Chemistry Letters Vol.32, No.11 (2003)
1039
aliphatic MOM ethers and esters, which required slightly higher
reaction temperatures and time.
Engl., 35, 2056 (1996).
C. J. Salomon, E. G. Mata, and O. A. Marscaretti, Tetrahe-
dron, 49, 3691 (1993).
P. J. Kocienski, ‘‘Protecting Groups,’’ Georg Thieme, New
York (1994).
T. W. Greene and P. G. M. Wuts, ‘‘Protective Groups in
Organic Synthesis,’’ Wiley, New York (1991), Chap. 2, p 5.
J. Auerbach and S. M. Weinreb, J. Chem. Soc., Chem. Com-
mun., 1974, 298.
2
3
4
5
6
Finally we examined the chemoselective deprotection of ali-
phatic MOM ethers and esters in the presence of other protecting
groups such as phenolic TBDMS, TBDPS, and benzyl ethers
(Entries 7–9). The results were very satisfactory as shown in
Table 1. Similar chemoselective deprotection was also achieved
in the presence of aliphatic TBDPS, benzyl, and allyl ethers (En-
tries 13–15).
Typical procedure: To a stirred solution of the methoxy-
methyl ether of ferulic acid methyl ester (100 mg, 0.44 mmol,
Entry 1) in THF and water (1:1) was added Bi(OTf)3 (1–2 mol
%) at room temperature. The progress of the reaction was moni-
tored by TLC. After the completion of the reaction, the reaction
mixture was filtered, and the filtrate concentrated and subjected
to column chromatography on silica gel using hexane:ethyl ace-
tate (97:3) to afford the pure product.
H. Monti, G. Leandri, M. Klos-Rinquet, and C. Corriol,
Synth. Commun., 13, 1021 (1983).
7R. E. Rieland and M. D. Vamey, J. Org. Chem., 51, 635
(1986).
Y. Quindon, H. E. Morton, and C. Yoakim, Tetrahedron
Lett., 24, 3969 (1983).
M. Shibasaki, Y. Ishida, and N. Okabe, Tetrahedron Lett.,
26, 2217(1985).
8
9
In summary the present procedure of deprotection of MOM
ethers and esters offers salient features such as ease of operation,
high efficiency, environmental-friendly and chemoselectivity.
The deprotection described here adds a new and convenient
method, which may find extensive application in organic synthe-
sis where selective deprotection of MOM ethers is required at
ambient conditions in large scale.
10 R. K. Boeckman Jr. and J. C. Potenza, Tetrahedron Lett., 26,
1407(1985).
11 E. J. Corey, J.-L. Gras, and P. Ulrich, Tetrahedron Lett., 17,
809 (1976).
12 A. S.-Y. Lee, Y.-J. Hu, and S. F. Chu, Tetrahedron, 57, 2121
(2001).
13 A. Kamal, P. S. M. M. Reddy, and D. R. Reddy, Tetrahedron
Lett., 44, 2857(2003) and references cited therein.
14 H. Firouzabadi, I. Mohammadpoor-Baltork, and S. Kolagar,
Synth. Commun., 31, 905 (2001).
The authors are thankful to the Director IICT and Head
Organic Chemistry Division-I for their constant encouragement.
R. J. R thank UGC for providing financial support.
15 T. Oriyama, T. Watahiki, Y. Kobayashi, H. Hirano, and T.
Suzuki, Synth. Commun., 31, 2305 (2001).
16 S. Repichet, A. Zwick, L. Vendier, C. Le Roux, and J.
Dubac, Tetrahedron Lett., 43, 993 (2002).
References
1
M. Schelhas and H. Waldmann, Angew. Chem., Int. Ed.
Published on the web (Advance View) October 13, 2003; DOI 10.1246/cl.2003.1038