P-chiral phosphinoselenoic chlorides and phosphinochalcogenoselenoic acid esters: Synthesis, characterisation, and conformational studies

Article abstract of DOI:10.1021/jo0484979

(Chemical Equation Presented) P-Chiral alkyl or aryl phenylphosphinoselenoic chlorides were obtained by reacting PhPCl₂ with Grignard reagents and elemental selenium. P-Chiral dialkyl chlorides were also obtained by treating PCl₃ with two different Grignard reagents and elemental selenium. The structure of the chloride was determined by X-ray molecular structure analysis. P-Chiral phosphinochalcogenoselenoic acid esters bearing a P=Se double bond were synthesized by treating the chlorides with alkali metal alkoxide and chalcogenolates, whereas those bearing a P-Se single bond were obtained by sequential treatment of the chlorides with sodium hydroxide, sulfide or selenide, and alkyl iodides. X-ray molecular structure analyses of esters showed that they adopted gauche conformations. The computational results supported the observed conformational preference. Natural bond orbital analyses of the model compounds showed that two types of nonbonding orbital interactions, n_E′ → σ*_P=E and n_E → σ*_P-E′, are important in these compounds. Linear correlations were observed between the experimental ⁷⁷Se NMR chemical shifts or the coupling constants of P-Se bonds in the esters and the calculated P-Se bond lengths of the model compounds.

Full text of DOI:10.1021/jo0484979

P-Chiral Phosphinoselenoic Chlorides and
Phosphinochalcogenoselenoic Acid Esters: Synthesis,
Characterization, and Conformational Studies
Tsutomu Kimura and Toshiaki Murai*
Department of Chemistry, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan
mtoshi@cc.gifu-u.ac.jp
Received August 26, 2004
P-Chiral alkyl or aryl phenylphosphinoselenoic chlorides were obtained by reacting PhPCl2 with
Grignard reagents and elemental selenium. P-Chiral dialkyl chlorides were also obtained by treating
PCl3 with two different Grignard reagents and elemental selenium. The structure of the chloride
was determined by X-ray molecular structure analysis. P-Chiral phosphinochalcogenoselenoic acid
esters bearing a PdSe double bond were synthesized by treating the chlorides with alkali metal
alkoxide and chalcogenolates, whereas those bearing a P-Se single bond were obtained by sequential
treatment of the chlorides with sodium hydroxide, sulfide or selenide, and alkyl iodides. X-ray
molecular structure analyses of esters showed that they adopted gauche conformations. The
computational results supported the observed conformational preference. Natural bond orbital
analyses of the model compounds showed that two types of nonbonding orbital interactions, nE′
f
σ*P)E and nE f σ*P-E′, are important in these compounds. Linear correlations were observed between
the experimental 77Se NMR chemical shifts or the coupling constants of P-Se bonds in the esters
and the calculated P-Se bond lengths of the model compounds.
Introduction
Studies on P-chiral phosphinic-,1 phosphinothioic-,2 and
phosphinodithioic acid derivatives3 I and II have made
important contributions to the field of synthetic chem-
istry. In contrast, much less attention has been paid to
selenium-containing P-chiral phosphinic acid derivatives,
that is, phosphinochalcogenoselenoic acid derivatives III
and IV (Figure 1).
This is mainly due to the lack of the appropriate
starting materials leading to these compounds. Never-
theless, compounds III are of great interest because the
PdSe group exhibits lower polarity and higher affinity
toward soft metals than the PdO group. Consequently,
derivatives III (E ) O) have been reported,4 and their
reactions such as isomerization of allyl esters5 have been
disclosed. However, there are scarce examples of the
FIGURE 1. P-Chiral phosphinochalcogenoselenoic acid de-
rivatives.
synthesis of P-chiral derivatives III and IV (E ) S, Se).
Very recently, we reported the synthesis and character-
ization of P-chiral phosphinoselenoic chlorides and their
conversion to optically active P-chiral phosphinoselenoic
amides.6 We report here the synthesis and spectroscopic,
structural, and theoretical studies on a series of P-chiral
phosphinochalcogenoselenoic acid esters III and IV along
with the detailed synthesis and structure of P-chiral
phosphinoselenoic chlorides.
(1) (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)
Horner, L.; Schlotthauer, B. Phosphorus Sulfur 1978, 4, 155.
(2) Krawiecka, B.; Michalski, J.; Wojna-Tadeusiak, E. J. Org. Chem.
1986, 51, 4201.
Results and Discussion
Synthesis of P-Chiral Phosphinoselenoic Chlo-
rides. As we previously reported, P-chiral phosphino-
(3) (a) Kawashima, T.; Kojima, S.; Inamoto, N. Chem. Lett. 1989,
849. (b) Omelanczuk, J.; Mikolajczyk, M. J. Chem. Soc., Chem.
Commun. 1994, 2223.
(5) (a) Nuretdinov, I. A.; Buina, N. A.; Bayandina, E. V.; Loginova,
E. I.; Gainullina, R. G. Zh. Obshch. Khim. 1978, 48, 547. (b) Nuret-
dinov, I. A.; Buina, N. A.; Bayandina, E. V. Zh. Obshch. Khim. 1978,
48, 1073.
(4) (a) Bayandina, E. V.; Nuretdinov, I. A. Zh. Obshch. Khim. 1976,
46, 288. (b) Bayandina, E. V.; Nuretdinov, I. A.; Nurmukhamedova,
L. V. Zh. Obshch. Khim. 1978, 48, 2673.
(6) Kimura, T.; Murai, T. Chem. Lett. 2004, 878.
10.1021/jo0484979 CCC: $30.25 © 2005 American Chemical Society
Published on Web 01/06/2005
952
J. Org. Chem. 2005, 70, 952-959

Synthesis of P-Chiral Chlorides and Acid Esters
SCHEME 1
TABLE 1. Synthesis of P-Chiral Phosphinoselenoic
Chloridesa
entry
1
R
yield (%)b
1
2
3
4
5
6
7
1a
1b
1c
1d
1e
1f
i-Pr
91
96
82
94
61
72
68
c-Hex
sec-Bu
t-Bu
2-MeOC6H4
4-MeC6H4
4-ClC6H4
FIGURE 2. ORTEP drawing of phosphinoselenoic chloride
1b with thermal ellipsoid plot (50% probability). Hydrogen
atoms are omitted for clarity. Selected bond lengths (Å): P-Se,
2.0812(7); P-Cl, 2.0534(9); P-C1, 1.805(3); P-C2, 1.819(2).
Selected bond angles (°): Se-P-Cl, 112.57(4); Se-P-C1,
115.19(8); Se-P-C2, 116.23(8); Cl-P-C1, 101.97(9); Cl-P-
C2, 102.53(8); C1-P-C2, 106.7(1).
1g
a The reaction was carried out with 10-30 mmol of PhPCl2 and
alkyl (1.0 equiv) or aryl (0.2 equiv) Grignard reagents in the
presence of elemental selenium (1.1 equiv) in THF under Ar.
b Yields of isolated products based on the Grignard reagents.
SCHEME 3
SCHEME 2
TABLE 2. Synthesis of P-Chiral
Phosphinochalcogenoselenoic Acid Esters
selenoic chlorides were synthesized by reacting PhPCl2
with Grignard reagents and elemental selenium (Scheme
1, Table 1).6 As Grignard reagents, secondary and tertiary
alkyl Grignard reagents were used, and alkyl phen-
ylphosphinoselenoic chlorides 1a-d were obtained in
good to high yields (entries 1-4). As for the synthesis of
diaryl derivatives 1e-g, excess PhPCl2 was reacted with
aryl Grignard reagents (entries 5-7). The method for the
synthesis of chlorides bearing two different alkyl groups
on the phosphorus atom was developed further (Scheme
2). The sequential addition of two different Grignard
reagents to a mixture of PCl3 and elemental selenium
successfully gave dialkyl chlorides 1h and 1i. The result-
ing phosphinoselenoic chlorides were air- and moisture-
stable and could easily be handled under air, despite the
fact that phosphinic chlorides were prone to be hydro-
lyzed.
The formation of chlorides 1 was unequivocally dem-
onstrated by X-ray molecular structure analysis (Figure
2). This is the first X-ray molecular structure analysis of
phosphinoselenoic chlorides. The phosphorus atom adopts
a slightly distorted tetrahedral structure. The PdSe
group is located in an equatorial position in the cyclohexyl
ring. The P-Cl bond length (2.053 Å) is close to that of
the sulfur derivative (2.063 Å)7 and slightly longer than
that of the oxygen derivative (2.017 Å).8
entry
1
R
ester
R′
E
R′EM
yield (%)e
1a
2a
3b
4b
5b
6b
7c
8c
9c
1d t-Bu
1b c-Hex
1d t-Bu
1a i-Pr
1d t-Bu
1d t-Bu
1d t-Bu
1d t-Bu
1d t-Bu
2a
2b
3a
3b
3c
3d
4a
4b
4c
Et
O
O
S
S
S
S
EtONa
EtONa
BuSLi
BuSLi
PhSLi
R′′SLid
98
93
95
99
79
93
96
66
99
Et
Bu
Bu
Ph
R′′d
Bu
Se BuSeLi
t-Bu Se t-BuSeLi
Ph Se PhSeLi
a Chloride 1 was treated with EtONa (2 equiv) under reflux in
EtOH for 3 h. b Chloride 1 was treated with R′SLi (1 equiv) in
THF at 0 °C for 1 h. c Chloride 1 was treated with R′SeLi (1 equiv)
in THF at 0 °C for 15 min. d R′′ ) Me3SiCH2CH2. e Yields of
isolated products.
Initially, the synthesis of P-chiral phosphinochalco-
genoselenoic acid esters bearing a PdSe double bond 2-4
was carried out by treating the chlorides 1 with alkali
metal alkoxide and chalcogenolates (Scheme 3, Table 2).
The reaction of the chlorides 1b and 1d with sodium
ethoxide proceeded under reflux in EtOH to give phos-
phinoselenoic acid O-ethyl esters4 2a and 2b in respective
yields of 98 and 93% (entries 1 and 2). Phosphinoselenoic
chlorides 1 were then converted to various phosphinose-
lenothioic acid S-esters9 3a-d by reacting them with
lithium thiolates such as lithium 1-butanethiolate, ben-
zenethiolate, and (2-trimethylsilyl)ethanethiolate (entries
3-6). Furthermore, a similar reaction of chlorides 1 with
lithium selenolates gave phosphinodiselenoic acid alkyl
and aryl esters10 4a-c in moderate to high yields (entries
7-9).
Synthesis of P-Chiral Phosphinochalcogenosele-
noic Acid Esters. Since phosphinoselenoic chlorides 1,
which were key precursors of phosphinoselenoic acid
derivatives, were obtained, the synthesis of five different
types of phosphinochalcogenoselenoic acid esters was
examined by using the chlorides 1 as starting materials.
Next, a variety of P-chiral phosphinochalcogenoselenoic
acid esters bearing a P-Se single bond 8, 9, and 4 were
(7) Boese, R.; Ha¨egele, G.; Ku¨eckelhaus, W.; Seega, J.; Tossing, G.
Chem.-Ztg. 1985, 109, 233.
(8) Kardanov, N. A.; Tkachev, V. V.; Godovikov, N. N.; Kabachnik,
M. I. Izv. Akad. Nauk SSSR, Ser. Khim. 1984, 5, 1052.
(9) Murai, T.; Kimura, T.; Miwa, A.; Kurachi, D.; Kato, S. Chem.
Lett. 2002, 914.
(10) Kuchen, W.; Knop, B. Chem. Ber. 1966, 99, 1663.
J. Org. Chem, Vol. 70, No. 3, 2005 953

Kimura and Murai
TABLE 4. Selected NMR Spectroscopic Data of
SCHEME 4
Phosphinochalcogenoselenoic Acid Alkyl Esters
TABLE 3. Synthesis of P-Chiral
Phosphinochalcogenoselenoic Acid Se-Esters
entry
1
R
ester R′
E
reactants
yield (%)d
1a
2a
3b
4b
5c
1d t-Bu
1b c-Hex
1d t-Bu
1a i-Pr
1d t-Bu
8a
8b
9a
9b
4d
Me
Et
Me
Bu
O
O
S
NaOH/MeI
NaOH/EtI
Na2S/MeI
Na2S/BuI
98
95
90
93
94
S
Me Se Na2Se/MeI
a Chloride 1 was treated with NaOH (10 equiv) in CH3CN at
room temperature for 24 h, and then to the reaction mixture was
added alkyl iodide (2 equiv) at room temperature. b Chloride 1 was
treated with Na2S (5 equiv) in CH3CN at room temperature for 6
h, and then to the reaction mixture was added alkyl iodide (2
equiv) at room temperature. c Chloride 1a was treated with Na2Se
(1.1 equiv) in CH3CN at 0 °C for 4 h, and then to the reaction
mixture was added methyl iodide (2 equiv) at 0 °C. d Yields of
isolated products.
a Measured in CDCl3.
oxygen atom to the selenium atom, the signals 2a, 3a,
and 4d were shifted to lower fields, and those of 8a, 9a,
and 4d were also shifted to lower fields. The coupling
constants between the phosphorus and selenium atoms
of 2a, 3a, and 4d were 764-786 Hz, which belonged to
typical values for coupling constants between PdSe
double bonds. Alternatively, typical coupling constants
of P-Se single bonds (366-391 Hz) were detected for the
esters 8a, 9a, and 4d. In the former case, the coupling
constants decreased in the order 2a [P(Se)O] to 3a
[P(Se)S] and 4d [P(Se)Se]. Similarly, the coupling con-
stants of P-Se single bonds decreased in the order 8a
[P(O)Se] to 9a [P(S)Se] and 4d [P(Se)Se].
X-ray Molecular Structure Analyses of Phosphi-
nochalcogenoselenoic Acid Esters. The molecular
structures of phosphinoselenothioic 3d and phosphino-
diselenoic acid esters 4c were determined by X-ray
molecular structure analyses. ORTEP drawings of the
esters 3d and 4c are shown in Figures 3 and 4. The
torsion angles in 3d (Se-P-S-C3) and 4c (Se1-P-Se2-
C3) are -34.8° and -53.0°, respectively, which indicate
that these molecules preferred a gauche conformation in
the solid state.14 In each case, the substituents on the
chalcogen atoms are located anti to the bulky tert-butyl
group. The phosphorus atoms adopt a slightly distorted
tetrahedral structure, and no significant change in the
P-C bond lengths or the angles around the phosphorus
atom was observed compared to those in phosphinosele-
noic chloride 1b.
synthesized by alkylation of the phosphinochalcogeno-
selenoic acid salts 5-7 (Scheme 4, Table 3). Phosphino-
selenoic acid salts11 5 were successfully generated by
reacting the chlorides 1b and 1d with sodium hydroxide.
Alkylation of the salts 5 with alkyl iodides such as methyl
iodide and butyl iodide proceeded smoothly at the sele-
nium atom to form phosphinoselenoic acid Se-esters11,12
8a and 8b in high yields (entries 1 and 2). When the
chlorides 1 were treated with sodium sulfide, phosphino-
selenothioic acid salts9,10 6 were generated in situ. The
resulting salts 6 were reacted with alkyl iodides to give
phosphinoselenothioic acid Se-esters9,10 9 (entries 3, 4).
In this reaction, the alkyl groups were selectively intro-
duced to the selenium atom of the salts 6. As an
alternative method for the synthesis of diselenoic acid
esters 4, the chloride 1a was reacted with Na2Se, and
the reaction of the resulting phosphinodiselenoic acid
salt13 7 with methyl iodide gave ester 4d in 94% yield
(entry 5). Notably, all of the esters were stable both as a
solid and in solution under air.
Spectroscopic Properties of Phosphinochalco-
genoselenoic Acid Esters. The spectroscopic properties
of selected alkyl esters 2a, 3a, 4d, 8a, and 9a are shown
in Table 4. In the 31P NMR spectra, the signals of the
esters were observed at 90 ( 22 ppm. The signal of
O-ester 2a was observed at a lower field than those of
S-ester 3a and Se-ester 4d by about 23-27 ppm, whereas
the signal of the ester 8a was shifted upfield by about
15-20 ppm compared to those of the corresponding sulfur
9a and selenium derivatives 4d. In the 77Se NMR spectra,
the signals of the selenium atom in the PdSe double bond
of 2a, 3a, and 4d were observed in the range of -350 to
-280 ppm. On the other hand, the signals of the selenium
atom in the P-Se single bond of 8a, 9a, and 4d were
observed in the range of 54-113 ppm. On going from the
Calculation. To elucidate the conformational prefer-
ence of the esters, geometry optimizations and energy
calculations for model compounds 2′-4′, 8′, and 9′ were
performed using the 6-31+G(d) basis set at the B3LYP
level15 with the Gaussian 98 program16 (Scheme 5). In
each case, three conformations, that is, eclipsed, gauche,
and anti conformations, were optimized (Figure 5). The
(11) Kawashima, T.; Iwanaga, H.; Okazaki, R. Heteroat. Chem. 1995,
6, 235.
(12) Krawiecka, B. Heteroat. Chem. 1992, 3, 385.
(13) Davies, R. P.; Martinelli, M. G. Inorg. Chem. 2002, 41, 348.
(14) Lepicard, G.; De Saint-Giniez, D.; Laurent, A.; Rerat, C. Acta
Crystallogr., Sect. B 1969, 25, 617.
(15) Becke’s three parameter hybrid method using the LYP correla-
tion functional: Becke, A. D. J. Chem. Phys. 1993, 98, 5648.
954 J. Org. Chem., Vol. 70, No. 3, 2005

Synthesis of P-Chiral Chlorides and Acid Esters
FIGURE 5. Newman projections of H2P(E)E′CH3 along the
P-E′ Bonds.
SCHEME 5
TABLE 5. Relative Conformational Energies (kcal/mol)
of Model Compounds H2P(E)E′Ch3 [B3LYP/6-31+G(d)]
conformation
2′
3′
4′
8′
9′
FIGURE 3. (a) ORTEP drawing of phosphinoselenothioic acid
S-ester 3d with thermal ellipsoid plot (50% probability). (b)
The view of 3d along the P-S bond. Hydrogen atoms are
omitted for clarity. Selected bond lengths (Å): Se-P,
2.1034(9); P-S, 2.096(1); P-C1, 1.858(3); P-C2, 1.814(3);
S-C3, 1.822(3). Selected bond angles and torsion angle (°):
Se-P-S, 114.47(5); Se-P-C1, 114.3(1); Se-P-C2, 111.9(1);
S-P-C1, 101.8(1); S-P-C2, 107.0(1); C1-P-C2, 106.5(1);
P-S-C3, 102.2(1); Se-P-S-C3, -34.8(1).
anti
eclipsed
gauche
+2.580 +1.744 +0.889 +2.477 +1.813
+1.244 +0.827 +0.427 +0.967 +0.516
0.000
0.000
0.000
0.000
0.000
TABLE 6. NBO Analysis of H2P(E)E′Ch3 at B3LYP/
6-31+G(d) Level (kcal/mol)
2′
3′
4′
8′
9′
n
E′ f σ*P)E
E f σ*P-E′
6.3
19.1
3.5
16.5
2.0
17.5
6.1
27.2
3.0
20.8
n
2′-4′, 8′, and 9′ may be more important than steric
effects.
To obtain further information about the stereoelec-
tronic effects, natural bond orbital (NBO) analyses were
carried out for model compounds 2′-4′, 8′, and 9′, which
adopted gauche conformation. The delocalization energies
are listed in Table 6. The NBO analyses suggested that
two types of nonbonding orbital interactions were im-
portant: (1) interaction between the lone pair of chalco-
gen atoms of P-E′ single bonds and the antibonding
orbital of PdE double bonds (nE′ f σ*P)E) and (2)
interaction between the lone pair of chalcogen atoms of
PdE double bonds and the antibonding orbital of P-E′
single bonds (nE f σ*P-E′). The preference for the gauche
conformation may be due to the former interactions
(nE′ f σ*P)E). The interaction (nE′ f σ*PdSe) in 2′ was
greater than those in 3′ and 4′. Similarly, the energy
difference between the gauche and eclipsed conformations
in 2′ was greater than those in 3′ and 4′. Furthermore,
among 4′, 8′, and 9′, the interaction (nSe f σ*P)E) in 8′
was the greatest. This result is consistent with the
FIGURE 4. (a) ORTEP drawing of phosphinodiselenoic acid
ester 4c with thermal ellipsoid plot (50% probability). (b) The
view of 4c along the P-Se2 bond. Hydrogen atoms are omitted
for clarity. Selected bond length (Å): Se1-P, 2.099(1); Se2-
P, 2.259(1); P-C1, 1.864(4); P-C2, 1.816(4); Se2-C3,
1.922(3). Selected bond angles and torsion angle (°): Se1-P-
Se2, 114.77(5); Se1-P-C1, 114.9(1); Se1-P-C2, 112.6(1);
Se2-P-C1, 100.2(1); Se2-P-C2, 107.4(1); C1-P-C2,
105.8(2); P-Se2-C3, 101.1(1); Se1-P-Se2-C3, -53.0(1).
(16) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Zakrzewski, V. G.; Montgomery, J. A.,
Jr.; Stratmann, R. E.; Burant, J. C.; Dapprich, S.; Millam, J. M.;
Daniels, A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J.;
Barone, V.; Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo,
C.; Clifford, S.; Ochterski, J.; Petersson, G. A.; Ayala, P. Y.; Cui, Q.;
Morokuma, K.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.;
Foresman, J. B.; Cioslowski, J.; Ortiz, J. V.; Stefanov, B. B.; Liu, G.;
Liashenko, A.; Piskorz, P.; Komaromi, I.; Gomperts, R.; Martin, R. L.;
Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.;
Gonzalez, C.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.;
Wong, M. W.; Andres, J. L.; Gonzalez, C.; Head-Gordon, M.; Replogle,
E. S.; Pople, J. A. Gaussian 98, revision A.7; Gaussian, Inc.; Pittsburgh,
PA, 1998.
anti conformations were expected to be more stable than
the others because of steric considerations. However, the
gauche conformations were found to be the most stable
in all cases (Table 5). This result is in good agreement
with X-ray structure analyses of 3d and 4c. Thus, the
stereoelectronic effects around the phosphorus atom in
J. Org. Chem, Vol. 70, No. 3, 2005 955

Kimura and Murai
TABLE 7. B3LYP/6-31+G(d)-Optimized Geometries of
Model Compounds H2P(E)E′Ch3
compound
2′
3′
4′
Se
Se
Bond Length (Å)
8′
9′
E
E′
Se
Se
O
S
O
S
Se
Se
P)E
P-E′
2.092
1.638
2.106
2.138
2.110
1.499
2.258
1.962
2.281
2.287
Angle (deg)
41.4
E-P-E′-C
50.3
33.1
54.5
41.3
shorter P-Se bond length in 8′ (2.258 Å) compared with
those in 4′ (2.287 Å) and 9′ (2.281 Å), as shown in Table
7.
Finally, the relationship between spectroscopic proper-
ties of the esters and optimized parameters of the model
compounds 2′-4′, 8′, and 9′ was observed (Tables 4 and
7). Although no linear correlation was observed between
calculated P-Se bond lengths and 31P NMR chemical
shifts of the esters, P-Se bond lengths of model com-
pounds were linearly correlated with the signals of esters
in the 77Se NMR spectra: δ (77Se) ) 2350 × L (P-Se) -
5255 (R2 ) 0.9980) (Figure 6). Furthermore, a linear
correlation was also observed for the calculated P-Se
bond lengths of model compounds with the coupling
constants between the phosphorus atom and the sele-
nium atom of the esters: JPSe ) -2277 × L (P-Se) +
5558 (R2 ) 0.9955) (Figure 7).
FIGURE 6. Plot of 77Se NMR chemical shifts against calcu-
lated P-Se bond lengths.
In summary, we obtained five different types of P-
chiral phosphinochalcogenoselenoic acid esters from P-
chiral phosphinoselenoic chlorides and appropriate oxy-
gen and chalcogen nucleophiles. The gauche effect caused
by the stereoelectronic effect was observed for the stable
conformations of the esters. Furthermore, linear correla-
tions were observed between the calculated P-Se bond
lengths of model compounds and the 77Se NMR chemical
shifts or the coupling constants of P-Se bonds.
FIGURE 7. Plot of JPSe against calculated P-Se bond lengths.
(d, JSeP ) 841.9 Hz); MS(EI) m/z: 266 (M+); HRMS calcd for
C9H12ClPSe: 265.9530. Found: 265.9537.
Experimental Section
P-Cyclohexyl-P-phenylphosphinoselenoic Chloride
(1b). A colorless solid. mp: 79-81 °C (dec); 1H NMR: δ 1.12-
1.38 (m, 4H), 1.50-1.77 (m, 4H), 1.88-1.92 (m, 1H), 2.13-
2.17 (m, 1H), 2.39-2.49 (m, 1H), 7.47-7.56 (m, 3H), 7.98-
8.03 (m, 2H); 13C NMR: δ 25.4 (d, JCP ) 1.7 Hz), 25.7 (d, JCP
) 7.4 Hz), 25.8 (d, JCP ) 5.6 Hz), 26.0 (d, JCP ) 3.3 Hz), 26.3,
49.4 (d, JCP ) 47.4 Hz), 128.5 (d, JCP ) 13.2 Hz), 131.9 (d, JCP
) 11.2 Hz), 132.1 (d, JCP ) 71.1 Hz), 132.6 (d, JCP ) 3.3 Hz);
31P NMR: δ 95.8 (JPSe ) 840.4 Hz); 77Se NMR: δ -196.5 (d,
JSeP ) 840.4 Hz); MS(EI) m/z: 306 (M+); Anal. Calcd for C12H16-
ClPSe: C, 47.16; H, 5.28. Found: C, 47.33; H, 5.18.
General Procedures. All reactions were carried out under
an argon atmosphere. Na2Se was prepared according to the
literature.17 Silica gel used in column chromatography was
silica gel 60 from a commercial supplier.
General Procedure for the Synthesis of Alkyl Phe-
nylphosphinoselenoic Chlorides 1a-d. A Representative
Procedure for the Synthesis of P-(1-Methylethyl)-P-
phenylphosphinoselenoic Chloride (1a). To a suspension
of elemental selenium (0.695 g, 8.80 mmol) in THF (40 mL)
was added PhPCl2 (1.09 mL, 8.00 mmol) at room temperature
under an Ar atmosphere. To this mixture was added i-PrMgCl
(2.0 mol/L Et2O solution, 4.00 mL, 8.0 mmol) in THF (36 mL)
dropwise over a period of 1 h at 0 °C with vigorous stirring.
After the solvent was removed, toluene (20 mL) was added to
the residue. The mixture was stirred under reflux in toluene
for 1 h, and the insoluble parts were filtered off. After the
solvent was removed, the residue was purified by column
chromatography on silica gel using n-C6H14/CH2Cl2 as eluent
to give 1.927 g (91%) of 1a as a colorless oil. 1H NMR: δ 0.97
(dd, J ) 6.8 Hz, JHP ) 24.2 Hz, 3H), 1.36 (dd, J ) 6.8 Hz, JHP
) 22.9 Hz, 3H), 2.76 (d of heptets, J ) 6.8 Hz, JHP ) 9.8 Hz,
1H), 7.48-7.58 (m, 3H), 7.99-8.06 (m, 2H); 13C NMR: δ 16.5
P-(1-Methylpropyl)-P-phenylphosphinoselenoic Chlo-
ride (1c). A pale-yellow oil. 1H NMR: δ 0.85, 1.04 (d, J ) 7.8
Hz, 3H), 0.94, 1.36 (dd, J ) 6.8 Hz, JHP ) 24.9 Hz, 3H), 1.22-
1.58, 2.03-2.17 (m, 2H), 2.44-2.56 (m, 1H), 7.44-7.57 (m, 3H),
7.95-8.01 (m, 2H); 13C NMR: δ 11.6 (d, JCP ) 18.2 Hz), 11.8
(d, JCP ) 17.4 Hz), 12.8, 13.0, 23.3, 23.5, 46.1 (d, JCP ) 48.0
Hz), 46.2 (d, JCP ) 48.0 Hz), 128.5 (d, JCP ) 13.2 Hz), 128.6
(d, JCP ) 13.2 Hz), 131.71 (d, JCP ) 11.6 Hz), 131.73 (d, JCP
)
11.6 Hz), 132.4 (d, JCP ) 71.1 Hz), 132.5 (d, JCP ) 72.0 Hz),
132.6 (d, JCP ) 3.3 Hz), 132.7 (d, JCP ) 3.3 Hz); 31P NMR: δ
98.7 (JPSe ) 841.9 Hz); 77Se NMR: δ -206.9 (d, JSeP ) 841.9
Hz), -205.0 (d, JSeP ) 841.9 Hz); MS(EI) m/z: 280 (M+); Anal.
Calcd for C10H14ClPSe: C, 42.96; H, 5.05. Found: C, 43.11;
H, 4.96.
(d, JCP ) 1.7 Hz), 16.7, 40.0 (d, JCP ) 49.6 Hz), 128.6 (d, JCP
)
13.2 Hz), 131.8 (d, JCP ) 11.6 Hz), 132.0, 132.7 (d, JCP ) 3.3
Hz); 31P NMR: δ 100.2 (JPSe ) 841.9 Hz); 77Se NMR: δ -219.7
P-(1,1-Dimethylethyl)-P-phenylphosphinoselenoic Chlo-
1
(17) Thompson, D. P.; Boudjouk, P. J. Org. Chem. 1988, 53, 2109.
956 J. Org. Chem., Vol. 70, No. 3, 2005
ride (1d). A colorless solid. mp: 72-74 °C (dec); H NMR: δ

Synthesis of P-Chiral Chlorides and Acid Esters
1.25 (d, JHP ) 21.0 Hz, 9H), 7.45-7.56 (m, 3H), 8.00-8.06 (m,
2H); 13C NMR: δ 24.7 (d, JCP ) 2.5 Hz), 42.7 (d, JCP ) 43.0
Hz), 128.1 (d, JCP ) 12.4 Hz), 130.7 (d, JCP ) 67.0 Hz), 132.4
(d, JCP ) 2.5 Hz), 133.1 (d, JCP ) 10.8 Hz); 31P NMR: δ 111.0
(JPSe ) 837.3 Hz); 77Se NMR: δ -171.5 (d, JSeP ) 837.3 Hz);
MS(EI) m/z: 280 (M+); Anal. Calcd for C10H14ClPSe: C, 42.96;
H, 5.05. Found: C, 42.95; H, 4.87.
to give 1.128 g (46%) of 1h as a colorless solid. mp: 38-41 °C
1
(dec); H NMR: δ 1.22 (dd, J ) 6.8 Hz, JHP ) 21.5 Hz, 3H),
1.36 (dd, J ) 6.8 Hz, JHP ) 20.3 Hz, 3H), 1.38 (d, JHP ) 19.0
Hz, 9H), 2.76 (octet, J ) 6.8 Hz, 1H); 13C NMR: δ 18.8 (d, JCP
) 3.3 Hz), 18.9, 26.1, 35.2 (d, JCP ) 37.2 Hz), 42.3 (d, JCP
)
35.6 Hz); 31P NMR: δ 138.1 (JPSe ) 822.4 Hz); 77Se NMR: δ
-262.3 (d, JSeP ) 822.4 Hz); MS(EI) m/z: 246 (M+); HRMS
calcd for C7H16ClPSe: 245.9843. Found: 245.9817.
General Procedure for the Synthesis of Aryl Phen-
ylphosphinoselenoic Chlorides 1e-g. A Representative
Procedure for the Synthesis of P-(2-Methoxyphenyl)-P-
phenylphosphinoselenoic Chloride (1e). To a suspension
of elemental selenium (0.869 g, 11.0 mmol) in THF (20 mL)
was added PhPCl2 (1.36 mL, 10.0 mmol) at room temperature
under an Ar atmosphere. To this mixture was added o-
AnisMgBr (1.0 mol/L THF solution, 2.00 mL, 2.0 mmol) in THF
(32 mL) dropwise over a period of 1 h at 0 °C with vigorous
stirring. After the solvent was removed, toluene (20 mL) was
added to the residue. The mixture was stirred under reflux in
toluene for 1 h, and the insoluble parts were filtered off. After
the solvent was removed, the residue was purified by column
chromatography on silica gel using n-C6H14/CH2Cl2 as eluent
and gel permeation chromatography using CHCl3 as eluent
to give 0.402 g (61%) of 1e as a colorless solid. mp: 90-92 °C
(dec); 1H NMR: δ 3.59 (s, 3H), 6.87 (t, J ) 7.8 Hz, 1H), 7.10-
7.15 (m, 1H), 7.40-7.50 (m, 3H), 7.52-7.57 (m, 1H), 7.85-
7.91 (m, 2H), 8.14-8.20 (m, 1H); 13C NMR: δ 55.6, 112.2 (d,
JCP ) 6.6 Hz), 120.8 (d, JCP ) 15.7 Hz), 121.7 (d, JCP ) 82.7
Hz), 128.1 (d, JCP ) 14.9 Hz), 130.3 (d, JCP ) 13.2 Hz), 131.8
(d, JCP ) 3.3 Hz), 135.3 (d, JCP ) 12.4 Hz), 135.4 (d, JCP ) 1.7
Hz), 136.5 (d, JCP ) 89.3 Hz), 159.7 (d, JCP ) 2.5 Hz); 31P
P-Cyclohexyl-P-(1,1-dimethylethyl)phosphinoseleno-
ic Chloride (1i). A colorless solid. mp: 61-63 °C (dec); 1H
NMR: δ 1.17-1.43 (m, 3H), 1.37 (d, JHP ) 19.0 Hz, 9H), 1.46-
1.75 (m, 3H), 1.80-1.95 (m, 3H), 2.07-2.13 (m, 1H), 2.37-
2.46 (m, 1H); 13C NMR: δ 25.3, 25.8, 26.0 (d, JCP ) 6.6 Hz),
26.2, 27.3 (d, JCP ) 4.1 Hz), 28.6, 42.4 (d, JCP ) 35.6 Hz), 45.0
(d, JCP ) 35.6 Hz); 31P NMR: δ 133.3 (JPSe ) 817.8 Hz); 77Se
NMR: δ -233.5 (d, JSeP ) 817.8 Hz); MS(EI) m/z: 286 (M+);
Anal. Calcd for C10H20ClPSe: C, 42.05; H, 7.06. Found: C,
42.22; H, 6.77.
General Procedure for the Synthesis of Phosphino-
selenoic Acid O-Esters 2. A Representative Procedure
for the Synthesis of P-(1,1-Dimethylethyl)-P-phenylphos-
phinoselenoic Acid O-Ethyl Ester (2a). To a EtOH solution
(5 mL) of EtONa (0.137 g, 2.00 mmol) was added P-(1,1-
dimethylethyl)-P-phenylphosphinoselenoic chloride (1d) (0.280
g, 1.00 mmol) at room temperature, and the mixture was
stirred under reflux for 3 h. The reaction mixture was poured
onto water and extracted with Et2O (20 mL). The organic layer
was dried over MgSO4 and concentrated in vacuo. The residue
was purified by column chromatography on silica gel using
n-C6H14/Et2O as eluent to give 0.283 g (98%) of 2a as a pale-
NMR: δ 66.3 (JPSe ) 840.4 Hz); 77Se NMR: δ -48.4 (d, JSeP
)
1
yellow oil. H NMR: δ 1.13 (d, JHP ) 18.1 Hz, 9H), 1.32 (t, J
840.4 Hz); MS(EI) m/z: 330 (M+); HRMS calcd for C13H12-
ClOPSe: 329.9480. Found: 329.9478.
) 7.0 Hz, 3H), 3.81-3.91 (m, 1H), 4.17-4.27 (m, 1H), 7.40-
7.49 (m, 3H), 7.79-7.84 (m, 2H); 13C NMR: δ 16.1 (d, JCP
)
P-(4-Methylphenyl)-P-phenylphosphinoselenoic Chlo-
ride (1f). A pale-yellow oil. 1H NMR: δ 2.40 (s, 3H), 7.28 (dd,
J ) 8.1 Hz, JHP ) 3.9 Hz, 2H), 7.43-7.53 (m, 3H), 7.82 (dd, J
) 8.1 Hz, JHP ) 15.6 Hz, 2H), 7.88-7.95 (m, 2H); 13C NMR:
δ 21.5, 128.5 (d, JCP ) 14.1 Hz), 129.3 (d, JCP ) 14.9 Hz), 131.0
7.4 Hz), 24.5, 36.9 (d, JCP ) 65.3 Hz), 62.9 (d, JCP ) 7.4 Hz),
127.9 (d, JCP ) 11.6 Hz), 131.6 (d, JCP ) 77.8 Hz), 131.7 (d,
JCP ) 3.3 Hz), 132.7 (d, JCP ) 9.9 Hz); 31P NMR: δ 111.0 (JPSe
) 786.3 Hz); 77Se NMR: δ -350.3 (d, JSeP ) 786.3 Hz); MS-
(EI) m/z: 290 (M+); Anal. Calcd for C12H19OPSe: C, 49.83; H,
6.62. Found: C, 49.78; H, 6.68.
(d, JCP ) 13.2 Hz), 131.3 (d, JCP ) 13.2 Hz), 131.8 (d, JCP
)
86.1 Hz), 132.4 (d, JCP ) 3.3 Hz), 135.6 (d, JCP ) 84.4 Hz),
143.5 (d, JCP ) 3.3 Hz); 31P NMR: δ 72.1 (JPSe ) 846.4 Hz);
77Se NMR: δ -68.4 (d, JSeP ) 846.4 Hz); MS(EI) m/z: 314 (M+);
HRMS calcd for C13H12ClPSe: 313.9530. Found: 313.9523.
P-Cyclohexyl-P-phenylphosphinoselenoic Acid O-Eth-
yl Ester (2b). A pale-yellow oil. 1H NMR: δ 1.11-1.50 (m,
5H), 1.28 (t, J ) 6.8 Hz, 3H), 1.54-1.85 (m, 4H), 2.00-2.12
(m, 2H), 3.73-3.83 (m, 1H), 4.10-4.21 (m, 1H), 7.45-7.54 (m,
3H), 7.85-7.90 (m, 2H); 13C NMR: δ 16.0 (d, JCP ) 8.3 Hz),
25.3, 25.6, 25.7, 25.8 (d, JCP ) 5.0 Hz), 25.9 (d, JCP ) 6.6 Hz),
P-(4-Chlorophenyl)-P-phenylphosphinoselenoic Chlo-
1
ride (1g). A pale-yellow oil. H NMR: δ 7.43-7.57 (m, 5H),
7.82-7.95 (m, 4H); 13C NMR: δ 128.7 (d, JCP ) 13.2 Hz), 128.9
44.0 (d, JCP ) 68.7 Hz), 62.0 (d, JCP ) 6.6 Hz), 128.1 (d, JCP )
(d, JCP ) 14.9 Hz), 131.1 (d, JCP ) 13.2 Hz), 132.5 (d, JCP
)
12.4 Hz), 131.8, 131.9 (d, JCP ) 6.6 Hz), 132.7; 31P NMR: δ
102.9 (JPSe ) 781.7 Hz); 77Se NMR: δ -359.3 (d, JSeP ) 781.7
Hz); MS(EI) m/z: 316 (M+); Anal. Calcd for C14H21OPSe: C,
53.34; H, 6.71. Found: C, 53.36; H, 6.51.
14.1 Hz), 132.8 (d, JCP ) 3.3 Hz), 133.9 (d, JCP ) 86.8 Hz),
134.9 (d, JCP ) 85.2 Hz), 139.3 (d, JCP ) 3.3 Hz); 31P NMR: δ
69.6 (JPSe ) 853.9 Hz); 77Se NMR: δ -67.3 (d, JSeP ) 853.9
Hz); MS(EI) m/z: 334 (M+); HRMS calcd for C12H9Cl2PSe:
333.8984. Found: 333.8988.
General Procedure for the Synthesis of Phosphino-
selenothioic Acid S-Esters 3. A Representative Proce-
dure for the Synthesis of P-(1,1-Dimethylethyl)-P-phen-
ylphosphinoselenothioic Acid S-Butyl Ester (3a). To a
THF solution (5 mL) of 1-butanethiol (118 µL, 1.10 mmol) was
added n-BuLi (1.6 mol/L hexane solution, 0.625 mL, 1.0 mmol)
at 0 °C, and the mixture was stirred at that temperature for
10 min. P-(1,1-Dimethylethyl)-P-phenylphosphinoselenoic chlo-
ride (1d) (0.280 g, 1.00 mmol) was then added at 0 °C, and
the mixture was stirred at that temperature for 1 h. The
reaction mixture was poured onto water and extracted with
Et2O (20 mL). The organic layer was dried over MgSO4 and
concentrated in vacuo. The residue was purified by column
chromatography on silica gel using n-C6H14/Et2O as eluent to
give 0.317 g (95%) of 3a as a colorless oil. 1H NMR: δ 0.82 (t,
J ) 7.3 Hz, 3H), 1.21 (d, JHP ) 19.0 Hz, 9H), 1.35 (sextet, J )
7.3 Hz, 2H), 1.48-1.56 (m, 2H), 2.73-2.94 (m, 2H), 7.40-7.48
(m, 3H), 8.05-8.10 (m, 2H); 13C NMR: δ 13.5, 21.8, 25.2, 32.1
(d, JCP ) 5.0 Hz), 33.0 (d, JCP ) 2.5 Hz), 38.1 (d, JCP ) 43.0
Hz), 127.9 (d, JCP ) 11.6 Hz), 130.8 (d, JCP ) 58.7 Hz), 131.5
(d, JCP ) 3.3 Hz), 133.5 (d, JCP ) 9.1 Hz); 31P NMR: δ 88.0
(JPSe ) 763.7 Hz); 77Se NMR: δ -310.8 (d, JSeP ) 763.7 Hz);
General Procedure for the Synthesis of Alkyl (1,1-
Dimethylethyl)phosphinoselenoic Chlorides 1h and 1i.
A Representative Procedure for the Synthesis of P-(1-
Methylethyl)-P-(1,1-dimethylethyl)phosphinoselenoic
Chloride (1h). To a suspension of elemental selenium (0.868
g, 11.0 mmol) in THF (50 mL) was added PCl3 (0.872 mL, 10.0
mmol) at room temperature under an Ar atmosphere. To this
mixture was added t-BuMgCl (1.0 M solution in THF, 10.0 mL,
10 mmol) in THF (40 mL) dropwise over a period of 1 h at 0
°C with vigorous stirring. The reaction mixture was stirred
at room temperature for 2 h. To this mixture was added
i-PrMgCl (2.0 M solution in Et2O, 5.00 mL, 10 mmol) in THF
(45 mL) dropwise over a period of 1 h at 0 °C with vigorous
stirring. The reaction mixture was stirred at room temperature
for 2 h. After the solvent was removed, toluene (25 mL) was
added to the residue. The mixture was stirred under reflux in
toluene for 1 h, and the insoluble parts were filtered off. After
the solvent was removed, the residue was purified by column
chromatography on silica gel using n-C6H14/CH2Cl2 as eluent
and gel permeation chromatography using CHCl3 as eluent
J. Org. Chem, Vol. 70, No. 3, 2005 957

Kimura and Murai
MS(EI) m/z 334 (M+); Anal. Calcd for C14H23PSSe: C, 50.45;
P-(1,1-Dimethylethyl)-P-phenylphosphinodiselenoic
Acid Phenyl Ester (4c). A pale-yellow solid. mp: 95-98 °C
H, 6.95. Found: C, 50.17; H, 7.04.
1
(dec); H NMR: δ 1.33 (d, JHP ) 19.0 Hz, 9H), 7.22-7.28 (m,
P-(1-Methylethyl)-P-phenylphosphinoselenothioic Acid
1
2H), 7.32-7.41 (m, 1H), 7.44-7.51 (m, 5H), 8.16-8.21 (m, 2H);
13C NMR: δ 25.9 (d, JCP ) 1.7 Hz), 39.6 (d, JCP ) 34.7 Hz),
125.0 (d, JCP ) 5.8 Hz), 127.9 (d, JCP ) 11.6 Hz), 128.9 (d, JCP
) 1.7 Hz), 129.4 (d, JCP ) 1.7 Hz), 129.8 (d, JCP ) 52.1 Hz),
131.5 (d, JCP ) 2.5 Hz), 134.1 (d, JCP ) 9.1 Hz), 137.4 (d, JCP
) 3.3 Hz); 31P NMR: δ 85.7 (JPSe ) 371.4, 774.2 Hz); 77Se
NMR: δ -239.6 (d, JSeP ) 774.2 Hz), 365.4 (d, JSeP ) 371.4
Hz); MS(EI) m/z: 402 (M+); Anal. Calcd for C16H19PSe2: C,
48.02; H, 4.79. Found: C, 47.76; H, 4.69.
S-Butyl Ester (3b). A colorless oil. H NMR: δ 0.82 (t, J )
7.3 Hz, 3H), 1.00 (dd, J ) 6.8 Hz, JHP ) 21.5 Hz, 3H), 1.30
(dd, J ) 6.8 Hz, JHP ) 21.0 Hz, 3H), 1.29-1.39 (m, 2H), 1.47-
1.54 (m, 2H), 2.43-2.55 (m, 1H), 2.73-2.92 (m, 2H), 7.44-
7.52 (m, 3H), 8.01-8.07 (m, 2H); 13C NMR: δ 13.5, 16.7, 17.1,
21.7, 32.1 (d, JCP ) 4.1 Hz), 32.5 (d, JCP ) 2.5 Hz), 35.5 (d, JCP
) 48.0 Hz), 128.3 (d, JCP ) 12.4 Hz), 131.7 (d, JCP ) 2.5 Hz),
132.1 (d, JCP ) 10.8 Hz), 132.2 (d, JCP ) 63.7 Hz); 31P NMR:
δ 77.5 (JPSe ) 768.2 Hz); 77Se NMR: δ -355.0 (d, JSeP ) 768.2
Hz); MS(EI) m/z 320 (M+); Anal. Calcd for C13H21PSSe: C,
48.90; H, 6.63. Found: C, 48.88; H, 6.64.
Synthesis of P-(1,1-Dimethylethyl)-P-phenylphos-
phinodiselenoic Acid Methyl Ester (4d). To a CH3CN
suspension (5 mL) of Na2Se (0.069 g, 0.55 mmol) was added
P-(1,1-dimethylethyl)-P-phenylphosphinoselenoic chloride (1d)
(0.140 g, 0.50 mmol) at 0 °C, and the mixture was stirred at
that temperature for 4 h. After the insoluble parts were filtered
off, MeI (62 µL, 1.0 mmol) was added to the filtrate at 0 °C,
and the mixture was stirred at that temperature for 1 h. The
reaction mixture was poured onto water and extracted with
Et2O (20 mL). The organic layer was dried over MgSO4 and
concentrated in vacuo. The residue was purified by column
chromatography on silica gel using n-C6H14/Et2O as eluent to
give 0.159 g (94%) of 4d as a pale-yellow oil. 1H NMR: δ 1.23
(d, JHP ) 19.5 Hz, 9H), 2.18 (d, JHP ) 12.2 Hz, 3H), 7.40-7.48
(m, 3H), 8.05-8.11 (m, 2H); 13C NMR: δ 9.2 (d, JCP ) 2.5 Hz),
P-(1,1-Dimethylethyl)-P-phenylphosphinoselenothio-
ic Acid S-Phenyl Ester (3c). A colorless solid. mp: 120-
1
125 °C (dec); H NMR: δ 1.31 (d, JHP ) 18.5 Hz, 9H), 7.22-
7.51 (m, 8H), 8.16-8.21 (m, 2H); 13C NMR: δ 25.7, 39.1 (d,
JCP ) 40.5 Hz), 127.2 (d, JCP ) 5.0 Hz), 127.9 (d, JCP ) 11.6
Hz), 128.9 (d, JCP ) 2.5 Hz), 129.6 (d, JCP ) 2.5 Hz), 130.1 (d,
JCP ) 57.1 Hz), 131.6 (d, JCP ) 3.3 Hz), 134.1 (d, JCP ) 9.9
Hz), 136.8 (d, JCP ) 4.1 Hz); 31P NMR: δ 93.5 (JPSe ) 783.2
Hz); 77Se NMR: δ -279.3 (d, JSeP ) 783.2 Hz); MS(EI) m/z:
354 (M+); HRMS calcd for C16H19PSSe: 354.0110. Found:
354.0087.
P-(1,1-Dimethylethyl)-P-phenylphosphinoselenothio-
ic Acid S-[2-(Trimethylsilyl)ethyl] Ester (3d). A colorless
1
25.6 (d, JCP ) 2.5 Hz), 39.0 (d, JCP ) 36.4 Hz), 128.0 (d, JCP )
solid. mp: 45-47 °C (dec); H NMR: δ -0.05 (s, 9H), 0.81-
11.6 Hz), 129.8 (d, JCP ) 52.9 Hz), 131.6 (d, JCP ) 3.3 Hz),
133.7 (d, JCP ) 9.1 Hz); 31P NMR: δ 82.6 (JPSe ) 366.2, 762.9
Hz); 77Se NMR: δ -279.7 (d, JSeP ) 762.9 Hz), 112.6 (d, JSeP
) 366.2 Hz); MS(EI) m/z: 340 (M+); Anal. Calcd for C11H17-
PSe2: C, 39.07; H, 5.07. Found: C, 39.28; H, 4.91.
0.96 (m, 2H), 1.20 (d, JHP ) 19.0 Hz, 9H), 2.75-2.84 (m, 1H),
2.93-3.04 (m, 1H), 7.40-7.48 (m, 3H), 8.05-8.11 (m, 2H); 13
C
NMR: δ -1.7, 18.8 (d, JCP ) 5.0 Hz), 25.2, 30.3 (d, JCP ) 3.3
Hz), 38.1 (d, JCP ) 41.4 Hz), 128.9 (d, JCP ) 11.6 Hz), 130.9
(d, JCP ) 57.9 Hz), 131.4 (d, JCP ) 3.3 Hz), 133.5 (d, JCP ) 9.9
Hz); 31P NMR: δ 86.1 (JPSe ) 762.2 Hz); 77Se NMR: δ -311.5
(d, JSeP ) 762.2 Hz); MS(EI) m/z: 378 (M+); Anal. Calcd for
C15H27PSSeSi: C, 47.73; H, 7.21. Found: C, 47.45; H, 6.91.
General Procedure for the Synthesis of Phosphino-
selenoic Acid Se-Esters 8. A Representative Procedure
for the Synthesis of P-(1,1-Dimethylethyl)-P-phenylphos-
phinoselenoic Acid Se-Methyl Ester (8a). To a CH3CN
suspension (5 mL) of NaOH (0.389 g, 9.7 mmol) was added
P-(1,1-dimethylethyl)-P-phenylphosphinoselenoic chloride (1d)
(0.280 g, 1.00 mmol) at room temperature, and the mixture
was stirred at that temperature for 24 h. After the insoluble
parts were filtered off, MeI (125 µL, 2.0 mmol) was added to
the filtrate at room temperature, and the mixture was stirred
at that temperature for 1 h. The reaction mixture was poured
onto water and extracted with CH2Cl2 (20 mL). The organic
layer was dried over MgSO4 and concentrated in vacuo. The
residue was purified by column chromatography on silica gel
using CHCl3/MeOH as eluent to give 0.270 g (98%) of 8a as a
General Procedure for the Synthesis of Phosphino-
diselenoic Acid Esters 4. A Representative Procedure
for the Synthesis of P-(1,1-Dimethylethyl)-P-phenylphos-
phinodiselenoic Acid Butyl Ester (4a). To a THF suspen-
sion (5 mL) of elemental selenium (0.079 g, 1.0 mmol) was
added n-BuLi (1.6 mol/L hexane solution, 0.625 mL, 1.0 mmol)
at 0 °C, and the mixture was stirred at that temperature for
10 min. P-(1,1-Dimethylethyl)-P-phenylphosphinoselenoic chlo-
ride (1d) (0.252 g, 0.90 mmol) was then added, and the mixture
was stirred at that temperature for 15 min. The reaction
mixture was poured onto water and extracted with Et2O (20
mL). The organic layer was dried over MgSO4 and concen-
trated in vacuo. The residue was purified by column chroma-
tography on silica gel using n-C6H14/Et2O as eluent to give
0.330 g (96%) of 4a as a pale-yellow oil. 1H NMR: δ 0.81 (t, J
) 6.8 Hz, 3H), 1.21 (d, JHP ) 18.5 Hz, 9H), 1.34 (sextet, J )
7.3 Hz, 2H), 1.52-1.60 (m, 2H), 2.91-2.97 (m, 2H), 7.38-7.46
(m, 3H), 8.06-8.11 (m, 2H); 13C NMR: δ 13.5, 22.9, 25.5 (d,
JCP ) 2.5 Hz), 31.1 (d, JCP ) 2.5 Hz), 32.4 (d, JCP ) 3.3 Hz),
38.7 (d, JCP ) 37.2 Hz), 127.8 (d, JCP ) 11.6 Hz), 130.8 (d, JCP
) 52.1 Hz), 131.4 (d, JCP ) 2.5 Hz), 133.7 (d, JCP ) 9.9 Hz);
31P NMR: δ 79.9 (JPSe ) 381.9, 756.2 Hz); 77Se NMR: δ -277.8
(d, JSeP ) 756.2 Hz), 181.4 (d, JSeP ) 381.9 Hz); MS(EI) m/z:
382 (M+); Anal. Calcd for C14H23PSe2: C, 44.22; H, 6.10.
Found: C, 44.41; H, 6.16.
1
pale-yellow oil. H NMR: δ 1.13 (d, JHP ) 17.6 Hz, 9H), 1.97
(d, JHP ) 9.3 Hz, 3H), 7.39-7.49 (m, 3H), 7.80-7.87 (m, 2H);
13C NMR: δ 2.1 (d, JCP ) 2.5 Hz), 24.7, 37.7 (d, JCP ) 62.9
Hz), 128.1 (d, JCP ) 12.4 Hz), 131.4 (d, JCP ) 81.9 Hz), 131.9
(d, JCP ) 3.3 Hz), 132.6 (d, JCP ) 9.1 Hz); 31P NMR: δ 68.2
(JPSe ) 390.9 Hz); 77Se NMR: δ 54.4 (d, JSeP ) 390.9 Hz); MS
(EI) m/z: 276 (M+); Anal. Calcd for C11H17OPSe: C, 48.01; H,
6.23. Found: C, 47.84; H, 6.23.
P-Cyclohexyl-P-phenylphosphinoselenoic Acid Se-
Ethyl Ester (8b). A colorless solid. 1H NMR: δ 1.11-1.52 (m,
5H), 1.34 (t, J ) 7.3 Hz, 3H), 1.68-1.86 (m, 4H), 1.99-2.07
(m, 2H), 2.68-2.84 (m, 2H), 7.47-7.55 (m, 3H), 7.82-7.87 (m,
2H); 13C NMR: δ 16.6 (d, JCP ) 3.3 Hz), 17.6 (d, JCP ) 1.7
Hz), 25.5, 25.6 (d, JCP ) 2.5 Hz), 25.7 (d, JCP ) 2.5 Hz), 25.9,
26.0, 44.0 (d, JCP ) 64.5 Hz), 128.2 (d, JCP ) 12.4 Hz), 131.3
(d, JCP ) 9.9 Hz), 131.6 (d, JCP ) 2.5 Hz), 133.1 (d, JCP ) 85.2
Hz); 31P NMR: δ 55.9 (JPSe ) 387.8 Hz); 77Se NMR: δ 199.3
(d, JSeP ) 387.8 Hz); MS(EI) m/z: 316 (M+); Anal. Calcd for
C14H21OPSe: C, 53.34; H, 6.71. Found: C, 53.25; H, 6.69.
General Procedure for the Synthesis of Phosphino-
selenothioic Acid Se-Esters 9. A Representative Proce-
dure for the Synthesis of P-(1,1-Dimethylethyl)-P-phen-
ylphosphinoselenothioic Acid Se-Methyl Ester (9a). To
a CH3CN suspension (5 mL) of Na2S (0.390 g, 5.0 mmol) was
P-(1,1-Dimethylethyl)-P-phenylphosphinodiselenoic
Acid 1,1-Dimethylethyl Ester (4b). A pale-yellow solid.
mp: 102-105 °C (dec); 1H NMR: δ 1.17 (d, JHP ) 19.0 Hz,
9H), 1.51 (d, JHP ) 1.0 Hz, 9H), 7.41-7.44 (m, 3H), 8.19-8.25
(m, 2H); 13C NMR: δ 25.5, 33.1, 39.4 (d, JCP ) 37.2 Hz), 53.1
(d, JCP ) 4.1 Hz), 127.6 (d, JCP ) 11.6 Hz), 130.8 (d, JCP
)
50.5 Hz), 131.2 (d, JCP ) 2.5 Hz), 134.2 (d, JCP ) 9.9 Hz); 31P
NMR: δ 65.8 (JPSe ) 420.9, 745.6 Hz); 77Se NMR: δ -237.8
(d, JSeP ) 745.6 Hz), 385.2 (d, JSeP ) 420.9 Hz); MS(EI) m/z:
382 (M+); Anal. Calcd for C14H23PSe2: C, 44.22; H, 6.10.
Found: C, 44.22; H, 5.97.
958 J. Org. Chem., Vol. 70, No. 3, 2005

Synthesis of P-Chiral Chlorides and Acid Esters
added P-(1,1-dimethylethyl)-P-phenylphosphinoselenoic chlo-
ride (1d) (0.280 g, 1.00 mmol) at room temperature, and the
mixture was stirred at that temperature for 6 h. After the
insoluble parts were filtered off, MeI (125 µL, 2.0 mmol) was
added to the filtrate at room temperature, and the mixture
was stirred at that temperature for 1 h. The reaction mixture
was poured onto water and extracted with Et2O (20 mL). The
organic layer was dried over MgSO4 and concentrated in vacuo.
The residue was purified by column chromatography on silica
gel using n-C6H14/Et2O as eluent to give 0.261 g (90%) of 9a
7.44-7.52 (m, 3H), 7.96-8.02 (m, 2H); 13C NMR: δ 13.5, 16.4,
16.8, 22.9, 28.3 (d, JCP ) 2.5 Hz), 32.7 (d, JCP ) 3.3 Hz), 36.6
(d, JCP ) 49.6 Hz), 128.4 (d, JCP ) 12.4 Hz), 131.4 (d, JCP
)
9.9 Hz), 131.5 (d, JCP ) 3.3 Hz), 133.6 (d, JCP ) 67.0 Hz); 31P
NMR: δ 72.5 (JPSe ) 366.8 Hz); 77Se NMR: δ 234.5 (d, JSeP
)
366.8 Hz); MS(EI) m/z: 320 (M+); Anal. Calcd for C13H21-
PSSe: C, 48.90; H, 6.63. Found: C, 49.15; H, 6.41.
Acknowledgment. This research was supported by
a Grant-in-Aid for Scientific Research on Priority Area
(No. 16033224, ‘‘Reaction Control of Dynamic Com-
plexes”) from the Ministry of Education, Culture, Sports,
Science and Technology of Japan.
1
as a pale-yellow oil. H NMR: δ 1.23 (d, JHP ) 19.0 Hz, 9H),
2.19 (d, JHP ) 11.2 Hz, 3H), 7.43-7.52 (m, 3H), 8.03-8.09 (m,
2H); 13C NMR: δ 6.7 (d, JCP ) 3.3 Hz), 25.3, 39.6 (d, JCP
)
44.6 Hz), 128.0 (d, JCP ) 11.6 Hz), 131.1 (d, JCP ) 62.9 Hz),
131.6 (d, JCP ) 3.1 Hz), 133.2 (d, JCP ) 8.3 Hz); 31P NMR: δ
88.3 (JPSe ) 366.8 Hz); 77Se NMR: δ 108.2 (d, JSeP ) 366.8
Hz); MS(EI) m/z: 292 (M+); HRMS calcd for C11H17PSSe:
291.9954. Found: 291.9928.
Supporting Information Available: Copies of 1H and 13
C
NMR spectra for compounds 1a, 1e-h, 3c, and 9a, tables of
crystallographic data including atomic positional and thermal
parameters for 1b, 3d, and 4c, Z matrixes of optimized
structures for 2′-4′, 8′, and 9′. This material is available free
of charge via the Internet at http://pubs.acs.org.
P-(1-Methylethyl)-P-phenylphosphinoselenothioic Acid
Se-Butyl Ester (9b). A colorless oil. 1H NMR: δ 0.83 (t, J )
7.6 Hz, 3H), 1.03 (dd, J ) 6.8 Hz, JHP ) 21.0 Hz, 3H), 1.26-
1.38 (m, 2H), 1.32 (dd, J ) 6.8 Hz, JHP ) 21.5 Hz, 3H), 1.55-
1.62 (m, 2H), 2.49 (sextet, J ) 6.8 Hz, 1H), 2.86-2.99 (m, 2H),
JO0484979
J. Org. Chem, Vol. 70, No. 3, 2005 959