(1R,2S,5R)-menthyl phosphinate and its properties

Full text of DOI:10.1007/s11176-005-0290-2

Russian Journal of General Chemistry, Vol. 75, No. 4, 2005, pp. 656 657. Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 4, 2005,
pp. 694 695.
Original Russian Text Copyright
2005 by Kolodyazhnyi.
LETTERS
TO THE EDITOR
(1R,2S,5R)-Menthyl Phosphinate and Its Properties
O. I. Kolodyazhnyi
Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, Kiev, Ukraine
Received September 3, 2004
Proceeding with our research into chiral esters of
phosphorous acid we synthesized (1R,2S,5R)-menthyl
phosphinate (I) [1 3]. Compound I was prepared by
the reaction of anhydrous hypophosphorous acid with
(1R,2S,5R)-menthol in the presence of trimethyl
orthoformate in THF. The reaction occurred smoothly
and completely to give pure (1R,2S,5R)-menthyl
phosphinate (I) in high yield.
stable compounds [4, 5], compound I is relatively
stable and can be purified by high-vacuum distillation.
Its stability is probably explained by the steric effect
of the menthyl group. The structure of the product
1
was confirmed by its H and 31P NMR spectra and
chemical transformations. The 31P NMR spectrum
contains a triplet at 11 ppm (1JPH 567 Hz) that col-
1
lapses to a singlet in the 31P {1H} spectrum. The H
NMR spectrum contains a doublet of doublets at 7.16
and 7.17 ppm with the same 1JPH constant, correspond-
ing to magnetically nonequivalent PH2 protons. Com-
pound I enters the Heck reaction with iodobenzene in
the presence of a palladium complex to form in high
yield diastereomerically enriched (SP)-( )-menthyl
phenylphosphonite (II) that was purified by column
chromatography on silica gel.
O
P
H
OH
O
CH(OMe)3
H
+ HOP(O)H2
I
Unlike known hypophosphites that are quite un-
O
H
O
NHPr-i
O
P
O
P
Ph
PhI
CCl4/i-PrNH2
R
I
Pd(Ph3P)2Cl2,
Et3N
SP-II
IIIa, IIIb
R = H (a), NHPr-i (b).
The Todd Atherton reaction of compound I with
carbon tetrachloride and isopropylamine involves
consecutive replacement of the hydrogen atoms at
phosphorus by amino groups to produceinitially
monoamide IIIa (detected by NMR spectroscopy) and
then diamide IIIb (isolated as crystals). Other trans-
formations of (1R,2S,5R)-menthyl phosphinate (I) will
be reported in further publications.
kept for 3 h at 20°C, and volatile compounds were
removed in vacuo. The residue was a spectroscopical-
ly pure compound I which can be distilled in a high
vacuum if necessary. Yield 90% (without distilla-
1
tion), bp 85 90°C (0.01 mm Hg). H NMR spectrum
3
(C6D6), , ppm (J, Hz): 0.74 d [3H, CH3C, JHH 8];
0.86, d (3H, (CH3)2Ca, 3JHH 7); 0.87, d (3H, (CH3)2Cb,
3JHH 7); 0.8 2.0 m (9H, CH2 + CH); 4.1 m (ABX
1
system, 1H, CHOP); 7.16 d (1H, PH, JHP 558);
1
(1R,2S,5R)-Menthyl phosphinate (I). Anhydrous
hypophosphorus acid, 0.05 mol, in THF was treated
consecutively with 0.06 mol of trimethyl orthoformate
and 0.06 mol of (1R,2S,5R)-menthol. The mixture was
7.17 d (1H, PH, JHP 559). 31P NMR spectrum
3
(CDCl3), , ppm (J, Hz):
10.5, d.t (1JPH 557, JHH
P
10). Found, %: P 15.06. C10H21O2P. Calculated, %:
P 15.16.
1070-3632/05/7504-0656 2005 Pleiades Publishing, Inc.

(1R,2S,5R)-MENTHYL PHOSPHINATE AND ITS PROPERTIES
657
(1R,2S,5R)-Menthyl (S)-phenylphosphonate (II).
Bis(triphenylphosphine)palladium dichloride, 0.05 g,
was added to a solution of 0.003 mol of menthyl
phosphinate I, 0.003 mol of iodobenzene, and
0.004 mol of triethylamine in 4 ml of acetonitrile. The
mixture was heated for 2 3 h at the bath temperature
100°C. The precipitate that formed was filtered off,
the solvent was evaporated, and the residue was sub-
jected to column chromatography on silica gel, eluent
hexane ethyl acetate, 3:1. Compound II was purified
additionally by low-temperature crystallization from
hexane. Rf 3.2, Yield 60%, [ ]2D0 21 (c 4, benzene)
[6]. 1H NMR spectrum (CDCl3), , ppm (J, Hz):
was then separated, the solvent was evaporated, and
the residue was recrystallized from hexane to obtain
compound IIIb, yield 70%, mp 128 129°C. H NMR
1
spectrum (CDCl3), , ppm (J, Hz): 0.80 d [3H,
3
3
(CH3C, JHH 7]; 0.87 d [3H, (CH3)2Ca, JHH 7];
0.89 d [3H, (CH3)2Cb, JHH 7]; 1.0 2.1 m (9H,
3
CH + CH2); 2.0 m (2H, NH); 3.35 m (2H, CHN);
4.15 m (1H, CHOP). 31P NMR spectrum (CDCl3),
P
11.9 ppm. Found, %: N 8.95; P 9.99. C16H35N2O2P.
Calculated, %: N 8.80; P 9.73.
The NMR spectra were measured on a Varian-300
instrument, internal references TMS (1H) and
85% H3PO4 in D2O (31P).
3
0.60 d [3H, (CH3)2Ca, JHH 8]; 0.61 d [3H, (CH3)2Cb,
3
3JHH 8]; 0.8 d [3H, CH3, JHH 7); 1.1 2.1 m (9H,
REFERENCES
1
CH + CH2); 3.5 m (1H, CHOP); 7.6 d (1H, PH, JHP
556); 7.4 m; 7.6 m (5H, C6H5). 31P NMR spectrum
1. Kolodiazhnyi, O.I., Tetrahedron: Asymmetry, 1998,
1
3
(CDCl3), , ppm (J, Hz):
20.5 d.d, JHP 557, JHH
P
vol. 9, no. 8, p. 1279.
13.0. Found, %: P 11.16. C16H25O2P. Calculated, %:
P 11.05.
2. Kolodiazhnyi, O.I., Grishkun, E.V., and Sheiko, S.,
Heteroatom. Chem., 2000, vol. 11, no. 2, p. 138.
(1R,2S,5R)-Menthyl N,N -diisopropylphosphoro-
diamidate (IIIb). Carbon tetrachloride, 0.0075 mol,
and 0.015 mol of isopropylamine were added to a
cooled and stirred solution of 0.01 mol menthyl phos-
phinate I in ether. The 31P NMR spectrum of the re-
action mixture was showed two doublets of doublets
corresponding to diastereomeric menthyl isopropyl-
phosphonamidates IIIa in a 2:1 ratio, P, ppm (J, Hz):
3. Kolodiazhnyi, O.I., Grishkun, E.V., Sheiko, S.,
Demchuk, O., Thoennessen, H., Jones, P.G., and
Schmutzler, R.., Tetrahedron: Asymmetry, 1998, vol. 9,
no. 9, p. 1645.
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Khim., 1980, vol. 49, no. 1, p. 92.
5. Gallagher, M.J., Ranasinghe, M.G., and Jenkins, I.D.,
Phosphorus, Sulfur Silicon, 1996, vol. 115, no. 1,
p. 255.
3
11.2 d.d (1JHP 610, JHH 13.5), 8.9 d.d (1JHP 615,
3JHH 13.0). Additional 0.01 mol of carbon tetrachlo-
ride and 0.02 mol of isopropylamine were added to
the reaction mixture, isopropylamine hydrochloride
6. DeBruin, K.E. and Mislow, K., J. Am. Chem. Soc.,
1969, vol. 91, no. 26, p. 7393.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 4 2005