G. Bartoli et al. / Tetrahedron Letters 43 (2002) 5945–5947
5947
requested, (ii) co-reagents unneeded, (iii) the extremely
simple experimental procedure, (purification, anhydi-
fication, inert or dry atmosphere are not requested), (iv)
very high deprotection yields, (v) high selectivity
towards TBS group, and (vi) selectivity towards alkyl
TBS group in the presence of aromatic ones. These
advantages are very useful in complex multistep synthe-
ses, which require the sequential protection and depro-
tection of the various functionalities.
gar, D. S. Tetrahedron Lett. 1999, 40, 7293–7294; (e)
Bartoli, G.; Bellucci, M. C.; Bosco, M.; Cappa, A.; Mar-
cantoni, E.; Torregiani, E.; Sambri, L. J. Org. Chem. 1999,
64, 5696–5699; (f) Bartoli, G.; Bosco, M.; Marcantoni, E.;
Nobili, F.; Sambri, L. J. Org. Chem. 1997, 62, 4183–4184.
4. Bartoli, G.; Bosco, M.; Marcantoni, E.; Torregiani, E.;
Sambri, L. Synlett 1998, 209–211.
5. The reaction works also with lower amounts of catalysts,
but longer reaction times are requested. 10% Molar
amount was the better compromise.
6. Berthet, J. C.; Lance, M.; Nierlich, M.; Ephritikhine, M.
Eur. J. Inorg. Chem. 2000, 1969–1973.
7. Zhu, X.; Williams, J. H.; Scott, I. J. Chem. Soc., Perkin
Trans. 1 2000, 2305–2306.
References
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Organic Synthesis, 2nd ed.; John Wiley and Sons: New
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Groups; Georg Thieme: New York, 1994; pp. 21–117; (c)
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9. Between the two t-butyl group signals, only that resonat-
ing at 0.98 ppm is retained in the final product spectrum,
while the signal resonating at 0.91 ppm disappeared. It is
known that aliphatic t-butyl signals are upfielded with
respect to aromatic ones. (Prahash, C.; Saleh, B.; Blair, I.
A. Tetrahedron Lett. 1994, 35, 7565–7568).
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