Synthesis of chiral tert-butylphenylphosphine oxide [2]

Full text of DOI:10.1023/B:RUGC.0000018664.98642.48

Russian Journal of General Chemistry, Vol. 73, No. 11, 2003, pp. 1823 1824. Translated from Zhurnal Obshchei Khimii, Vol. 73, No. 11, 2003,
pp. 1924 1925.
Original Russian Text Copyright
2003 by Grishkun, Kolodyazhnaya, Kolodyazhnyi.
LETTERS
TO THE EDITOR
Synthesis of Chiral tert-Butylphenylphosphine Oxide
E. V. Grishkun, A. O. Kolodyazhnaya, and O. I. Kolodyazhnyi
Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, Kiev, Ukraine
Received July 24, 2002
Reaction of racemic t-butylphenylchlorophosphine
I with (S)-(1-phenylethyl)amine II yields diastereo-
merically enriched (1-phenylethylamino)(t-butyl)-
phenylphosphine III [1, 2], which after treatment with
borane in THF produces diastereomerically pure
aminophosphine borane complex IV.
*
t-Bu
t-Bu
t-Bu
R NH2/B t-Bu
H B THF
Et NH
2
II
3
H B --- P NHR*
P ~~~ N H R *
P NHR*
P ~~~ C l
3
Ph
Ph
.
.
.
..
.
..
Ph
Ph
I
(RP+Sp)-III
R* = (S)-CH(Me)Ph.
IV
(Rp)-III
Complex IV was purified by recrystallization from
at weak cooling. The reaction mixture was kept for
12 h at room temperature. Triethylamine hydrochlo-
ride was filtered off, the mother liquor was concen-
trated, and the residue was distilled in a vacuum.
1
13
31
hexane. A H, C, and P NMR study showed that
complex IV is 100% diastereomerically pure. De-
complexation of IV by treatment with excess diethyl-
amine (50 C, 24 h) gave diasteremerically pure start-
1
Yield 75%, bp 130 135 C (0.02 mm). H NMR spec-
3
1
3
ing aminophosphine III ( 100% according to P and
trum (CDCl3), , ppm (J, Hz): 0.81 d ( J 7.0,
HP
1
3
H NMR spectra).
CH C), 1.60 m (NH), 1.45 d [(CH ) C, J 14.0],
3
3 3
HH
3
1
3
.54 m (CHN), 7.10 7.33 m (C H ). P NMR spec-
6 5
Acidolysis of (1-phenylethylamino)(t-butyl)phenyl-
phosphine III with formic acid in toluene yielded
optically active (S)-( )-t-butylphenylphosphine oxide
V. The optical rotation and other physicochemical
characteristics of compound V synthesized by us are
identical to those of (S)-( )-t-butylphenylphosphine
oxide described in the literature [3 5].
trum (CDCl3), P, ppm: 49.00. Found P, %: 10.66.
C H NP. Calculated P, %: 10.85.
1
8
24
(
SP,S)-(1-Phenylethylamino)(t-butyl)phenyl-
phosphine borane complex IV. A solution of
.01 mol of borane in THF was added dropwise with
0
cooling to 0 C to a solution of 2.85 g of III in 5 ml
of THF. The mixture was left for 12 h at room tem-
perature, the solvent was evaporated, and the crystal-
line residue was recrystallized from hexane. Yield
O
HCO H
2
III
P
.
H
80%, mp 140 141 C (hexane). [ ] +24.5 (c 0.01,
Ph
.
.
D
.
.
1
CH Cl ). H NMR spectrum (CDCl ), , ppm (J, Hz):
t-Bu
2
2
3
3
0
(
(
.2 2 m (BH ), 1.01 d [(CH ) C, J 14.16], 1.50 d
3 3 3 HP
V
3
2
CH , J 6.72), 2.07 br.d (NH, J 16.0), 4.45 m
3 HH HP
1
3
CHN), 7.10 7.40 m (C H ). C NMR spectrum
6
5
2
(
R ,S)-(1-phenylethylamino)(t-butyl)phenyl-
(CDCl3), , ppm (J, Hz): 24.57 d [(CH ) C, J
P
C 3 3 CP
3
phosphine III. A solution of 1.272 g (0.0105 mol) of
2.76], 25.57 d (CH CHN, JCP 5.20), 30.69 d
3
1
2
1
-phenylethylamine and 1.06 g (0.0105 mol) of tri-
[(CH ) C, J 43.40], 52.47 d (CHN, J 2.01),
3 3 CP CP
ethylamine in 5 ml of benzene was added to a solution
of 2 g of t-butylchlorophosphine in 10 ml of benzene
126.10 s, 126.94 s, 127.58 d (JCP 9.50), 130.37 d (JCP
2.50), 130.75 d (JCP 46.80), 131.94 d (JCP 9.40)
1
070-3632/03/7311-1823$25.00 2003 MAIK Nauka/Interperiodica

1
824
GRISHKUN et al.
85% H PO in D O ( P). The optical rotation was
3
1
31
(C H ). P NMR spectrum (CDCl ), P, ppm (J, Hz):
6
5
3
3
4
2
1
6
9.76 br.d ( J 42.93) (cf. [6]). Found, %: N 4.61;
measured on a Perkin Elmer instrument.
BP
P 10.34. C H BNP. Calculated, %: N 4.68; P 10.35.
1
8
27
REFERENCES
(
S)-( )-t-Butylphenylphosphine oxide V. A
0
.02-mol portion of formic acid was added at 0 C to
1
. Kolodiazhnyi, O.I., Tetrahedron: Asymmetry, 1998,
vol. 9, no. 8, p. 1279.
1
.42 g of III dissolved in toluene. The reaction
3
1
progress was monitored by P NMR spectroscopy.
When the reaction was complete, the volatiles were
removed, and the product was extracted with ether and
hexane, and additionally purified by passing through
a short column packed with deoxygenated silica gel
2. Kolodiazhnyi, O.I., Advances of Asymmetric Synthesis,
Hassner, A., Ed., Stamford: JAI, 1998, vol. 3, p. 273.
3
4
. Skrzypczynski, Z. and Michalski, J., J. Org. Chem.,
988, vol. 53, no. 19, p. 4549.
1
(
the product is readily oxidized with atmospheric
. Drabowicz, J., Lyzwa, P., Omelanczuk, J., Pietrusie-
wicz, K.M. and Mikolajczyk, M., Tetrahedron: Asym-
metry, 1999, vol. 10, no. 14, p. 2757.
oxygen). Yield 50%, [ ]D 44.6 (c 1, toluene) {agrees
with the data for the previously obtained compound
1
[
3 5]: [ ]D 40.45 (c 1.78, MeOH)}. H NMR spec-
trum (CDCl ), , ppm (J, Hz): 1.018 d [(CH ) C, J
5. Haynes, R.K., Freeman, R.N., Mitchel, C.R., and
Vonwiller, S.C., J. Org. Chem., 1994, vol. 59, no. 11,
p. 2919.
3
3 3
HH
7], 7.05 7.95 m (C H ), 5.29 d (PH, J 454). 31P
1
1
6 5 PH
NMR spectrum (CDCl ), P, ppm (J, Hz): 48.17 d
3
1
(
JPH 454).
6. Imamoto, T., Oshiki, T., Onozawa, T., Kusumoto, T.,
and Sato, K., J. Am. Chem. Soc., 1990, vol. 112, no. 13,
p. 5244.
NMR studies were performed on a Varian-300
1
13
instrument, internal reference TMS ( H and C) and
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 73 No. 11 2003