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Chehardoli et al.
General Procedure for the Direct Conversion of TMS-ethers to the THP-ethers
To the TMS-ether (1 mmol) and DHP (1.1 mmol) in CH3CN (4 mL) was added {[K.18-
crown-6]Br3}n (0.00054 g, 0.001 mmol) and 1 drop H2O. The solution was stirred at
room temperature for the proper time as determined by TLC (silica gel/n-hexane/
EtOAc) (see Table 1). After completion of the reaction, CH3CN was removed by evap-
oration on the steam bath. Column chromatography on a short pad of silica gel with
CH3CN afforded pure products in good to excellent yields. The catalyst could be regen-
erated via addition of Br2 to the residue of the reaction, followed by recrystallization
from acetonitrile.
Preparation of 2-Phenethoxytetrahydro-2H-pyran (1b)
To a solution of trimethyl(phenethoxy)silane (1a, 0.194 g, 1 mmol) and DHP (0.092 g,
1.1 mmol) in CH3CN (4 mL) was added to {[K.18-crown-6]Br3}n (0.00054 g,
0.001 mmol) and 1 drop H2O. The solution was stirred at room temperature for
20 minutes. CH3CN was removed by evaporation on the steam bath. Column chroma-
tography on a short pad of silica gel with CH3CN afforded 1b, 0.175 g, 85%, colorless
1
oily liquid. IR (KBr): 1021, 1119, 1455 cmꢀ1; HNMR (90 MHz, CDCl3): d¼ 1.62 (br
s, 6H), 2.92 (t, 2H), 3.67(m, 4H), 4.6(s, 1H), 7.25(s, 5H); 13CNMR (22.5 MHz,
CDCl3): d ¼ 14.01, 20.1, 25.27, 31.02, 56.54, 62.81, 93.23, 120.73, 123.59.
Acknowledgments
The authors acknowledge partial support for this work from the Research Affairs
Office of Hamadan University of Medical Sciences, Hamadan, I.R. Iran, and also the
Center of Excellence in the Development of Chemical Methods, Hamedan, I.R. Iran.
ORCID
Gholamabbas Chehardoli
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