Iranpoor et al.
1011
(0.18 g, 93% yield, bp 226 to 227 °C (lit. value (22) bp 225
to 226 °C).
Typical procedure for the preparation of diethyl ␣-
iodobenzylphosphinate from diethyl ␣-
hydroxybenzylphosphinate using APDPP–NIS
A two-necked flask, equipped with a dropping funnel and
a reflux condenser, was charged with APDPP (0.67 g,
2.3 mmol) and α-hydroxybenzylphosphinate (0.24 g, 1 mmol)
in CH2Cl2 (10 mL) in reflux condition. Then a solution of
N-iodosuccinimide (2.3 mmol) in CH2Cl2 (10 mL) was
added dropwise for a 1.5 h period. TLC monitoring showed
the completion of the reaction after 10 h. After filtration of
the reaction mixture, the residue was chromatographed on a
silica gel column, using n-hexane – ethyl acetate (4:1) as
eluent, to give α-iodobenzylphosphinate (0.31 g, 87% yield).
1H NMR (CDCl3, TMS, 250 MHz, ppm) δ: 3.80–4.08 (m,
2H, 2-OCH2CH3), 4.18–4.27 (m, 2H, 2-OCH2CH3), 4.98 (d,
Typical procedure for the conversion of
benzyltrimethylsilyl ether to benzyl bromide using
APDPP–Br2
To a flask containing a stirring mixture of APDPP (0.35 g,
1.2 mmol) was added Br2 (0.06 mL, 1.2 mmol) at room tem-
perature in dichloromethane (15 mL), after which
benzyltrimethylsilyl ether (0.18 g, 1 mmol) was also added.
TLC monitoring of the reaction showed completion of the
reaction after 1 min. After filtration of the reaction mixture,
enough powdered sodium thiosulfate was added, with vigor-
ous stirring, to react with the unreacted bromine. The reac-
tion mixture was filtered and the solvent was evaporated
under vacuum in a rotary evaporator. The product was
chromatographed on a short silica gel pad (2 cm thick) using
n-hexane as eluent. Benzyl bromide was produced (0.12 g,
95% yield).
2
1H, JPH = 13.4 Hz, -CH), 7.28–7.31 (m, 3H, -C6H5), 7.56–
7.59 (m, 2H, -C6H5). 13C NMR (CDCl3, TMS, 62.9 MHz,
1
3
ppm) δ: 15.41 (d, JCP = 139.9 Hz, -CH), 16.57 (d, JCP
=
3
5.9 Hz, 2-OCH2CH3), 16.7 (d, JCP = 5.9 Hz, 2-OCH2CH3),
64.42 (d, JCP = 8.6 Hz, 2-OCH2CH3), 64.55 (d, JCP
2
2
=
8.6 Hz, 2-OCH2CH3), 128.95–130.04 (-C6H5). MS (70 eV)
m/e: 354 [M], 226 [M – Br], 89 [226 – P(O)(OEt)2]. Anal.
calcd. for C11H16IO3P (%): C 37.29, H, 4.52; found: C 37.5,
H, 4.48.
Typical procedure for the conversion of benzyl-
tetrahydropyranyl ether to benzyl iodide by APDPP–I2
To a stirring mixture of APDPP (0.44 g, 1.5 mmol) and I2
(0.38 g, 1.5 mmol) in CH2Cl2 (10 mL) was added
benzyltetrahydropyranyl ether (0.18 g, 1 mmol) at room
temperature. After 30 min, TLC and GC analysis indicated
that the reaction was complete. The reaction mixture was fil-
tered and the unreacted iodine was removed by the addition,
with vigorous stirring, of enough powdered sodium thio-
sulfate. The mixture was then filtered and the resulting solu-
tion was evaporated. To purify the product, it was passed
through a short column of silica gel using n-hexane – ethyl
acetate as eluent. Benzyl iodide was obtained (0.2 g, 95%
yield). It was identified by comparison with a known sample.
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Typical procedure for the conversion of diethyl ␣-
hydroxybenzylphosphinate to diethyl ␣-
bromobenzylphosphinate using APDPP–Br2
To a flask containing a stirring mixture of APDPP
(2 mmol, 0.58 g) was added Br2 (2 mmol, 0.1 mL) in
CH2Cl2 (7 mL) at room temperature. Then, diethyl α-
hydroxyphosphinate (0.24 g, 1 mmol,) was added. After 6 h,
the reaction mixture was filtered to remove the insoluble
phosphinate and enough powdered sodium thiosulfate was
added to the solution, with vigorous stirring, to react with
the unreacted bromine. After filtration, the product was
washed over a silica gel pad (2 cm thick) using n-hexane –
ethyl acetate (4:1) as eluent to give α-bromophosphinate
1
(0.275 g. 90% yield). H NMR (CDCl3, 250 MHz, ppm) δ:
3
3
1.08 (t, 3H, JHH = 7.1 Hz, 2-OCH2CH3), 1.26 (t, H, JHH
=
7.1 Hz, 2-OCH2CH3), 3.79–4.00 (m, 2H, 2-OCH2CH3),
2
4.03–4.17 (m, 2H, 2-OCH2CH3), 4.79 (d, 1H, JPH
=
14. S.L. Regen and D.P. Lee. J. Org. Chem. 40, 1669 (1975).
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Org. Lett. 4, 1975 (2002).
12.5 Hz, -CH), 7.25–7.28 (m, 3H, -C6H5), 7.47–7.49 (m, 2H,
-C6H5). 13C NMR (CDCl3, TMS, 62.9 MHz) δ: 16.57 (d,
3
3JCP = 5.8 Hz, 2-OCH2CH3), 16.78 (d, JCP = 5.8 Hz, 2-
16. M. Caldarelli, J. Habermann, and S.V. Ley. J. Chem. Soc.
OCH2CH3), 41.85 (d, 1JCP = 159.2 Hz, -CH), 64.46 (d, 2JCP
=
Perkin Trans. 1, 107 (1999).
17. N. Iranpoor, H. Firouzabadi, A. Jamalian, and F. Kazemi. Tet-
rahedron, 61, 5699 (2005).
4.2 Hz, 2-OCH2CH3), 64.57 (d, 2JCP = 4.2 Hz, 2-OCH2CH3),
129.05–129.95, 134.94, 134.99 (-C6H5). MS (70 eV) m/e:
307 [M+], 227 [M – Br], 90 [227 – P(O)(OEt)2]. Anal. calcd. for
C11H16BrO3P (%): C 43.00, H 5.21; found: C 43.10, H, 5.30.
18. L. Desmaris, N. Percina, L. Cottier, and D. Sinou. Tetrahedron
Lett. 44, 7589 (2003).
© 2006 NRC Canada