Double asymmetric induction in the addition reaction of chiral phosphites to C=N compounds

Full text of DOI:10.1023/A:1012312325228

Russian Journal of General Chemistry, Vol. 71, No. 6, 2001, pp. 977 978. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 6, 2001,
pp. 1039 1040.
Original Russian Text Copyright
2001 by Kolodyazhnyi, Sheiko.
LETTERS
TO THE EDITOR
Double Asymmetric Induction in the Addition Reaction
of Chiral Phosphites to C=N Compounds
O. I. Kolodyazhnyi and S. Yu. Sheiko
Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, Kiev, Ukraine
Received August 3, 2000
We found that using two asymmetric inductors,
instead of one, in the addition reaction of C=N com-
pounds I and chiral phosphites II, III considerably
favors a much more stereoselective reaction.
HO
Ph
(RO)2P(O)H
RO
Ph
HCl/dioxane
II
P
H
HO
H
P
RO
H2/Pd C
DBU
O
O
NHCH(Me)Ph
NH2
H
N
V
Ph
IV
Ph
(SR), 100% de
(+)-(S), 100% ee
H
Me
O
NH2
H
(RO)3P
III
O
NHCH(Me)Ph
I
HCl/dioxane
H2/Pd C
P
P
HO
HO
RO
RO
H
( )-(R)
BF3 Et2O
Ph
Ph
VI
VII
(RR), 70% de
( )-(R)
R = (1S,2S,5R)-2-menthyl, DBU = diazabicycloundecene.
Thus, addition of chiral hydrogen di[(1R,2S,5R)-2-
menthyl] phospite (II) to chiral (R)- -methylbenzyl-
benzaldimine (I) in the presence of a catalytic amount
of diazabicycloundecene (DBU) results in a single
diastereomer of N-substituted aminophosphonic
diester V. The 31P {1H} NMR analysis of crude
crystalline reaction products revealed no second dia-
stereomer. For comparison, similar reactions of chiral
phospite II with achiral benzylbenzaldimine and of
achiral diethyl hydrogen phosphite with chiral (S)- -
methylbenzylbenzaldimine result in a 30-45% dia-
stereomeric excess of aminophosphonic diesters [1, 2].
The configuration of the compounds was deter-
mined chemically. Initially, the menthyl groups were
removed from the phosphorus atom by hydrolysis of
the diesters with hydrochloric acid. Then the -me-
thylbenzyl group was eliminated under the action of
gaseous hydrogen in the presence of palladium on
carbon. As a result, monochiral stereoisomers V and
VII were obtained, and their configuration was
elucidated from a comparison of their optical rotation
angles with those of earlier described R- and S- -
aminobenzylphosphonic acids [4].
We found that reaction of hydrogen di[(1R,2S,5R)-
2-menthyl] phosphite (II) with (R)- -methylbenzyl-
benzaldimine results in formation of (S)- -amino-
benzylphosphonic acid, while trimethyl phosphite with
(R)- -methylbenzylbenzaldimine gives (R)- -amino-
benzylphosphonic acid.
Reaction of tri[(1R,2S,5R)-2-menthyl] phospite
(III) with I, too, occurs with a much higher stereo-
control (up to 70%). Earlier we showed that the asym-
metric induction of the reaction of chiral phosphite
III with achiral benzylbenzaldimines is no more than
30 50% [3].
1070-3632/01/7106-0977$25.00 2001 MAIK Nauka/Interperiodica

978
KOLODYAZHNYI, SHEIKO
The reaction described in this communication is
NMR spectrum (D2O), , ppm: 7.28 s (5H, C6H5),
4.25 d (1H, PCH, JHP 17 Hz).
probably the first example of double asymmetric in-
duction involving organophosphorus compounds. Of
particular importance are the high yield of the reaction
and the high optical purity of its products, which
allows to preparation, on a multigram scale, of
(R)- -Aminobenzylphosphonic acid (VII). Hydro-
chloride. Yield 90%, mp 226 C, [ ]2D0 = +20 (c 0.32,
0.1 N aqueous NaOH). The product is similar to ear-
lier described (+)-(R)-[(amino)phenymethyl]phos-
phonic acid, [ ]2D0 = +19 (c 1, 0.1 N aqueous NaOH)
enaniomerically pure
-aminophosphonic acids
without use of fractional crystallization or chromato-
graphy.
1
[4]. H NMR spectrum (D2O), , ppm: 7.28 s (5H,
C6H5), 4.25 d (1H, PCH, JHP 17 Hz).
Di[(1R,2S,5R)-2-menthyl] (RS)-[( -phenyl-
ethylamino)phenylmethyl]phosphonate (IV). Yield
80% (100% before crystallization), mp 128 C
The NMR spectra were obtained on Varian
(300 MHz) and JEOL (90 MHz) instruments in deu-
terated solvents, external reference 85% phosphoric
acid (31P NMR).
20
(acetone), [ ]D
trum (CDCl3):
68.0 (c 1, toluene). 31P NMR spec-
21.94 ppm. 1H NMR spectrum
(CDCl3), , ppmP (J, Hz): 0.5 m (menthyl group),
0.75 1.05 m (18H, menthyl CH3 groups), 1.28 d (3H,
CH3CH, JHH 6.5), 1.0 2.0 m (16H, CH2 + CH),
3.82 q (1H, CHCH3, JHH 6.4), 4.2 d (1H, CHP, JHP
16.7), 4.3 m (1H, NH), 7.25 m (10H, C6H5). Mass
spectrum (70 eV): m/z 568 (M+). Found, %: P 5.34.
C35H54NO3P. Calculated, %: P 5.45.
ACKNNOWLEDGMENTS
The work was financially supported by the Ukra-
inian Foundation for Basic Research (project
no. 3.04/0188) and by the SPECS Ukrainian-Holland
Joint-Stock Company.
REFERENCES
Di[(1R,2S,5R)-2-menthyl] (RR)-[( -phenyl-
ethylamino)phenylmethyl]phosphonate (VI). Yield
65%, mp 132.5 C (hexane), [ ]2D0 88.0 (c 1, to-
1. Kolodiazhnyi, O.I., Tetrahedron: Asymmetry, 1998,
vol. 9, no. 8, pp. 1279 1332.
luene). 31P NMR spectrum (CDCl3):
22.05 ppm.
2. Kolodiazhnyi, O.I., Grishkun, E.V., Sheiko, S., Dem-
chuk, O., Thoennessen, H., Jones, P., and Schmutz-
ler, R., Tetrahedron: Asymmetry, 1998, vol. 9, no. 10,
pp. 1645 1648.
Mass spectrum (70 eV): m/z 568 (M+).PFound, %: P
5.38. C35H54NO3P. Calculated, %: P 5.45.
(S)- -Aminobenzylphosphonic acid (III). Hydro-
chloride. Yield 90%, mp 226 C, [ ]2D0 = +20 (c 0.32,
0.1 N aqueous NaOH). The product is similar to earli-
er described ( )-(S)-[(amino)phenylmethyl]phosphonic
3. Kolodiazhnyi, O.I., Sheiko, O., and Grishkun, E.V.,
J. Heteroatom. Chem., 2000, vol. 11, no. 2, pp. 138 143.
4. Kafarski, P., Lejczak, B., and Szewczyk, J., Can. J.
Chem., 1983, vol. 61, p. 2425.
acid, [ ]2D0 = 19 (c 1, 0.1 N aqueous NaOH) [4]. H
1
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 6 2001