SHORT COMMUNICATION
A mild desilylation of phenolic tert-butyldimethylsilyl ethers using in situ
generated tetraethylammonium superoxide
a
b
a
Surabhi Pandey , Ajay K. Shukla , and Raghvendra S. Raghuvanshi
a
b
Department of Chemistry, Faculty of Science, Udai Pratap (Autonomous) College, Varanasi, India; Department of Chemistry, T. D. P. G.
College, Jaunpur, India
ABSTRACT
ARTICLE HISTORY
Desilylation of phenolic tert-butyldimethylsilyl ethers has been achieved under the mild reaction
conditions of in situ generated tetraethylammonium superoxide, at room temperature.
Received 22 February 2021
Accepted 16 June 2021
KEYWORDS
Silyl ethers; deprotection;
superoxide; TBDMS ethers
Introduction
The tert-butyldimethylsilyl (TBDMS) ether has become one
of the most popular silyl protective groups used in organic
synthesis because of its easy installation and their stability to Scheme 1. Deprotection of aryl tert-butyldimethylsilyl ethers.
[
1–3]
a wide variety of reaction conditions.
Although many
methods has been developed for the removal of the TBDMS
group from aliphatic alcohols while the techniques avail- excess of KO with respect to substrate (1) in anhydrous
The reactions were accomplished by using 2.0 fold molar
[
4]
2
able for the cleavage of TBDMS phenolic ethers are rela- DMF. Generally, the substrate phenolic tert-butyldimethyl-
[
2,3,5–14]
tively few.
strong acid, base, and high temperature or ultasound/micro- thylammonium superoxide for 3–6 hours at room
However many of these methods involve silyl ether was allowed to react with in situ generated tetrae-
[
3,6–9]
temperature. The reaction was then quenched with cold
brine solution and then worked up to afford the products in
good to excellent yields (Table 1). The total disappearance
of the starting material was checked by TLC. All the depro-
tection products are known compounds and are identified
by their physical data, IR and NMR spectra, which were in
wave reaction conditions.
O2 ), is a reactive oxygen species (ROS) and plays an
important role in various life processes.
logical important, in organic synthesis, superoxide ion is
mutipotent reagent.
In the light of the above and as a part of the ongoing
research on superoxide chemistry,
results on the reactivity of in situ generated tetraethylammo-
nium superoxide (Et NO ) with different phenolic tert-butyl- Conclusion
The superoxide anion radical
–
ꢀ
(
[
15]
Despite its bio-
[
16,17]
[
19]
full agreement with the values described in the literature.
[
18]
we describe herein our
4
2
dimethylsilyl ethers under non-aqueous conditions at room
temperature, affording corresponding phenols (Scheme 1).
In conclusion, we have established a mild and efficient
method for the desilylation of TBDMS phenolic ethers using
in situ generated tetraethylammonium superoxide.
Results and discussion
Experimental
In the course of reaction (Et N)O was generated in situ by
4
2
the phase transfer reaction of KO and Et NBr in dry DMF
was subsequently allowed to react with phenolic tert-butyldi-
methylsilyl ethers, at room temperature. As an outcome,
2
4
Potassium superoxide and tetraethylammonium bromide
were procured from E. Merck, and were used as received.
Dry DMF of Aldrich, was stored over molecular sieves (4 Å)
phenolic tert-butyldimethylsilyl ethers (1a–g) were readily prior to use. The other reagents and solvent were of A. R.
deprotected to their corresponding phenols (2a–g).
grade. Aryl tert-butyldimethylsilyl ethers were prepared
CONTACT Raghvendra S. Raghuvanshi
Autonomous) College, Varanasi 221002, India.
Department of Chemistry, Faculty of Science, Udai Pratap
(
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