Enantioselective addition of dimenthyl and dibornyl phosphites to schiff bases

Full text of DOI:10.1023/A:1013194829987

Russian Journal of General Chemistry, Vol. 71, No. 7, 2001, pp. 1155 1156. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 7, 2001,
pp. 1225 1226.
Original Russian Text Copyright
2001 by Kolodyazhnyi, Sheiko.
LETTERS
TO THE EDITOR
Enantioselective Addition of Dimenthyl
and Dibornyl Phosphites to Schiff Bases
O. I. Kolodyazhnyi and S. Sheiko
Institute of Bioorganic and Petroleum Chemistry, National Academy of Sciences of the Ukraine, Kiev, Ukraine
Received June 21, 2000
Recently we described CN-symmetrical chiral
esters of phosphorous acid, prepared from cheap
optically active natural alcohols (menthol, borneol,
glucofuranose, etc.) [1 3]. These compounds are
convenient asymmetric inductors in additions to C=N,
C=O, and C=C bonds [4 6]. In the present work we
found that replacement of the (1R, 2S, 5R)-menthyl
groups on the phosphorus atom of dialkyl phosphites
by (1S)-endo-bornyl changes the configuration of the
stereogenic center on the -carbon atom of amino-
phosphonic acids.
Mnt = (1R,2S,5R)-mentyl, Brn = (1S)-endo-bornyl; R = Brn (a), Mnt (b).
Dialkyl phosphites I react with benzylaminoaniline
at 80 C, affording diesters of substituted aminophos-
phonic acids with preference for R diastereomer IIa
(R = Mnt) S diastereomer IIb (R = Brn). One or two
crystallizations give absolutely pure diastereomers IIa
and IIb. Their structure was confirmed by NMR
spectra, and configuration, by chemical transforma-
tions. Compounds II were converted to aminophos-
phonic acids IV whose configuration is known. First,
by hydrolysis of diesters II with hydrochloric acid in
dioxane we obtained S- and R-N-benzyl-1-aminoben-
zylphosphonic acids and measured their optical rota-
tion, [ ]D, deg (c 0.3, DMSO): IIIa +26 and IIIb 26.
Then compounds III were subjected to catalytic re-
duction with hydrogen in the presence of palladium
on charcoal to obtain (S)- and (R)-IV whose confi-
guration was established by comparison with the
previously described (S)- and (R)-1-aminobenzyl-
phosphonic acid hydrochlorides [6] and sodium salts
20
578
[7, 8]: (R)-IV [ ] +18.1 (c 1, 1 N aqueous NaOH)
and (R)-IV HCl [ ]D 20 (c 0.3, DMSO). The S
configuration of dibornyl ether IIb was established by
X-ray diffraction [3].
Di-(1S)-endo-bornyl [(S)- -(benzylamino)-
benzyl]phosphonate (IIa). Yield 60%, mp 144 C,
1070-3632/01/7107-1155$25.00 2001 MAIK Nauka/Interperiodica

1156
KOLODYAZHNYI, SHEIKO
[ ]2D0 47 (c 1.0, toluene). 1H NMR spectrum
(CDCl3) , ppm (J, Hz): 0.5 s (3H, CH3); 0.73 s,
0.75 s, 0.79 s, 0.82 s (12H, 4CH3); 1.0 1.8 m (16H,
CH2 + CH); 3.5 d (1H, PhCHa, JHH 13.3); 3.8 d (1H,
PhCHb, JHH 13.3); 3.95 d (1H, CHP, JHH 20.8),
4.52 d.t (1H, NH, JHP 26.8, JHH 7), 7.2 7.4 m (10H,
(D2O), , ppm: 7.28 s (5H, C6H5), 4.25 d (1H, PCH,
JHP 17 Hz).
(R)-(Amino)phenylmethylphosphonic acid
(IVb). Hydrochloride. Yield 90%, mp 226 C, [ ]D20
+18.1 (c 0.32, 0.1 N aqueous NaOH). Published data
[7, 8]: (+)-(R)-(amino)phenylmethylphosphonic acid,
2C6H5). 31P NMR spectrum (CDCl3):
24.0 ppm.
20
[ ] + 19 (c 1, 1 N aqueous NaOH). 1H NMR spec-
P
578
Found, %: P 5.31. C35H50NO3P. Calculated, %:
P 5.49.
trum (D2O), , ppm: 7.28 (5H, C6H5), 4.25 d (1H,
PCH, JHP 17 Hz).
Di-(1R,2S,5R)-ment-2-yl [(R)- -(benzylamino)-
benzyl]phosphonate (IIb). Yield 60%, mp 86 87 C,
The NMR spectra were recorded on Varian
(300 MHz) and Jeol (90 MHz) spectrometers in deute-
rated solvents against 85% phosphoric acid. The
optical rotation was measured on a Perkin-Elmer 241
spectropolarimeter . All operations were carried out in
thoroughly dried and purified solvents with protection
from air moisture.
[ ]2D0 57.9 (c 1.0, toluene). H (CDCl3) , ppm,
1
(J, Hz): 0.5 s (CH3), 0.6 0.95 m (18H, 6CH3), 1.1
2.2 m (16H, CH3 + CH); 3.55 d (PhCHa, JHH 13),
3.75 d (PHCHb, JHH 13), 3.98 d (1H, CHP, JHP 20.6),
4.43 m (1H, NH), 7.2 7.4 m (10H, C6H5). 31P NMR
spectrum (CDCl3):
C34H52NO3P. Calculated, %: P 5.59.
21.95 ppm. Found, %: P 5.32.
P
REFERENCES
(S)-(Benzylamino)phenylmethylphosphonic acid
(IIIa) was isolated as hydrochloride and purified by
crystallization from water. Yield 60%, mp 219 C
1. Kolodiazhnyi, O.I., Tetrahedron: Asymmetry, 1998,
vol. 9, no. 7, pp. 1279 1332.
2. Kolodyazhnyi, O.I., Adv. Asymmetric Synthesis, 1998,
vol. 3, pp. 273 357.
3. Kolodyazhnyi, O.I., Grishkun, E.V., Demchuk, O.,
Thoennessen, H., Jones, P., and Schmutzler, R., Tetra-
hedron: Asymmetry, 1998, vol. 9, no. 10, pp. 1645
1648.
(EtOH + H2O), [ ]2D0 26 (c 1, DMSO). H NMR
1
spectrum (DMSO), , ppm: 7.28 m (10H, C6H5),
3.74 4.07 m (3H, NCH + NCH2), 3.48 s (NH+2).
P
7.87 ppm (corresponds to previously described
racemate [9]).
4. Kolodyazhnyi, O.I. and Grishkun, E.V., Tetrahedron:
Asymmetry, 1996, vol. 7, no. 4, pp. 967 970.
5. Kolodyazhnyi, O.I., Demchuk, O., and Gershkovitch, A.,
Tetrahedron: Asymmetry, 1999, vol. 10, no. 9,
pp. 1729 1732.
(R)-(Benzylamino)phenylmethylphosphonic acid
(IIIb). Hydrochloride. Purified by crystallization from
water. mp 219 C (EtOH + H2O), [ ]2D0 +29.9 (c 1,
1
DMSO). H NMR spectrum (DMSO), , ppm: 7.35 m
6. Kolodyazhnyi, O.I., Sheiko, O., and Grishkun, E.V.,
Heteroatom. Chem., 2000, vol. 11, no. 2, pp. 138 143.
7. Kafarski, P., Lejczak, B., and Szewczuk, J., Can. J.
Chem., 1983, vol. 61, no. 11, pp. 2425 2430.
8. Mikolajczyk, M., Lyzwa, P., and Drabowicz, J., Tetra-
hedron: Asymmetry, 1997, vol. 8, no. 24, pp. 3991
3994.
(10H, C6H5), 3.74 4.07 m (3H, NCH + NCH2), 3.48 s
(NH+2).
7.87 ppm.
P
(S)-(Amino)phenylmethylphosphonic acid (IVa).
Hydrochloride. Yield 90%, mp 226 C, [ ]2D0 20
(c 0.32, 0.1 N aqueous NaOH). Published data [7, 8]:
20
( )-(S)-(amino)phenylmethylphosphonic acid, [ ]
578
1
129 (c 1, 1 N aqueous NaOH). H NMR spectrum
9. Tyka, A., Tetrahedron Lett., 1970, no. 5, pp. 677 680.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 7 2001