedron 1997, 53, 12679;
and references cited therein.
Entry Starting Material
Yield (%)a of Yield (%)a of
Acylals
Deprotection
90 (4 h)b
90 (4.5 h)
87 (4.5 h)
90 (4.5 h)
90 (4.5 h)
91 (5.5 h)
88 (5.5 h)
86 (4 h)
1
2
Benzaldehyde
95 (1.5 h)b
90 (26 h)
92 (6 h)
4-Methoxybenzaldehyde
3-Methoxybenzaldehyde
Piperonal
(9) (a) Bandgar, B. P.; Mahajan, N. P.; Mulay, D. P.; Thote, J.
L.; Wadgaonkar, P. P. J. Chem. Res., Synop. 1995, 470.
(b) Raju, S. V. N. J. Chem. Res., Synop. 1996, 68, 470.
(c) Aggarwal, V. K.; Fonquerna, S.; Vennall, G. P. Synlett
1998, 849. (d) Deka, N.; Kalita, D. J.; Borah, R.; Sarma, J.
C. J. Org. Chem. 1997, 62, 1563. (e) Chandra, K. L.;
Saravanan, P.; Singh, V. K. Synlett 2000, 359. (f) Karimi,
B.; Seradj, H.; Ebrahimian, G. R. Synlett 2000, 623.
(g) Carrigan, M. D.; Eash, K. J.; Oswald, M. C.; Mohan, R.
S. Tetrahedron Lett. 2001, 42, 8133. (h) Sumida, N.;
Nishioka, K.; Sato, T. Synlett 2001, 1921.
(10) (a) Knoevenagel, E. Liebigs Ann. Chem. 1914, 402, 111.
(b) Cymerman-Craig, J.; Willis, D. J. Chem. Soc. 1955,
1071. (c) Scriabine, I. Bull. Soc. Chim. Fr. 1961, 1194.
(d) Trost, B. M.; Lee, C. B.; Weiss, J. M. J. Am. Chem. Soc.
1995, 117, 7247. (e) Trost, B. M.; Lee, C. B. J. Am. Chem.
Soc. 2001, 123, 3671; and references cited therein. (f) Fry,
A. J.; Rho, A. K.; Sherman, L. R.; Sherwin, C. S. J. Org.
Chem. 1991, 56, 3283. (g) Bhatia, B.; Punniyamurthy, T.;
Iqbal, J. J. Org. Chem. 1993, 58, 5518. (h) Man, E. H.;
Sanderson, J. J.; Hause, C. R. J. Am. Chem. Soc. 1950, 172,
847. (i) Kumar, P.; Hegde, V. R.; Kumar, T. P. Tetrahedron
Lett. 1995, 36, 601. (j) Pereira, C.; Gigante, B.; Marcelo-
Curto, M. J.; Carreyre, H.; Perot, G.; Guisnet, M. Synthesis
1995, 1077.
3
4
86 (24 h)
97 (4 h)
5
4-Chlorbenzaldehyde
Vanilin
6
94 (28 h)
90 (22 h)
85 (23 h)
96 (24 h)
94 (4.5 h)
75 (4 h)
7
3-Hydroxybenzaldehyde
Furfural
8
9
4-Nitrobenzaldehyde
1-Naphthaldehyde
Acrolein
89 (7 h)c
90 (5 h)
10
11
12
13
14
15
86 (4.5 h)
87 (4 h)
Crotonaldehyde
Cinnamaldehyde
Valeraldehyde
91 (2.5 h)
96 (6 h)
91 (4 h)
70 (28 h)
70 (32 h)
90 (4.5 h)
89 (4 h)
Caproaldehyde
a Yields to refer to chromatographically pure isolated product.
b Reaction time within parenthesis.
(11) (a) Olah, G. A.; Mehrotra, C. S. Synthesis 1982, 962.
(b) Jin, T. S.; Du, G. Y.; Zhang, Z. H.; Li, T. S. Synth.
Commun. 1997, 27, 2261. (c) Li, T.-S.; Zhang, Z. H.; Fu, C.-
G. Tetrahedron Lett. 1997, 38, 3285.
(12) Yadav, J. S.; Subba Reddy, B. V.; Srinivas, C. Synth.
Commun. 2002, 32, 1175.
c 1.1 Equiv of CAN used.
sponding aldehydes in excellent yields using a catalytic
amount of CAN and water at 70 °C.
(13) General Procedure for Acylation: A solution of the
aldehyde (1.13 mmol) in distilled acetic anhydride (2.26
mmol) was stirred with CAN (10 mol%) at r.t. under N2. The
progress of the reaction was monitored by TLC. After
completion of the reaction, the mixture was quenched with
sat. aq NaHCO3 solution (4 mL) and was extracted with
ether (3 25 mL). The combined organic layer was
successively washed with sat. aq NaHCO3 solution (3 10
mL), water (15 mL) and brine (20 mL) and then dried
(Na2SO4). The solvent was removed under reduced pressure
and the residue obtained that was column chromatographed
over silica gel to obtain the pure acylal.
(14) General Procedure for Deprotection: A mixture of the
acylal (1.0 mmol), CAN (10 mol%), water (2 mL) in
acetonitrile (2 mL) was stirred at 70 °C under N2. The
progress of the reaction was monitored by TLC. After
completion of the reaction, the mixture was diluted with
brine (10 mL), extractited with ether (3 20 mL). The
combined ether extract was washed with sat. aq NaHCO3
solution (3 10 mL) and dried (Na2SO4). Solvent was
removed under reduced pressure and the residue obtained
was column chromatographed over silica gel to obtain the
pure aldehyde.
Acknowledgement
We are thankful to the Department of Science & Technology, New
Delhi for financial assistance. B.B. thanks to CSIR, New Delhi for
the award of a Junior Research Fellowship.
References
(1) (a) Gregory, M. J. J. Chem. Soc. B 1970, 1201. (b) Greene,
T. W.; Wuts, P. G. M. Protective Groups in Organic
Synthesis, 3rd ed.; John Wiley and Sons: New York, 1999,
306.
(2) Kochhar, K. S.; Bal, B. S.; Deshpande, R. P.; Rajadhyaksha,
S. N.; Pinnick, H. W. J. Org. Chem. 1983, 48, 1765.
(3) (a) Saucy, G.; Marbet, R.; Lindlar, H.; Isler, O. Helv. Chim.
Acta 1959, 42, 1945. (b) Blanc, P.-Y. Helv. Chim. Acta
1961, 44, 1. (c) Snider, B. B.; Amin, S. G. Synth. Commun.
1978, 8, 117. (d) McDonald, E.; Suksamrarn, A.; Wylie, R.
D. J. Chem. Soc., Perkin Trans. 1 1979, 1983. (e) Banks, R.
E.; Miller, J. A.; Nunn, N. J.; Stanley, P.; Weakley, T. J. R.;
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(4) (a) Whitesides, G. M.; Filippo, J. S. Jr. J. Am. Chem. Soc.
1970, 92, 6611. (b) Held, H.; Rengstl, A.; Mayer, D. In
Ullmann’s Encyclopedia of Industrial Chemistry, 5th ed.,
Vol. A1; Gerhartz, W., Ed.; VCH: New York, 1985, 68.
(15) All the acylals prepared and the aldehydes obtained by the
deprotection of the alylals were fully characterised by 1H
NMR and IR study and comparing the spectral data with
those of authentic samples.
Synlett 2002, No. 10, 1677–1678 ISSN 0936-5214 © Thieme Stuttgart · New York