Beilstein J. Org. Chem. 2011, 7, 426–431.
giving the terminal arylacetylenes in good to excellent yields.
Products phenylacetylene (2f) was a liquid with a boiling
point of 142 °C and 4-bromophenylacetylene (2g) was a solid
that sublimed, consequently some of these compounds were lost
during purification (Table 3, entries 6 and 7). Arylacetylenes 1e
and 1h bearing electron-donating groups showed low reactivity
[22], and the reactions required heating at 75 °C for 15 min then
at 90 °C for 15 min (Table 3, entries 5 and 8). However, the
reaction conditions were still milder than those of existing
methods (>3 h) and satisfactory yields were achieved. It is
worth mentioning that for the 4-aryl-2-methyl-3-butyn-2-ols
containing two or more butynols, complete deprotection was
achieved in only 5–30 min with good yields (Table 3, entries
8–11) using our method, whilst by using the conventional
method deprotection was incomplete or the yields were low, or
longer reaction times were required [22-25]. For example,
multifunctional arylacetylenes 2i and 2k were prepared in 85%
and 83% yields in 5 min (Table 3, entries 10 and 11), whereas
they were obtained in only 38% and 11% yields in 8 h, respect-
ively, when sodium was used in refluxing toluene (Supporting
applications for the preparation of arylacetylene dendritic
macromolecules in high yield.
Supporting Information
Supporting Information File 1
General experimental methods, analytical data, 1H and
13C NMR spectra of compounds 1a–k and 2a–k.
References
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General procedure for the deprotection reaction using
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430