Phosphorylation of Alkanols
2389
Phosphorylation of ethanol (Table I, run 1). To a suspension of 2.5 g
(
20.1 mmol) of white phosphorus in 100 ml of benzene-ethanol mix-
�
ture (1:1 volume ratio), prepared by rapid cooling to 0–5 C of the hot
�
(
(
50–60 C) emulsion, a solution of 0.5 g (3.7 mmol) of CuCl2 in 14.8 ml
168.9 mmol) of concentrated hydrochloric acid was added. To the ob-
tained mixture, 16.5 ml (160.1 mmol) of 30% aqueous H2O2 was added
dropwise during 1 h upon cooling with ice and stirring. A self-heating
�
of the reaction mixture to 20–22 C was observed and the mixture color
turned from brown to light green. The mixture was stirred for an ad-
ditional 0.5 h at rt. The aqueous layer thus formed was separated and
the organic layer was twice washed with water. After that, water and
unreacted ethanol were removed from the combined aqueous solutions
using a rotary evaporator, the residue was distilled in vacuum and a
�
fraction with b.p.5.0 of 70–80 C was collected. A total of 2.6 g of a mixture
of diethylphosphite and triethylphosphate was obtained. According to
the 31P NMR data, the mixture contained 14% of diethylphosphite (�P
1
0.4 ppm, JP� H 690 Hz) and 11% of triethylphosphate (�P 2.1 ppm).
Phosphorylation of n-butanol (Table I, run 2). To a suspension of 2 g
(
16.1 mmol) of white phosphorus in 100 ml of benzene-n-butanol mix-
�
ture (1:1 volume ratio), prepared by rapid cooling to 0–5 C of the hot
�
(
(
50–60 C) emulsion, a solution of 0.4 g (3.0 mmol) of CuCl2 in 11.8 ml
134.6 mmol) of concentrated hydrochloric acid was added. To the ob-
tained mixture, 13.2 ml (128.1 mmol) of 30% aqueous H2O2 was added
dropwise during 1 h upon cooling with ice and stirring. A self-heating
�
of the reaction mixture to 20–22 C was observed and the mixture color
turned from brown to light green. The mixture was stirred for an ad-
ditional 0.5 h at rt. The aqueous layer thus formed was separated
and the organic layer was twice washed with water. After removal of
the volatile components from the organic phase using a rotary evap-
orator the residue was distilled in vacuum and a fraction with b.p.1.0
�
1
10–130 C was collected. A total of 4 g of a mixture of dibutylphosphite
31
and tributylphosphate was thus obtained. According to the P NMR
data, the mixture contained 18% of dibutylphosphite (�P 10.7 ppm, JP� H
6
83 Hz) and 12% of tributylphosphate (�P 2.3 ppm).
Dibutylphosphite (IIa) (Table I, run 4). To a cooled to 5–10 C mixture
�
of 28.6 g (386.5 mmol) of n-BuOH and 0.6 g (4.4 mmol) of copper(II)
chloride in 30 ml of benzene, a solution of 3 g (24.2 mmol) of white
phosphorus in 120 ml of benzene, and 21.7 g (191.5 mmol) of 30% aque-
ous solution of hydrogen peroxide, preliminarily neutralized with bar-
ium hydroxide to pH = 7, were simultaneously added dropwise using
two dropping funnels during 1.5 h. A self-heating of the reaction mix-
�
ture to 30–35 C was observed and the mixture color turned from dark