Synthesis of bis(trimethylstannyl)aryl compounds via an SRN1 mechanism with intermediacy of monosubstitution products

Article abstract of DOI:10.1021/om020622o

1,2-Bis(trimethylstannyl)benzene (1) and 2,2′-bis(trimethylstannyl)-1,1′-binaphthyl (2), useful as intermediates in the preparation of bidentate Lewis acids, have been synthesized from simple phenols through a two-step sequence. Thus, 2-chlorophenol, 1,2-dihydroxybenzene, and binaphthol were converted into the corresponding aryl diethyl phosphate esters 4-6, which on reaction with sodium trimethylstannide (3) in liquid ammonia, under irradiation, afforded 1 and 2, respectively, in good yields (66-82%). The results obtained clearly indicate that the reactions proceed through an S_RN1 mechanism and involve the intermediacy of a monosubstitution product.

Full text of DOI:10.1021/om020622o

5874
Organometallics 2002, 21, 5874-5878
Syn th esis of Bis(tr im eth ylsta n n yl)a r yl Com p ou n d s via
a n SRN1 Mech a n ism w ith In ter m ed ia cy of
Mon osu bstitu tion P r od u cts
Alicia B. Chopa,* Mar´ıa T. Lockhart, and Gustavo F. Silbestri
INIQO, Departamento de Quı´mica, Universidad Nacional del Sur, Avda. Alem 1253,
8000 Bahı´a Blanca, Argentina
Received J uly 31, 2002
1,2-Bis(trimethylstannyl)benzene (1) and 2,2′-bis(trimethylstannyl)-1,1′-binaphthyl (2),
useful as intermediates in the preparation of bidentate Lewis acids, have been synthesized
from simple phenols through a two-step sequence. Thus, 2-chlorophenol, 1,2-dihydroxyben-
zene, and binaphthol were converted into the corresponding aryl diethyl phosphate esters
4-6, which on reaction with sodium trimethylstannide (3) in liquid ammonia, under
irradiation, afforded 1 and 2, respectively, in good yields (66-82%). The results obtained
clearly indicate that the reactions proceed through an SRN1 mechanism and involve the
intermediacy of a monosubstitution product.
In tr od u ction
reaction of 2,2′-dilithio-1,1′-binaphthyl with excess Me3-
SnCl at -78 °C (87%, 12 h).
In recent years the synthesis of multidentate Lewis
acids has been a subject of growing interest. Studies
carried out by J urkschat et al.1 have demonstrated that
1,2-bis(haloorganostannyl)benzenes work as powerful
bidentate Lewis acids toward halide ions. On the other
hand, preliminary work carried out by Kuivila et al.2
showed that 2,2′-binaphthyl-substituted organotin Lewis
acids are interesting molecules, taking into account that
the rotation about the C(1)-C(1′) bond should allow the
two metal centers to interact with ligands of different
size. The haloorganostannyl derivatives studied by both
groups were synthesized from the corresponding bis-
(trimethylstannyl) compounds through methyl/chlorine
exchange reactions.
The methods available for the synthesis of such bis-
(trimethyltin) compounds are relatively limited. Thus,
the preparation of 1,2-bis(trimethylstannyl)benzene (1)
was first described by Seyferth in 1966, via a Diels-
Alder reaction between bis(trimethylstannyl)ethyne and
R-pyrone in 51% yield.3 Kuivila synthesized 1 (42%) by
the reaction of 1,2-dibromobenzene with Me3SnNa in
tetraglyme.4 This procedure was modified by J urschat,1
who obtained 1 in 67% yield by the reaction (42 h) of
1,2-dichlorobenzene with Me3SnNa in THF. Recently,
Rossi5 reported that the photostimulated reaction of 1,2-
dichlorobenzene with Me3SnNa in liquid ammonia af-
forded the disubstitution product 1 in 58% yield, to-
gether with trimethylphenylstannane (35%).
We have proved that haloarenes and haloheteroare-
nes,6 aryl- and heteroaryl diethyl phosphates,7,8 and
aryl- and heteroaryl trimethylammonium salts9 could
be excellent starting materials for the synthesis of
mono-, di-, and tristannylated substrates by an SRN1
mechanism. The main advantage of these reactions is
that they enable the direct synthesis of organostannanes
with different aryl ligands, avoiding the use of organo-
magnesium or organolithium reagents.
The fact that aryl diethyl phosphate esters containing
two nucleofuges have been shown to react quite ef-
ficiently with trimethyltin sodium (Me3SnNa; 3) by the
SRN1 mechanism, leading to the corresponding distan-
nylated products,8 prompted us to study the scope of this
reaction in the synthesis of compounds 1 and 2. The
present work describes the synthesis of 1 and 2 by a
photochemically induced reaction between aryl diethyl
phosphate esters and 3 in liquid ammonia and some
important mechanistic aspects of these reactions.
Resu lts a n d Discu ssion
We studied the reaction of 2-(chlorophenyl) diethyl
phosphate (4), 1,2-phenylene bis-(diethyl phosphate) (5)
and 2,2′-bis(diethylphosphoxy)-1,1′-binaphthyl (6) with
3 in liquid ammonia.
The results obtained using compounds 4 and 5 are
summarized in Table 1. The photostimulated reaction
of 4 with 3 (1/2.2 ratio) proceeded smoothly (1.5 h) to
afford 1,2-bis(trimethylstannyl)benzene (1)10 in 63%
yield (entry 1). When this reaction was carried out in
On the other hand, 2,2′-bis(trimethylstannyl)-1,1′-
binaphthyl (2) has been prepared by Kuivila2 by the
* Member of CIC. To whom correspondence should be addressed.
E-mail: abchopa@uns.edu.ar.
(1) Altmann, R.; J urkschat, K.; Schu¨rman, M.; Dakternieks, D.;
Duthie, A. Organometallics 1998, 17, 5858 and references therein.
(2) Krishnamurti, R.; Kuivila, H. G.; Shaik, N. S.; Zubieta, J .
Organometallics 1991, 10, 423.
(6) Lockhart, M. T.; Chopa, A. B.; Rossi, R. A. J . Organomet. Chem.
1999, 582, 229.
(7) Chopa, A. B.; Lockhart, M. T.; Silbestri, G. Organometallics 2000,
19, 2249.
(8) Chopa, A. B.; Lockhart, M. T.; Dorn, V. B. Organometallics 2002,
21, 1425.
(3) Evnin, A. B.; Seyferth, D. J . Am. Chem. Soc. 1966, 89, 952.
(4) Wursthorn, K. R.; Kuivila, H. G. J . Organomet. Chem. 1977, 140,
29.
(9) Chopa, A. B.; Lockhart, M. T.; Silbestri, G. Organometallics 2001,
20, 3358.
(10) NMR spectroscopic data are in agreement with those reported
(5) Co´rsico, E. F.; Rossi, R. A. Synlett 2000, 227.
in the literature.1
10.1021/om020622o CCC: $22.00 © 2002 American Chemical Society
Publication on Web 11/16/2002

Bis(trimethylstannyl)aryl Compounds
Organometallics, Vol. 21, No. 26, 2002 5875
Ta ble 1. Rea ction s of 1,2-Disu bstitu ted Ar yl
Dieth yl P h osp h a tes (Ar DEP ) w ith Me3Sn Na in
Liqu id Am m on ia a
Sch em e 1
substrate conditions 2-(Me3Sn)phenyl- 1,2-(Me3Sn)-
entry (amt, mM) (time, min)
DEP (%)b
C6H5 (%)b
1
2
3
4
5
6
7
8
4 (5.88)
4 (5.88)
4 (5.88)
4 (5.88)
4 (5.88)
hν (90)
0
12
0
39
15
36
45
0
0
0
0
0
63c
dark (90)
dark (90)e
hν (15)
df
0
11f
df
hν (5)
4 (11.89)g hν (90)
<3
6
4 (5.88)g
4 (1.78)g
hν (90)
hν (90)
50
66c
50i
0
h
9
4 (5.88
hν (90)
10
11
12
13
14
4 (1.78)
5 (5.88)
5 (5.88)
5 (5.88)
5 (5.88)h
hν (90)
dark (210)
hν (210)
hν (90)
67c
21f
65
36
0
hν (210)
a
b
Substrate/Me3SnNa ) 1/2.2, except where stated. Deter-
mined by GC. c Together with traces of Me3SnC6H5. Small
d
amount not quantified. e 20% p-DNB added. f Together with traces
of phenylDEP. g Substrate/Me3SnNa ) 1/1. Substrate/Me3SnNa
h
i
) 1/5. Together with Me3SnC6H5 (9, 19%).
the dark (same time period), we found that there was a
slow reaction between 4 and 3, giving a mixture of the
monostannylated compound [(2-trimethylstannyl)phe-
nyl] diethyl phosphate (8) (12%), traces of 1, and
substantial amounts of starting substrate (entry 2). This
reaction was totally inhibited by the addition of p-
dinitrobenzene (p-DNB) (20%), a well-known inhibitor
of SRN1 reactions,11 recovering unreacted starting mate-
rial (entry 3). It should be noted that in the photostimu-
lated reaction, after 90 min, no monosubstitution prod-
uct 8 was detected. Nevertheless, when the reaction
between 4 and 3 was quenched at shorter times (15
min), a mixture of monostannylated compound 8 (39%)
and distannylated compound 1 (11%) together with
starting material was obtained (entry 4). Under similar
conditions, after 5 min irradiation, the reaction led to a
mixture of 8 in about 15% yield, traces of 1, and about
80% of unreacted 4 (entry 5). The yield of 1 progressively
increased with time at the expense of 8, and after 90
min 1 was the only product, with complete consumption
of the substrate. These results constitute evidence that
8 is an intermediate in the transformation of 4 into 1.
Also, the formation of 8 indicates that chlorine is the
first nucleofuge replaced in the reaction. This is in
accord with the fact that chlorobenzene is more reactive
than phenyl diethyl phosphate toward 3 in liquid
ammonia.12 The fact that the reaction between 4 and 3
is stimulated by irradiation and that the slow reaction
in the dark is suppressed by p-DNB indicates the
radical-chain character of the substitution process.
These results suggest that the reaction occurs by the
reaction indicates that step 2 is faster than step 1 under
the conditions employed. In a second propagation cycle,
compound 8 is capable of reacting with nucleophile 3,
leading at last to disubstitution product 1. It should be
noted that step 1 is unimolecular but step 2 is bimo-
lecular, depending on the concentration of substrate. To
determine if substrate concentration affects the absolute
rate of step 2, we carried out a series of reactions with
different substrate concentrations using an insufficient
amount of 3 (1/1 ratio). Our results confirm that a larger
amount of monostannylated product is formed at higher
concentration of substrate.13 Thus, a larger ratio 8/1
(13/1) is obtained at higher substrate concentration and
this ratio drops to 7/1 and finally to 0/100 as the
substrate concentration diminishes (entries 6-8). The
fact that compound 8 is not detected at lower concentra-
tions suggests that under these reaction conditions step
1 competes efficiently with step 2. The conditions
S
RN1 mechanism, through two propagation cycles, as
sketched in Scheme 1.
The radical anion 8•- may suffer two competing
reactions: electron transfer to 4, which furnishes the
monosubstitution product 8 (step 2), or bond fragmenta-
tion to expel diethyl phosphate anion, leading to radical
9• (step 1), which ultimately leads to disubstitution
product 1. The formation of 8 as an intermediate in this
(11) Rossi, R. A.; de Rossi, R. H. Aromatic Substitution by the SRN1
Mechanism; ACS Monograph 178; American Chemical Society: Wash-
ington, DC, 1983.
(13) These results are in agreement with those obtained by Bunnett
in the reaction between m-chloroiodobenzene and diethyl phosphite
ion: Bunnett, J . F.; Shafer, S. J . J . Org. Chem. 1978, 43, 1877.
(12) Unpublished results.

5876 Organometallics, Vol. 21, No. 26, 2002
Chopa et al.
Sch em e 2
employed in experiment 7 lead to better yields of the
monosubstituted compound 8.14
It should be noted that phenyl diethyl phosphate ester
(7)15 has been detected in low percentages (ca. 2-4%)
in the reactions carried out at short time (entries 4 and
5) and in the dark (entry 2). The presence of 7 is
probably due to the hydrogen abstraction reaction by
radical 7• from ammonia. Compound 9,16 detected in
experiments 1 and 9, probably was formed by the
reaction of 7 with 3 under photostimulation,8 as sketched
in eq 1.
Taking into account our results and with the aim of
increasing the yield of 1, we carried out reactions
between 4 and 3 under two different reaction conditions.
The results obtained indicate that while an increase in
the 3/4 ratio (5/1) did not produce a substantial incre-
ment in the yield of 1 (66%) (entry 9), a decrease in the
substrate concentration (1.78 mM, 4/3, 1/2.2 ratio) led
to a lower yield of 1 (50%) and to an increase in the
yield of compound 9 (19%) (entry 10). The latter result
suggests that, at lower concentration, the hydrogen
abstraction reaction by the radical 7• from ammonia
competes efficiently with the reaction between 7• and
anion 3.
Similar results have been obtained in the reaction of
tetraethyl-1,2-phenylene bisphosphate (5) with 3. Thus,
there was no reaction in the dark (entry 11), but under
irradiation (3.5 h) the disubstitution product 1 was
obtained in 67% yield (entry 12). The reaction carried
out at shorter time (1.5 h) led to a mixture of mono-
stannylated compound 8 (36%) and distannylated prod-
uct 1 (21%) (entry 13). While in experiment 13 the
presence of 7 (ca. 4%) was detected, in experiment 12
compound 9 was detected in about 3% yield.
respectively, rather than ET to the corresponding
substrate (k2 > k1, Scheme 2). The ET rates are probably
similar for eqs 2-4 shown in Scheme 2; therefore, it
follows that the intermediacy of a monosubstitution
product must be governed by the rate of fragmentation
of the intermediate radical anions. The different rates
of fragmentation of the 1,2-, 1,3-, and 1,4-trimethyl-
stannyl diethyl phosphate radical anions are probably
due to different spin densities at the 2-, 3-, and 4-carbon
atoms.11
All the experiments performed with 2,2′-bis(dieth-
ylphosphoxy)-1,1′-binaphthyl (6) are summarized in
Table 2.
We have found that there is no reaction between 6
and 3 in the dark (1 h). However, under irradiation in
the same time period the disubstitution product 2,2′-
bis(trimethylstannyl)-1,1′-binaphthyl (2)17 was obtained
in 66% yield together with 2-(trimethylstannyl)-1,1′-
binaphthyl (19)18 (14%) and 2-(trimethylstannyl)-2′-
(diethylphosphoxy)-1,1′-binaphthyl (20) (10%) (entries
1 and 2) (eq 5). These results clearly suggest an SRN1
mechanism.
Also, experiment 14 shows that an excess of anion 3
did not produce an increment in the percentage of 1
(65%). Taking into account our results, we are able to
say that 4 and 5 showed almost the same reaction
behavior toward anion 3 in liquid ammonia.
The results obtained in experiments 1 and 12 suggest
that 4 is more reactive than 5 toward 3 under the
reaction conditions studied. The difference in reactivity
is probably due to the fact that chloride is a better
leaving group compared with diethyl phosphate anion,
thus affecting the rate of formation of radical 7• (Scheme
1).
In previous works we have demonstrated that the
photostimulated reactions of tetraethyl-1,3-phenylene
(10) and 1,4-phenylene bisphosphates (11) as well as
4-chlorophenyl diethyl phosphate (12) with 3 led to the
corresponding distannylated products, i.e., 1,3-bis(tri-
methylstannyl)benzene (13) and 1,4-bis(trimethyl-
stannyl)benzene (14), in excellent yields (80-97%).8 In
these reactions, monostannylated compounds were not
detected even in reactions carried out at short time.
Disubstitution without accumulation of monosubsti-
tuted product may be attributed to preferential expul-
sion of the nucleofuge from the intermediate radical
anions 15•- and 16•- to form radicals 17• and 18•,
To determine if compound 20 is an intermediate, we
carried out a reaction at short time. In a photostimu-
lated reaction quenched after 15 min was detected 20
(14) To be used as the starting material in selective substitution
reactions (work in progress).
(15) Identified by GC/MS by comparison with an authentic sample
(17) Physical characteristics and NMR spectroscopic data are in
agreement with those reported in the literature.2
synthesized by the method of Kenner.21
(16) Identified by GC/MS by comparison with an authentic sample
synthesized by known procedures.8
(18) It has been detected and identified by GC/MS. MS (m/z, relative
intensity): 418 (1, M+), 403 (89, M - CH3), 373 (13), 252 (100).

Bis(trimethylstannyl)aryl Compounds
Organometallics, Vol. 21, No. 26, 2002 5877
Ta ble 2. Rea ction of
2,2′-Bis(d ieth ylp h osp h oxy)-1,1′-bin a p h th yl (6) w ith
Me3Sn Na in Liqu id Am m on ia
similar way as 4 and 5 do. Pathways similar to those
indicated in Scheme 1 could also be applied for the
reaction between 6 and 3.
entry 3/substratea conditions (time, h) 2 (%)b 19 (%)b 20 (%)b
1
2
3
4
5
6
7
8
9
2.2
2.2
2.2
2.2
2.2
2.2
2.2e
7
dark (1)
hν (1)
hν (0.25)
hν (4)
hν (7)
0
66
4
69
74
76
7
79
82
0
14
c
11
12
14
10
7
0
Con clu sion s
10
32d
7
2
c
49
<2
<2
We have developed a new approach for the synthesis
of bistannylated aromatic compounds useful as inter-
mediates in the preparation of bidentate Lewis acids.
We believe that this is a better and more practical
alternative to the existing methodologies of synthesis,
since this route proposed leads to the products with good
yields via a simple two-step sequence starting from
phenols. This route effects, for example, the transforma-
tion of 4 and 5 to 1 in an overall yield of 56% (85% in
the esterification step and 66% in the substitution step)
and the transformation of 6 to 2 in an overall yield of
63% (80% in the esterification step and 79% in the
substitution step). It should be noted that Kuivila could
not prepare 2 from the more readily accessible binaph-
thol by applying the Pd-catalyzed coupling of aryl
triflates with hexamethyldistannane, even after pro-
longed heating.2 Our method also has the advantage
that the formation of side products 9 and 19 by the
reduction of the radicals is kept to a minimun. It should
be pointed out that the separation of substrate 1 from
9 as well as that of 2 from 19 is very difficult. This fact
diminishes the yield of purified distannylated products.
The results obtained strongly suggest that the re-
placement of both nucleofuges in the starting materials
goes through an SRN1 mechanism and involves the
intermediacy of a monosubstitution product.
hν (10)
hν (0.5)
hν (7)
14
hν (7)
3
a
b
Substrate concentration 2.78 mM, except where stated. De-
termined by GC. c Small amount not quantified. Together with
d
21 (ca. 8%). e Substrate concentration 7.14 mM.
Sch em e 3
(32%) together with 2 (4%), 2-(diethylphosphoxy)-1,1′-
binaphthyl (21),19 (ca. 8%), traces of 19, and a substan-
tial amount of starting material (entry 3). This result
clearly indicates that 20 acts as an intermediate under
the reaction conditions studied. It should be noted that,
at longer reaction times, the yield of 2 increased at the
expense of 20, while the percentage of 19 remains
constant (entries 4-6). The amount of 21 detected in
the reaction carried out at short time may result from
the reduction of radical 21•. The presence of compound
19 in all the photostimulated experiments is probably
due to the reaction of 21 with 3 under photostimulation
as sketched in step 2 of Scheme 3.
Keeping in mind the results obtained in the reaction
between 4 and 3 at large substrate concentration and
aiming to increase the yield of compound 20,14 we
carried out experiment 7. Under these reaction condi-
tions compound 20 was formed in 49% yield together
with compounds 2 (7%) and 19 (10%).
On the other hand, to improve the yields of disubsti-
tution product 2, we carried out two reactions employing
an excess of anion 3, as indicated in experiments 8 and
9. Comparison of experiments 5, 8, and 9 suggests that
an excess of 3 produces a considerable decrease of 19
together with a slight improvement in the amount of 2.
These results could be explained by considering that
once the radical 2-(diethylphosphoxy)-1,1′-binaphthyl
(21•) is formed, two competitive reactions could take
place (Scheme 3). Radical 21• either reacts with 3,
leading at last to the disubstitution product 2 (step 1),
or removes a hydrogen from ammonia, leading to
compound 21 (step 2). Step 1 involves a bimolecular
reaction whose rate is increased when the reaction is
carried out employing an excess of 3.
Exp er im en ta l Section
Gen er a l P r oced u r es. Irradiation was conducted in a
reactor made of Pyrex, equipped with four 250 W UV lamps
emitting maximally at 350 nm, that was water-cooled. The
reagents were commercially available. 2,2′-Dihydroxy-1,1′-
binaphthyl was prepared according to published procedures.20
Aryl diethyl phosphate esters were prepared by the method
of Kenner21 and characterized by IR and proton NMR spec-
troscopy.22 For each compound, the product from at least one
reaction was purified and isolated by column chromatography
on silica gel, and the IR and NMR spectra as well as MS
measurements were determined. To carry out the reactions
in the dark, the reaction flask was wrapped with aluminum
foil.
P h otostim u la ted Rea ction of 2-Ch lor op h en yl Dieth yl
P h osp h a te (4) w ith Me3Sn Na (3). The reactions were
performed by following the same procedure in all cases.
Sodium-dried ammonia (150 mL) was condensed into a 250
mL two-necked, round-bottomed Pyrex flask equipped with a
cold finger condenser, a nitrogen inlet, and a magnetic stirrer.
Me3SnCl (0.219 g, 1.1 mmol) was dissolved in the ammonia,
and Na metal (0.058 g, 2.53 mg atom) was added until a blue
color persisted for at least 5 min. When the blue color
disappeared, 4 (0.132 g, 0.50 mmol) was added and then the
mixture was irradiated with stirring, for 1.5 h. The reaction
was quenched by adding an aqueous saturated solution of
(20) Vogel’s Textbook of Practical Organic Chemistry, 4th ed.;
Longman: New York, 1978; p 613.
(21) Kenner, G. W.; Williams, N. R. J . Chem. Soc. 1955, 522.
(22) The IR spectra of the esters present characteristic absorptions
at 1030, 1155-1164, 1183-1214, and 1265-1274 cm-1. The 1H NMR
All of the aforementioned results constitute evidence
that 6 reacts with 3 through an SRN1 mechanism in a
spectra present a double triplet at 1.35-1.51 ppm (3J H,H ) 7.0-7.2
Hz, J H,P ) 1.1 Hz) and a double quartet at 4.25-4.45 ppm (3J H,H
)
4
3
(19) It has been detected and identified by GC/MS. MS (m/z, relative
intensity): 406 (100, M+), 378 (9, M - 28), 349 (11), 252 (79).
7.0-7.2 Hz, J H,P ) 5.8-6.2 Hz) as well as the absorption due to the
aryl groups.

5878 Organometallics, Vol. 21, No. 26, 2002
Chopa et al.
ammonium chloride, and ammonia was allowed to evaporate.
The residue was treated with water and then extracted with
ether. Ether extracts were washed with an aqueous saturated
solution of NaCl and dried over MgSO4. The mixture composi-
tion was identified by GC/MS. Product 1 was isolated by TLC
chromatography on silica gel (0.111 g, 0.30 mmol, 60%), and
its spectroscopic data agreed with those reported in the
literature.1
out in experiment 3 (Table 2). 119Sn{1H} NMR (CDCl3):
δ
-27.5. 31P NMR (CDCl3) δ 43.5. 1H NMR (CDCl3): δ 0.0 (s,
3
2J (H,Sn) ) 55.3/52.8 Hz, 9 H, SnMe3); 1.1 (m, J (H,H) ) 7.1
Hz, 4J (H,P) ) 1.1 Hz, 3H, CH3); 1.26 (m, 3J (H,H) ) 7.1 Hz,
4J (H,P) ) 1.0 Hz, 3H, CH3); 3.66 (m, 3J (H,H) ) 7.1 Hz, 3J (H,P)
3
3
) 6.0 Hz, 2H, CH2); 3.83 (m, J (H,H) ) 7.1 Hz, J (H,P) ) 5.9
Hz, 2H, CH2); 7.44-7.56 (m, 2H, Ph); 7.66-7.71 (m, 2H, Ph);
7.97-8.01 (m, 2H, Ph); 8.11-8.25 (m, 4H, Ph). 13C{1H} NMR
(CDCl3): δ -8.6 (1J (C,Sn) ) 350.4/333.9 Hz), SnCH3; 15.9
(3J (C,P) ) 7.0 Hz, CH3); 16.1 (3J (C,P) ) 6.5 Hz, CH3); 64.4
(2J (C,P) ) 6.5 Hz, CH2); 64.6 (2J (C,P) ) 6.5 Hz, CH2); 119.9
(4J (C,P) ) 2 Hz, CHaryl); 125.8 (CHaryl); 126.4 (4J (C,P) ) 2 Hz,
CHaryl); 126.8 (CHaryl); 127.2 (CHaryl); 127.31 (CHaryl); 128.1
(CHaryl); 128.4 (CHaryl); 129.0 (3J (C,P) ) 8 Hz, Caryl); 130.2
(CHaryl); 131.4 (Caryl); 132.7 (2J (C,Sn) ) 38 Hz, CHaryl); 133.2
(Caryl); 133.9 (4J (C,Sn) ) 8 Hz, Caryl); 134.8 (Caryl); 141.1
(3J (C,Sn) ) 29 Hz, Caryl); 143.3 (Caryl); 147.0 (2J (C,P) ) 6 Hz,
(2-Tr im et h ylst a n n yl)p h en yl Diet h yl P h osp h a t e (8).
Separation of compound 8 from 1 and 4 by careful column
chromatography (eluent hexane/ethyl acetate (50/50)) was
made feasible from the reaction between 4 and 3 (1/1 ratio)
carried out in experiment 6 (Table 1). 119Sn{1H} NMR
(CDCl3): δ 44.6. 31P NMR (CDCl3): δ -28.7. 1H NMR
2
(CDCl3): δ 0.26 (s, J (H,Sn) ) 54.0 Hz, 9 H, SnMe3); 1.26 (m,
3J (H,H) ) 7.0 Hz, 4J (H,P) ) 1.0 Hz, 6 H, CH3); 4.12 (m, 3J (H,H)
3
) 7.0 Hz, J (H,P) ) 6.0 Hz, 4 H, CH2); 7.06 (m, 1 H, Ph); 7.23
(m, 1 H, Ph); 7.35 (m, 2 H, Ph). 13C{1H} NMR (CDCl3): δ -8.5
(1J (C,Sn) ) 348/364 Hz, SnCH3); 16.5 (3J (C,P) ) 6.5 Hz, CH3);
64.8 (2J (C,P) ) 6.0 Hz, CH2); 118.1 (3J (C,Sn) ) 16.0 Hz, 4J (C,P)
) 2.0 Hz, Caryl); 125.0 (2J (C,Sn) ) 40 Hz, Caryl); 130.5 (Caryl);
132.9 (2J (C,P) ) 11.2 Hz, Caryl); 137.2 (3J (C,Sn) ) 23 Hz, Caryl);
156.5 (3J (C,P) ) 6.5 Hz, Caryl). MS (m/z, relative intensity):
394 (2, M+), 379 (100, M - CH3), 351 (17), 337 (4), 323 (82),
307 (39), 293 (34).
C
aryl). MS (m/z, relative intensity): 570 (3, M+), 555 (100, M -
CH3), 525 (5), 495 (4), 419 (35), 389 (63).
Ack n ow led gm en t. This work was partially sup-
ported by the Consejo Nacional de Investigaciones
Cient´ıficas y Te´cnicas (CONICET) and the Universidad
Nacional del Sur, Bah´ıa Blanca, Argentina. Special
thanks go to Dr. A. E. Zu´n˜iga for obtaining the mass
spectra. CONICET is thanked for a research fellowship
to G.F.S.
2-(Tr im eth ylstan n yl)-2′-(dieth ylph osph oxy)-1,1′-bin aph -
th yl (20). Separation of compound 20 from 2 and 6 by careful
column chromatography (eluent hexane/ethyl acetate (50/50))
was made feasible from the reaction between 6 and 3 carried
OM020622O