8398
S. Bhatt, S. K. Nayak / Tetrahedron Letters 47 (2006) 8395–8399
yielded 4-(tert-butyldimethylsilyloxymethyl)phenol 20 in
9% yield as the major product along with a small
amount (17%) of 4-tert-butyldimethylsilyloxy benzyl
alcohol 21 (the NMR data of which was identical with
5. Corey, E. J.; Roberts, B. E. J. Am. Chem. Soc. 1997, 119,
2425–12431.
1
5
6
. Furstner, A.; Albert, M.; Mlynarski, J.; Metheu, M.;
DeClerq, E. J. Am. Chem. Soc. 2003, 125, 13132–13142.
. Shahid, K. A.; Mursheda, J.; Okazaki, M.; Shuto, Y.;
Goto, F.; Kiyooka, S. Tetrahedron Lett. 2002, 43, 6377–
7
that obtained from the NaBH reduction of 4-tert-butyl-
4
dimethylsilyloxybenzaldehyde) (entry 9). This clearly
indicates that deprotection of aryl-TBDMS ethers is
6
381.
8
. Jackson, S. R.; Johnson, M. G.; Mikami, M.; Shiokawa,
faster than that of alkyl-TBDMS ethers with CuBr2.
S.; Carreira, E. M. Angew Chem., Int. Ed. 2001, 40, 2694–
2
697.
In conclusion, CuBr has been demonstrated to be a con-
9. Yang, Y.-Y.; Yang, W.-B.; Teo, C.-F.; Lin, C.-H. Synlett
2000, 1634–1636.
0. Oriyama, T.; Kobayashi, Y.; Noda, K. Synlett 1998,
2
venient deprotecting reagent for TBDMS ethers of alco-
hols/phenols. The advantages of the method are: (i) the
use of a catalytic amount of an inexpensive reagent, (ii)
simple experimental procedure, (iii) high chemoselectiv-
ity in the presence of ketal, allyl, benzyl, TBDPS and
THP ethers and alkene functionalities and (iv) selectivity
towards aryl-TBDMS ethers in the presence of aliphatic
ones. These facets are very useful in complex multistep
synthesis, which requires the sequential protection and
deprotection of various functionalities.
1
1
047–1048.
1
1. Bartoli, G.; Cupone, G.; Dalpozzo, R.; Nino, A. D.;
Maiuolo, L.; Procopio, A.; Sambri, L.; Tagarelli, A.
Tetrahedron Lett. 2002, 43, 5945–5947.
1
1
2. Jadav, J. S.; Reddy, B. V. S.; Madan, C. New J. Chem.
2
000, 24, 853–854.
3. Crouch, R. D.; Polizzi, J. M.; Cleiman, R. A.; Yi, J.;
Romany, C. A. Tetrahedron Lett. 2002, 43, 7151–7153.
14. Ranu, B. C.; Jana, U.; Majee, A. Tetrahedron Lett. 1999,
0, 1985–1988.
4
1
1
1
5. Bartoli, G.; Bosco, M.; Marcantoni, E.; Sambri, L.;
Typical experimental procedure: A solution of a TBDMS
Torregiani, E. Synlett 1998, 209–210.
6. Bajwa, J. S.; Vivelo, J.; Slade, J.; Repic, O.; Blacklock, T.
Tetrahedron Lett. 2000, 41, 6021–6024.
7. Crouch, R. D.; Romany, C. A.; Kreshock, A. C.;
Menkoni, K. A.; Zile, J. L. Tetrahedron Lett. 2004, 45,
ether of alcohol/phenol (2.0 mmol) and CuBr (0.6 mmol,
2
0
.135 g, 30 mol %) in dry acetonitrile (10 mL) was stirred
at room temperature for the appropriate amount of time
Tables 2 and 3). After completion of the reaction, as indi-
(
cated by TLC, the reaction mixture was concentrated,
quenched with water and ethyl acetate (10 mL) and
passed through a Celite bed. The Celite was washed with
ethyl acetate (2 · 5 mL). The organic layer was washed
with water and, brine and then dried (Na SO ). Removal
1
279.
1
8. Jang, J.-Y.; Wang, Y.-G. Tetrahedron Lett. 2003, 44,
3859–3861.
19. Lee, A. S.-Y.; Yeh, H.-C.; Shie, J.-J. Tetrahedron Lett.
1998, 39, 5249–5252.
2
4
2
0. Lipshutz, B. H.; Keith, J. Tetrahedron Lett. 1998, 39,
495–2498.
of the solvent followed by preparative thin layer chroma-
tography afforded the respective alcohol/phenol.
2
2
1. Hwu, J. R.; Jain, M. L.; Tsai, F.-Y.; Tsay, S.-C.;
Balkumar, A.; Hakimelahi, G. H. J. Org. Chem. 2000,
65, 5077–5088.
All the products were characterized from their spectro-
1
13
scopic data (IR, H, C NMR and MS). The data for
known compounds are in good agreement with those
reported. Spectroscopic and analytical data for selected
2
2. Semwal, A.; Nayak, S. K. Synth. Commun. 2006, 36, 227–
2
36.
2
3. Nayak, S. K. Synth. Commun. 2006, 36, 1307–1315.
24. Kodomari, M.; Satoh, H.; Yoshitomi, S. Bull. Chem. Soc.
Jpn. 1988, 61, 4149–4150.
2
8
compounds are provided.
2
2
5. Crouch, R. D. Tetrahedron 2004, 60, 5833–5871.
6. Castro, C. E.; Gaughan, E. J.; Owsley, D. C. J. Org.
Chem. 1965, 30, 587–592.
Acknowledgement
2
7. Bauer, D. P.; Macomber, R. S. J. Org. Chem. 1975, 40,
1990–1993.
One of the authors (S.B.) is thankful to the Department
of Atomic Energy, Government of India for the finan-
cial support in the form of a junior research fellowship.
28. Spectral data of selected compounds: (E)-1,2-Bis(4-tert-
butyldimethylsilyloxyphenyl)ethene 8: solid. Mp 69–70 ꢁC,
IR (KBr): m = 3064, 3028, 2956, 2930, 2886, 2858, 1598,
À1
1
1
489, 1281, 921, 830 cm . H NMR (200 MHz, CDCl
3
):
d = 7.26 (d, 4H, J = 8.5 Hz), 6.81 (s, 2H), 6.71 (d, 4H,
1
3
J = 8.5 Hz), 0.89 (s, 18H), 0.11 (s, 12H). C NMR
50 MHz, CDCl ): d = 155.0, 130.8, 127.3, 123.3, 120.3,
References and notes
(
3
+
2
1
9
5.7, 18.2, 4.4. MS (EI): m/z 441 (M + H ), 384, 326, 253,
62, 116, 72, 57. Anal Calcd for C H O Si : C 70.85, H
.15. Found: C 70.68, H 9.01. (E)-1-(4-tert-Butyldimeth-
ylsilyloxyphenyl)-2-(4-hydroxyphenyl)ethene 9: solid. Mp
2–84 ꢁC; IR (KBr): m = 3604, 3400, 3019, 2957, 2930,
858, 1607, 1512, 1471, 1463, 1256, 1216, 1169, 911, 838,
3
58 cm . H NMR (200 MHz, CDCl ): d = 7.37 (d, 4H,
J = 8.0 Hz), 6.91 (s, 2H), 6.82 (m, 4H), 1.00 (s, 9 H), 0.22
): d = 154.9, 154.8,
30.9, 130.5, 127.5, 127.2, 126.1, 120.2, 115.5, 25.6, 18.1,
.5. MS (EI): m/z 326 (M ), 213, 195, 165, 154, 118, 89.
Si: C 73.57, H 8.03. Found: C
3.69, H 8.21. 4-(tert-Butyldimethylsilyloxy)-5,6-cyclo-
1
. (a) Greene, T. W.; Wuts, P. G. M. Protective Groups in
Organic Synthesis, 3rd ed.; John Wiley & Sons: Wiley:
New York, 1999; p 17; (b) Kocienski, P. Protecting
Groups, 1st ed.; George Thieme: Stuttgart, 1994; (c)
Sandler, S. R.; Karo, W. Organic Functional Group
Preparation; Academic Press: San Diego, 1989; pp 430–
81.
. Corey, E. J.; Venkateswarlu, A. J. Am. Chem. Soc. 1972,
4, 6190–6192.
. Fukuda, Y.; Shindo, M.; Shishido, K. Org. Lett. 2003, 5,
49–751.
. Nakamura, T.; Shiozaki, M. Tetrahedron Lett. 2001, 42,
701–2704.
26 40
2
2
8
2
7
À1
1
4
2
3
4
1
3
(
s, 6H). C NMR (50 MHz, CDCl
3
9
1
4
+
7
26 2
Anal. Calcd for C20H O
7
2