Stereospecific halogenation of P(O)-H bonds with copper(II) chloride affording optically active Z1Z2P(O)Cl

Article abstract of DOI:10.1021/jo101540d

A general and efficient method for the preparation of optically active Z₁Z₂P(O)Cl from the easily prepared optically active H-phosphinates and H-phosphine oxides was reported. H-Phosphinates and H-phosphine oxides react stereospecifi

Full text of DOI:10.1021/jo101540d

pubs.acs.org/joc
auxiliaries for asymmetric synthesis.3 However, methods
Stereospecific Halogenation of P(O)-H Bonds with
Copper(II) Chloride Affording Optically Active
Z1Z2P(O)Cl
for their preparation are rather limited.4
The highly reactive organophosphorus chlorides Z1Z2P(O)
Cl easily couple with a variety of nucleophiles (Nu) (eq 1).5
They are among the most frequently used starting chemicals
for the preparation of organophosphorus derivatives.
Yongbo Zhou,† Gang Wang,† Yuta Saga,‡ Ruwei Shen,†
Midori Goto,† Yufen Zhao,§ and Li-Biao Han*,†
Z1Z2PðOÞCl Nucleophiles Z Z PðOÞNu
ð1Þ
f
1
2
†National Institute of Advanced Industrial Science and
Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan,
‡Katayama Chemical Industries Co., Ltd., Amagasaki-City,
Hyogo 660-0892, Japan, and §Department of Chemistry and
Key Laboratory for Chemical Biology of Fujian Province,
Xiamen University, Xiamen 361005, China
We assumed that if an optically active Z1Z2P(O)Cl could be
easily prepared and if Z1Z2P(O)Cl could react with a nucleo-
phile stereospecifically, a variety of optically active organo-
phosphorus acid derivatives Z1Z2P(O)Nu would be readily
prepared (eq 2). However, a literature search showed that
although a racemic Z1Z2P(O)Cl was readily available,5a the
preparation of an optically active Z1Z2P(O)Cl was rather
difficult.6 For example, optically active t-BuPhP(O)Br and t-
BuPhP(S)Cl were obtained from the reactions of optically
active t-BuPhP(O)H with N-bromosuccinimide (NBS) and N-
chlorosuccinimide (NCS), respectively,6a whereas t-BuPhP(O)
Cl was obtained from the reaction of an optically active t-
BuPhP(O)H with CH3S(O)Cl (ca. 50% ee),6b NCS,6c or CCl4
and Et3N.6d t-Bu(MeO)P(O)Cl (ca. 66% ee) was obtained via
a similar reaction.6e Recently, an optically active t-BuPhP(Se)
Cl was prepared via the reaction of diastereomerically pure
phosphinoselenoic acid salt with oxalyl chloride.6f,g
libiao-han@aist.go.jp
Received August 5, 2010
A general and efficient method for the preparation of
optically active Z1Z2P(O)Cl from the easily prepared
optically active H-phosphinates and H-phosphine oxides
was reported. H-Phosphinates and H-phosphine oxides
react stereospecifically with CuCl2 to produce the corre-
sponding optically active Z1Z2P(O)Cl with retention of
configuration at the phosphorus center. Optically active
Z1Z2P(O)Cl reacts easily with a variety of nucleophiles to
produce other chiral organophosphorus acid derivatives
with inversion of configuration at phosphorus.
Herein we disclose our studies aiming at developing a
general way for the preparation of these optically active
Z1Z2P(O)Cl 2 and its conversion to other optically active
phosphorus compounds 3 via stereospecific nucleophilic
substitution reactions (eq 2).
Optically active organophosphorus acid derivatives
Z1Z2P(O)Nu1 are important compounds that not only show
a diverse biological activities such as antibacterial, antipsor-
iatic, and anti-HIV effect2 but also are important chiral
Our strategy for the preparation of 2 is to find an efficient
way for the stereospecific halogenation of the relatively easily
accessible secondary phosphine oxides and H-phosphinates7
under mild reaction conditions. Along this line, a few known
halogenation methods of P(O)-H racemates were tested.5a
First, since phosphorochloridates (RO)2P(O)Cl were prepared
(1) (a) Imamoto, T. In Handbook of Organophosphorus Chemistry; Engel,
R., Ed.; Marcel Dekker: New York, 1992; Chapter 1. (b) Quin, L. D. A Guide
to Organophosphorus Chemistry; Wiley-Interscience: New York, 2000; Chap-
ter 9. (c) Sasaki, M. In Chirality in Agrochemicals; Kurihara, N., Miyamoto,
J., Eds.; Wiley & Sons: Chichester, U.K., 1998; p 85.
(2) (a) Kukhar, V. P.; Hudson, H. R. Aminophosphonic and Aminophos-
phinic Acids: Chemistry and Biological Activity; Wiley & Sons: Chichester,
U.K., 2000. (b) Sawa, M.; Tsukamoto, T.; Kiyoi, T.; Kurokawa, K.;
Nakajima, F.; Nakada, Y.; Yokota, K.; Inoue, Y.; Kondo, H.; Yoshino,
K. J. Med. Chem. 2002, 45, 930. (c) Camp, N. P.; Perry, D. A.; Kinchington,
D.; Hawkins, P. C. D.; Hitchcock, P. B.; Gani, D. Bioorg. Med. Chem. 1995,
3, 297.
(4) (a) Koizumi, T.; Yanada, R.; Takagi, H.; Hirai, H.; Yoshii, E.
Tetrahedron lett. 1981, 22, 477. (b) Hall, C. R.; Inch, T. D.; Peacock, G.;
Pottage, C.; Williams, N. E. J. Chem. Soc., Perkin Trans. 1 1984, 669. (c)
Haynes, R. K.; Au-Yeung, T. L.; Chan, W. K.; Lam, W. L.; Li, Z. Y.; Yeung,
L. L.; Chan, A. S. C.; Li, P.; Koen, M.; Mitchell, C. R.; Vonwiller, S. C. Eur.
J. Org. Chem. 2000, 3205. (d) Grabulosa, A.; Granell, J.; Muller, G. Coord.
Chem. Rev. 2007, 251, 25. (e) Bergin, E.; O’Connor, C. T.; Robinson, S. B.;
McGarrigle, E. M.; O’Mahony, C. P.; Gilheany, D. G. J. Am. Chem. Soc.
2007, 129, 9566.
(5) (a) Kosolapoff, G. M.; Maier, L. In Organic Phosphorus Compounds;
Wiley-Interscience: New York, 1972; Vol. 4, Chapter 9. (b) Oliana, M.; King,
F.; Horton, P. N.; Hursthouse, M. B.; Hii, K. K. J. Org. Chem. 2006, 71,
2472. (c) Li, Y. C.; Aubert, S. D.; Maes, E. G.; Raushel, F. M. J. Am. Chem.
Soc. 2004, 126, 8888. (d) Clive, D. L. J.; Kang, S. Z. J. Org. Chem. 2001, 66,
6083. (e) Malachowski, W. P.; Coward, J. K. J. Org. Chem. 1994, 59, 7625.
ꢀ
(3) (a) Darcel, C.; Uziel, J.; Juge, S. In Phosphorous Ligands in Asym-
metric Catalysis; Borner, A., Ed.; Wiley-VCH: Weinheim, 2008; Vol. 3, pp
€
1211-1233. (b) Maj, A. M.; Pietrusiewicz, K. M.; Suisse, I.; Agbossou, F.;
Mortreux, A. Tetrahedron: Asymmetry 1999, 10, 831. (c) Legrand, O.;
Brunel, J. M.; Buono, G. Tetrahedron lett. 1998, 39, 9419. (d) Gamble,
M. P.; Smith, A. R. C.; Wills, M. J. Org. Chem. 1998, 63, 6068. (e) Brown,
J. M.; Carey, J. V.; Russel, M. J. H. Tetrahedron 1990, 46, 4877. (f) Brunel,
J. M.; Legrand, O.; Buono, G. Eur. J. Org. Chem. 2000, 3313. (g) Vinci, D.;
Mateus, N.; Wu, X.; Hancock, F.; Steiner, A.; Xiao, J. Org. Lett. 2006, 8, 216.
(h) Matsukawa, S.; Sugama, H.; Imamoto, T. Tetrahedron Lett. 2000, 41,
6461.
7924 J. Org. Chem. 2010, 75, 7924–7927
Published on Web 10/29/2010
DOI: 10.1021/jo101540d
r
2010 American Chemical Society

Zhou et al.
JOCNote
by reactions of (RO)2P(O)H with CCl4 in the presence of a
base (Atherton-Todd reaction),8 we investigated the chlori-
nation of phosphinate (RP)-1a under the Atherton-Todd
reaction conditions hoping that optically active phosphonic
chloride 2a could be obtained selectively. However, disap-
pointedly, compound (RP)-1a only sluggishly reacted with
CCl4 to yield the corresponding phosphonic chloride 2a as a
mixture of diastereomers (eq 3). Therefore, it was concluded
that this reaction could not be applied to the preparation of
the optically active Z1Z2P(O)Cl 2.
TABLE 1. Chlorination of (i-PrO)2P(O)H with CuCl2 at Room
Temperature
solvent 5 mL
ði-PrOÞ2PðOÞH þ CuCl2
ði-PrOÞ PðOÞCl
f
2
25 °C
2 mmol
1 mmol
entry
solvent
time (h)
GC yield (%)
1
2
3
4
5
6
7
acetone
MeCN
DMF
THF
Et2O
0.5
0.5
0.5
0.5
1
quantitative
quantitative
quantitative
quantitative
73
CH2Cl2
CHCl3
4
4
32
43
CCl4, NEt3
ðRPÞ-1a
ðð - ÞMenOÞPhPðOÞCl
f
room temperature,30 h
2a
ð3Þ
ca: 50% conversion of 1a
diastereomeric ratio of 2a ¼ 70=30
showing that this chlorination reaction took place highly
stereospecifically (vide infra). Similar stereospecific chlorina-
tion also took place efficiently with another optically active
phosphinate (RP)-1b and an secondary phosphine oxide (SP)-
1c to quantitatively produce the corresponding optically
active P(O)Cl compounds 2b and 2c, respectively.
We then turned our attention to another method for the
chlorination of (RO)2P(O)H: the chlorination of (RO)2P(O)H
with CuCl2 described by Smith in 1962.9 Smith reported that
(RO)2P(O)H could be converted to (RO)2P(O)Cl by CuCl2 on
heating at 100 °C in CCl4 (eq 4). Because of the easy operation
and handlingof thechemicals, thismethodishighlyattractive.
However, it was realized that the harsh conditions used would
not besuitablefor thepreparation of opticallyactive2 because
the starting optically active compound H-P(O) 1 as well as the
products 2 might be racemized under such harsh conditions.7
stereospecific chlorination
1a- c
2a- c
ð5Þ
f
quantitative
CuCl2, THF, 0 - 25 °C, <20 min
As to the stereochemistry, crystals suitable for X-ray
analysis were obtained by careful recrystallization of 2c from
hexane, which led to the successful determination of the
absolute configuration at phosphorus to be RP, indicating
that the above chlorination reaction took place via retention
of configuration at phosphorus (Figure 1).
ðROÞ2PðOÞH þ CuCl2
ðROÞ PðOÞCl ð4Þ
f
2
CCl4, 100 °C
We reinvestigated this chlorination reaction and found
that it was highly affected by the solvent used (Table 1).
Thus, although the reaction slowly proceeded in CH2Cl2 or
CHCl3 at room temperature, in solvents such as THF,
MeCN, acetone, and DMF, it completes rapidly to give a
quantitative yield of (i-PrO)2P(O)Cl.
Encouraged by the above results, the chlorination of
(RP)-(L)-menthyl phenylphosphinate (RP)-1a was studied.
Thus, a solution of (RP)-1a (1 mmol in 4 mL of THF) was
added to a solution of CuCl2 (2.1 mmol in 4 mL THF) at
0 °C. The mixture was stirred at room temperature for 10 min.
GC analysis showed the complete consumption of 1a. The
volatiles were removed under a reduced pressure, and the
residues were extracted with hexane (10 mL). Solvent was
removed toleave2aina quantitativeyield (eq5). In 31P NMR,
only one diastereomer of the product could be detected,
FIGURE 1. Single-crystal X-ray structure of compound (RP)-2c.
To our surprise, although-moisture sensitive, these opti-
cally active compounds 2 are rather stable toward racemiza-
tion. In hexane or CHCl3 no racemization took place at
room temperature for 1 week. Compound 2a in benzene is
stable even at 70 °C for 5 days.
As expected, these optically active P(O)Cl compounds are
versatile starting materials for the preparation of a variety of
optically active phosphorus compounds by a stereospecific
replacement of the chlorine atom with a nucleophile. Thus,
(SP)-2a reacted stereospecifically (with inversion of the con-
figuration at phosphorus) with MeMgCl, i-PrMgCl,
PhCH2MgCl, CH2CHCH2MgCl, and TMSCH2MgCl to
give the corresponding optically active phosphinates in high
yields (Table 2, entries 1-5). The stereochemistry at phos-
phorus of the product ((-)MenO)PhMeP(O) (Table 2,
entry 1) was determined to be SP by comparing its optical
rotation with that of the literature,10 showing the substitution
(6) (a) Au-Yeung, T. L.; Chan, K. Y.; Chan, W. K.; Haynes, R. K.;
Williams, I. D.; Yeung, L. L. Tetrahedron Lett. 2001, 42, 453. (b) Drabowicz,
ꢀ
J. Heteroatom. Chem. 2002, 13, 437. (c) Michalski, J.; Skrzypczynski, Z.
J. Chem. Soc., Chem. Commun. 1977, 66. (d) Skrzypczynski, Z.; Michalski, J.
J. Org. Chem. 1988, 53, 4549. (e) Krawiecka, B.; Wojna-Tadeusiak, E.
J. Chem. Soc., Perkin Trans. 1 1991, 229. (f) Kimura, T.; Murai, T. Chem.
Commun. 2005, 4077. (g) Murai, T.; Kimura, T. Curr. Org. Chem. 2006, 10,
1963. (h) Perlikowska, W.; Gouygou, M.; Daran, J. C.; Balavoine, G.;
Mikolajczyk, M. Tetrahedron Lett. 2001, 42, 7841. (i) Corriu, R. J. P.;
Lanneau, G. F.; Leclercq, D. Tetrahedron 1980, 36, 1617.
(7) (a) Xu, Q.; Zhao, C. Q.; Han, L. B. J. Am. Chem. Soc. 2008, 130,
12648. (b) Wang, G.; Shen, R. W.; Xu, Q.; Goto, M.; Zhao, Y. F.; Han, L. B.
J. Org. Chem. 2010, 75, 3890.
(8) (a) Atherton, F.; Openshaw, A.; Todd, A. J. Chem. Soc. 1945, 660. (b)
Atherton, F.; Todd, A. J. Chem. Soc. 1947, 674. (c) For an early observation
on the reaction of (R)-(-)-isopropyl methylphosphinate (4.6% optically
pure) under Todd reaction conditions, see: Reiff, L. P.; Aaron, H. S.
J. Am. Chem. Soc. 1970, 92, 5275.
(9) (a) Smith, T. D. J. Chem. Soc. 1962, 1122. (b) Okamoto, Y.; Kusano,
T.; Takamuku, S. Bull. Chem. Soc. Jpn. 1988, 61, 3359.
J. Org. Chem. Vol. 75, No. 22, 2010 7925

Zhou et al.
JOCNote
TABLE 2. Stereospecific Substitution Reaction of Optically Active
Z1Z2P(O)Cl 2 with C-, O-, S-, and N-Nucleophiles
configurations around phosphorus were easily determined by
comparing with authentic samples.7b The above substitution
reactions also proceeded smoothly with (SP)-2b and (RP)-2c.
To the best of our knowledge, there were no precedents of
preparation of optically active organophosphorus acid deri-
vatives by the stereospecific nucleophilic substitution of opti-
cally active P(O)Cl compounds.6
The stereospecific features of the halogenation of 1 by
CuCl2 forming 2 and the substitution reactions of 2 with
nucleophiles forming 3 are confirmed by the following
experiments using diastereomeric mixtures of 1a and 2a as
substrates, respectively. Thus, reaction of 1a (RP/SP = 64/
36) with CuCl2 produced a diastereometric mixture of 2a
with the same ratio of SP/RP=64/36. Similarly, the substitu-
tion reaction of a diastereomeric mixture of 2a (SP/RP = 64/
36) with MeMgCl gave a diastereometric mixture of 3a (SP/
RP=64/36)10c with inversion of configuration at the phos-
phorus atom.
In summary, we have demonstrated that optically pure
phosphorus chlorides Z1Z2P(O)Cl can be simply prepared
via a stereospecific (retention of configuration) halogena-
tion of the corresponding P(O)H compounds with CuCl2
under mild conditions. These compounds are versatile
starting materials for the preparation of other optically
pure phosphorus acid derivatives, i.e., Z1Z2P(O)Cl reacts
with C-, O-, S-, and N-nucleophiles to produce the corre-
sponding optically active phosphorus compounds via
stereospecific replacement of the chlorine atom (inversion of
configuration).
Experimental Section
Typical Procedure for the Synthesis of 2. To a solution of
CuCl2 (10.5 mmol in 10 mL THF) was added (RP)-1b (5 mmol in
10 mL THF) at 0 °C. The cooling bath was removed, and the
mixture was stirred at room temperature for 10 min. The
volatiles were removed under vacuum. The residue was ex-
tracted with 30 mL of hexane and filtered. After evaporating
the solvent, the desired product (SP)-2b was obtained as a white
solid in quantitative yield. Mp: 64-65 °C; [R]25 = -93.9
D
1
(CHCl3, c 0.986). H NMR (400 MHz, CDCl3): δ 7.36-7.28
(m, 5H), 4.42-4.33 (m, 1H), 3.60-3.45 (m, 2 H), 2.08 (d, J=12.0
Hz, 1H), 1.93-1.88 (m,1H), 1.68-1.62 (m, 2H), 1.42-1.25 (m,
2H), 1.11-0.94 (m, 2H), 0.88-0.78 (m, 7H), 0.74 (d, J=6.8 Hz,
3H). 13C NMR (100 MHz, CDCl3): δ 130.2 (d, JP-C=7.6 Hz),
129.8 (d, JP-C=11.4 Hz), 128.6 (d, JP-C=3.9 Hz), 127.6 (d, JP-C
=
4.7 Hz), 80.9 (d, JP-C = 9.5 Hz), 48.3 (d, JP-C = 6.7 Hz), 42.8,
42.0 (d, JP-C=121.0 Hz), 33.9, 31.6, 25.5, 22.8, 21.8, 21.0, 15.7.
31P NMR (162 MHz, CDCl3): δ 37.8. Anal. Calcd for
C17H26ClO2P: C, 62.10; H, 7.97. Found: C, 62.29; H, 8.08.
Typical Procedure for the Stereospecific Substitution Reaction
of 2. A solution of methylmagnesium chloride (1.1 mmol in 2 mL
THF) was added to a solution of (SP)-2a (1.0 mmol in 3 mL of
THF) at -78 °C and stirred for 2 h, and then the reaction
mixture was slowly warmed to -40 °C. The reaction mixture
was quenched with saturated NH4Cl solution, and the product
was extracted with CHCl3, dried over MgSO4, and concentrated
under vacuum to give NMR spectroscopically pure prod-
uct (SP)-((-)MenO)PhMeP(O) in 98% yield.10 White solid.
aIsolated yield. bReaction conditions: 2 (1 mmol), nucleophile (1.1
mmol) in dry THF (5 mL), -78 °C. cReaction conditions: 2 (1 mmol),
nucleophile (2 mmol), Et3N (2 mmol) in dry THF (5 mL), 0 °C.
1
took place at phosphorus via inversion of configuration.
(SP)-2a also reacted efficiently with other nucleophiles
such as MeOH, i-PrOH, PhOH, PhSH, n-BuNH2, and
H2NCH2CH2NH2 to give the corresponding optically active
phosphorus acid derivatives highly selectively in high yields.
These compounds are known compounds, and the absolute
Mp: 80-81 °C; [R]30D = -92.6 (benzene, c 0.760). H NMR
(500 MHz, CDCl3): δ 7.82-7.78 (m, 2H), 7.54-7.51 (m, 1H),
(10) (a) Nudelman, A.; Cram, D. J. J. Org. Chem. 1971, 36, 335. (b)
Korpiun, O.; Lewis, R. A.; Chickos, J.; Mislow, K. J. Am. Chem. Soc. 1968,
90, 4842. (c) Dabkowski, W.; Ozarek, A.; Olejniczak, S.; Cypryk, M.;
Chojnowski, J.; Michalski, J. Chem.;Eur. J. 2009, 15, 1747.
7926 J. Org. Chem. Vol. 75, No. 22, 2010

Zhou et al.
JOCNote
7.47-7.45 (m, 2H), 3.97-3.93 (m, 1H), 2.37 (d, J=12.0 Hz, 1H),
1.93-1.87 (m, 1H), 1.70 (d, J=15.0 Hz, 3H), 1.62-1.57 (m, 2H),
1.44-1.37 (m, 1H), 1.32-1.19 (m, 2H), 0.90 (d, J=6.0 Hz, 3H),
0.88-0.83 (m, 2H), 0.81 (d, J = 6.5 Hz, 3H), 0.31 (d, J = 7.0 Hz,
3H). 13C NMR (125 MHz, CDCl3): δ 133.4 (d, JP-C=128.8 Hz),
34.1, 31.5, 25.4, 22.7, 21.9, 21.0, 16.5 (d, JP-C=102.0 Hz), 15.2.
31P NMR (202 MHz, CDCl3): δ 40.6.
Supporting Information Available: General experimental
procedures, spectroscopic data for compounds 2 and 3, and
X-ray data for compound (RP)-2c in CIF format. This material
is available free of charge via the Internet at http://pubs.acs.org.
132.0 (d, JP-C=3.1 Hz), 131.1 (d, JP-C= 10.3 Hz), 128.4 (d, JP-C=
12.3 Hz), 76.8 (d, JP-C = 7.3 Hz), 48.8 (d, JP-C=6.3 Hz), 43.8,
J. Org. Chem. Vol. 75, No. 22, 2010 7927