Diastereoselective Synthesis and Stereochemical Research of Optically Pure Telluronium Salts

Article abstract of DOI:10.1021/jo9803131

The synthesis of optically pure telluronium salts 4a-i, using the 2-exo-hydroxy-10-bornyl group as a chiral ligand, has been achieved in high yield and selectivity by the reaction of chiral alkoxytelluranes 3a-i with organolithium and Grignard reagents. Both diastereoisomers of ethyl(2-exo-hydroxy-10-bornyl)methyltelluronium chloride (4a,b) and butyl(2-exo-hydroxy-10-bornyl)-methyltelluronium chloride (4c,d) have been synthesized in optically pure form in high yield and with excellent diastereoselectivity. The method has been used for the asymmetric synthesis of chiral benzyl- and allyltelluronium salts 5a-h. Structures of these salts have been confirmed by X-ray analyses of 4a and 4b, which indicated that all of the salts have their pyramidal geometrical structures around the tellurium atom. The thermal and optical stability and the possible mechanisms of the reaction are also discussed.

Full text of DOI:10.1021/jo9803131

J . Org. Chem. 1998, 63, 5423-5429
5423
Dia ster eoselective Syn th esis a n d Ster eoch em ica l Resea r ch of
Op tica lly P u r e Tellu r on iu m Sa lts
J ian Zhang, Shinichi Saito,*,† and Toru Koizumi*,‡
Faculty of Pharmaceutical Sciences, Toyama Medical & Pharmaceutical University, 2630 Sugitani,
Toyama 930-0194, J apan
Received February 19, 1998
The synthesis of optically pure telluronium salts 4a -i, using the 2-exo-hydroxy-10-bornyl group
as a chiral ligand, has been achieved in high yield and selectivity by the reaction of chiral
alkoxytelluranes 3a -i with organolithium and Grignard reagents. Both diastereoisomers of ethyl-
(2-exo-hydroxy-10-bornyl)methyltelluronium chloride (4a ,b) and butyl(2-exo-hydroxy-10-bornyl)-
methyltelluronium chloride (4c,d ) have been synthesized in optically pure form in high yield and
with excellent diastereoselectivity. The method has been used for the asymmetric synthesis of
chiral benzyl- and allyltelluronium salts 5a -h . Structures of these salts have been confirmed by
X-ray analyses of 4a and 4b, which indicated that all of the salts have their pyramidal geometrical
structures around the tellurium atom. The thermal and optical stability and the possible
mechanisms of the reaction are also discussed.
Organochalcogenonium compounds such as chalco-
genoxides, chalcogenonium imides, chalcogenonium ylides,
chalcogenonium salts, and chalcogenuranes may become
chiral when different substituents are attached to the
chalcogen atom (Figure 1). Although many chiral organo-
sulfur compounds have been prepared and the stereo-
chemistry has been studied extensively,1,2 the synthesis
and stereochemistry of chiral organotellurium compounds
have been studied to a lesser extent.3,4 Kamigata et al.
have reported recently on the first isolation of optically
pure dialkylaryltelluronium salts 1 with defined stereo-
chemistry by optical resolution.4a-h In contrast to the
previous reports,4c,d they found that the telluronium salts
were optically stable compounds and did not racemize
easily.4a,b However, the number of chiral tellurium
compounds with defined stereochemistry is still small,
and further study is needed to develop synthetic methods
and to establish the stereochemistry and optical stability
of chiral organotellurium compounds.
F igu r e 1.
telluronium salts by the reaction of chiral halooxatellu-
ranes with alkyllithium or Grignard reagents.5 The
stereochemical study and possible mechanisms of the
reaction will also be discussed.
In this paper, we describe the details of the first
asymmetric synthesis and the structure of optically pure
Resu lts a n d Discu ssion
† Present address: Institute for Chemical Reaction Sciences, Tohoku
University, Sendai, 980-8578, J apan.
‡ Deceased J anuary 12, 1998.
Syn th esis of Op tica lly P u r e Tellu r on iu m Sa lts.
Chiral chlorooxatelluranes 3a -e were synthesized by the
treatment of tellurides 2a -e with t-BuOCl. Bromotel-
luranes 3f-i were obtained by halogen exchange reaction
of chlorotelluranes with NaBr (Scheme 1).6 Nucleophilic
reaction of methylbromooxatellurane 3f with 1.2 equiv
of ethylmagnesium bromide in CH2Cl2 followed by work-
up with NH4Cl (aq) gave ethyl(2-exo-hydroxy-10-bornyl)-
(1) Oae, S. Organic Chemistry of Sulfur; Kagakudoujin: Kyoto, 1982.
(2) For the synthesis of optically active sulfonium and selenonium
salts: (a) Andersen, K. K.; Caret, R. L.; Karup-Nielsen, I. J . Am. Chem.
Soc., 1974, 96, 8026-8032. (b) Andersen, K. K.; Caret, R. L.; Ladd, D.
L. J . Org. Chem. 1976, 41, 3096-3100. (c) Kobayashi, M.; Koyabu, K.;
Shimizu, T.; Umemura, K.; Matsuyama, H. Chem. Lett. 1986, 2117-
2120. (d) Umemura, K.; Matsuyama, H.; Watanabe, N.; Kamigata, N.
J . Org. Chem. 1989, 54, 2374-2383. (e) Umemura, K.; Matsuyama,
H.; Kamigata, N. Bull. Chem. Soc. J pn. 1990, 63, 2593-2600. (f) Green,
T. K.; Whetstine, J . R.; Son, E. Tetrahedron: Asymmetry 1997, 8, 3175-
3181.
(3) Recent reviews on the chemistry of tellurium compounds: (a)
Engman, L. Acc. Chem. Res. 1985, 18, 274. (b) Petragnani, N.;
Comasseto, J . V. Synthesis 1986, 1-30; 1991, 793-817, 897-919. (c)
Petragnani, N. Tellurium in Organic Synthesis; Academic Press:
London, 1994. (d) Comasseto, J . V.; Lin, L. W.; Petragnani, N.; Stefani,
H. A. Synthesis 1997, 373-403. (e) Shimizu, T.; Kamigata, N. J . Synth.
Org. Chem. J pn. 1997, 55, 35-43.
(4) (a) Shimizu, T.; Urakubo, T.; Kamigata, N. Chem. Lett. 1996,
297-298. (b) Shimizu, T.; Urakubo, T.; Kamigata, N. J . Org. Chem.
1996, 61, 8032-8038. (c) Lowry, T. M.; Gilbert, F. L. J . Chem. Soc.
1929, 2867-2876. (d) Holliman, F. G.; Mann, F. G. J . Chem. Soc. 1945,
37-44.
(5) A part of this work has been reported as a communication:
Zhang, J .; Saito, S.; Koizumi, T. Tetrahedron: Asymmetry 1997, 8,
3357-3361. The structure of 5b was also determined by X-ray
crystallographic analysis.
(6) (a) Takahashi, T.; Kurose, N.; Kawanami, S.; Arai, Y.; Koizumi,
T.; Shiro, M. J . Org. Chem. 1994, 59, 3262-3264. (b) Kurose, N.;
Takahashi, T.; Koizumi, T. J . Org. Chem. 1996, 61, 2932-2933. (c)
Zhang, J .; Takahashi, T.; Koizumi, T. Heterocycles 1997, 44, 325-339.
(d) Takahashi, T.; Zhang, J .; Kurose, N.; Takahashi S.; Koizumi, T.
Shiro, M. Tetrahedron: Asymmetry 1996, 7, 2797-2800. (e) Takahashi,
T.; Kurose, N.; Kawanami, S.; Nojiro, A.; Arai, Y.; Koizumi, T.; Shiro,
M. Chem. Lett. 1995, 379-380.
S0022-3263(98)00313-2 CCC: $15.00 © 1998 American Chemical Society
Published on Web 07/17/1998

5424 J . Org. Chem., Vol. 63, No. 16, 1998
Zhang et al.
Sch em e 1
Sch em e 2
F igu r e 2.
Ta ble 1. Syn th esis of Tellu r on iu m Sa lts 4a -i
R2Li or
R2MgX
yield
(%)
entry telluranes
tellurium salts
1
2
3
4
5
6
7
8
9
3f
EtMgBr
MeLi
4a , R1 ) Me, R2 ) Et
4b, R1 ) Et, R2 ) Me
87
79
82
92
97
90
79
97
76
3b
3a
3c
3b
3h
3e
3i
n-BuMgCl 4c, R1 ) Me, R2 ) n-Bu
methyltelluronium chloride (4a ) in 87% yield as a single
diastereomer. Reaction of ethylchlorooxatellurane 3b
with methyllithium under the similar conditions gave
ethyl(2-exo-hydroxy-10-bornyl)methyltelluronium chlo-
ride (4b) in 79% yield also as a single diastereomer
(Scheme 2). No telluronium salts epimeric at tellurium
were detected in these reactions. In the 1H NMR
spectrum of 4a , an absorption for the methyl group bound
to the tellurium atom was observed at 2.35 ppm, and an
absorption for the methylene proton was observed at 2.75
and 2.83 ppm. In contrast, the corresponding absorption
appeared at 2.32, 2.59, and 2.95 ppm in the 1H NMR
spectrum of 4b. In the 125Te NMR spectrum, an absorp-
tion was observed at 498 ppm for 4a and at 488 ppm for
4b. Obviously, their spectroscopic characteristics indi-
cate that the two telluronium salts are quite different
from each other.
The structures of the salt 4a and 4b were finally
determined by X-ray crystallographic analyses as shown
in Figure 2. Telluronium salt 4a has a pyramidal
geometrical structure with an S absolute configuration
at the telluronium center (Figure 2). The bond distances
of Te-C [2.16(2) Å, 2.083(8) Å, 2.139(7) Å] are of normal
values, and the average value of C-Te-C angles of 94.2-
(7)° is comparable with that of the reported ethylmeth-
ylphenyltelluronium salts.4a,b The X-ray crystallographic
analysis of telluronium salt 4b (Figure 2) proved that 4b
is a diastereoisomer of 4a . Thus, we have succeeded in
the stereoselective synthesis of both diastereoisomers of
ethyl(2-exo-hydroxy-10-bornyl)methyltelluronium salts.
At the same time, we confirmed that both diastereomers
of the telluronium salts are optically stable compounds
and they do not isomerize during workup.
MeLi
4d , R1 ) n-Bu, R2 ) Me
n-BuMgCl 4e, R1 ) Et, R2 ) n-Bu
EtMgBr
MeLi
EtMgBr
4f, R1 ) n-Bu, R2 ) Et
4g, R1 ) C6H5, R2 ) Me
4h , R1 ) C6H5, R2 ) Et
3e
n-BuMgCl 4i, R1 ) C6H5, R2 ) n-Bu
methyltelluronium chloride (4c, d ) were also obtained by
the reaction of butyltellurane with methyllithium or of
methyltellurane with butylmagnesium chloride (Table 1,
entries 3 and 4). The reactions of other halotelluranes
also proceeded smoothly to afford chiral salts in high yield
and with excellent diastereoselectivity. The reactivity of
phenyltellurane was similar to that of alkyltelluranes,
and reactions of phenyltellurane 3e and 3i with meth-
yllithium or Grignard reagents gave phenyltelluronium
salts 4g-i in good yield and as sole products (Table 1,
entries 7-9). The salts epimeric at tellurium atom were
not detected in these reactions. Stereochemistry of these
telluronium salts can be assigned as depicted in Scheme
2 by analogy with that of 4a and 4b.
The scope of the new method was extended to include
the more synthetically attractive benzyl- and allyltellu-
ronium salts. Nucleophilic reaction of a chiral chlorooxa-
tellurane 3a with 1.2 equiv of benzylmagnesium chloride
in CH2Cl2 for ca. 2 h followed by usual workup gave
chlorotelluronium salt 5a (95% yield) as a single dia-
stereomer.7 The same reaction of benzylmagnesium
(7) The selectivity of the reaction of methyltellurane with benzyl-
magnesium chloride was found to be dependent on the amount of the
Grignard reagent. When the methyltellurane was treated with 1.1
equiv of benzylmagnesium chloride, salt 5b was obtained as the sole
product, whereas an excess amount of the Grignard reagent gave the
salt in low diastereoselectivity. This observation was reasonably
explained in terms of the formation of the tetracoordinated tellurium
complex under the basic conditions. Treatment of optically pure
benzyltelluronium salt 5b with excess benzylmagnesium chloride gave
also isomerization at the tellurium atom to yield an approximately 1:1
mixture of diastereoisomers.
To study the generality of this reaction, we performed
the reactions of various halooxatelluranes with alkyl-
lithium and Grignard reagents as shown in Table 1. The
two diastereomers of butyl(2-exo-hydroxy-10-bornyl)-

Synthesis of Optically Pure Telluronium Salts
J . Org. Chem., Vol. 63, No. 16, 1998 5425
Ta ble 2. Syn th esis of Ben zyl- a n d Allyltellu r on iu m
Another possible pathway might involve an alkyloxo-
tellurane, which is formed by the substitution of the
halogen atom with the alkyl group, as an intermediate.
However, it is difficult to explain the stereochemical
results observed in the reaction, since it is likely that the
pentacoordinated intermediate will be converted to a
telluronium salt with different stereochemistry. There-
fore, we consider the former pathway to be more reason-
able. Further study is necessary to elucidate the mech-
anism of this reaction.10
Sa lts 5a -h
yield
entry
tellurane
telluronium salt
(%)
Con clu sion
1
2
3
4
5
6
7
8
3a
3b
3c
3d
3e
3f
5a , R1 ) Me, R2 ) Ph
95
81
78
67
73
94
60
90
5b, R1 ) Et, R2 ) Ph
5c, R1 ) n-Bu, R2 ) Ph
5d , R1 ) n-C6H13, R2 ) Ph
5e, R1 ) C6H5, R2 ) Ph
5f, R ) Me, R2 ) CH2dCH
5g, R ) Et, R2 ) CH2dCH
5h , R ) C6H5, R2 ) CH2dCH
In conclusion, we developed a facile method for the
stereoselective synthesis of optically pure telluronium
salts using the 2-exo-hydroxy-10-bornyl group as a chiral
ligand by the reaction of chiral alkoxytelluranes with
alkyllithium or Grignard reagents. Optically pure ben-
zyl- and allyltelluronium salts have also been synthe-
sized. The optical stability of trialkyltelluronium salts
was confirmed. We proposed a speculative mechanism
of this reaction, which accounts for the observed stere-
ochemistry.
3g
3i
Sch em e 3
Exp er im en ta l Section
Gen er a l Meth od s. Common experimental procedures and
instrumentation have been described previously.6c Spectro-
scopic measurements were carried out with the following
instruments: 125Te NMR, Varian Unity 500 (157.9 MHz) for
solutions in CDCl3 with Ph2Te2 (0.5 M in CH2Cl2, 422 ppm) as
an external standard. Coupling constants (J ) are given in Hz.
The ditelluride was synthesized according to the procedure
reported in the literature.11
(1S)-10-Iod o-2-exo-bor n eol. To a solution of NaBH4 (800
mg, 22.36 mmol) in EtOH (30 mL) was added a solution of
(1S)-10-iodocamphor12 (6.0 g, 22.86 mmol) in EtOH (60 mL)
under N2 atmosphere at 0 °C. The mixture was stirred at 0
°C to rt for 1 night. The reaction was quenched with saturated
NH4Cl (ca.10 mL) at rt followed by concentration of the solvent
to one-fourth of its original volume. Then, the mixture was
extracted with CH2Cl2 (100 mL × 2). The organic layer was
washed with H2O (15 mL × 2) followed by brine (15 mL × 1)
and dried over MgSO4. Removal of the solvent under reduced
pressure gave the crude product, which was purified by column
chromatography (hexane/EtOAc 19:1) to give the product (4.89
g, 76%) as a semisolid: [R]26D -31.22° (c 2.02, CHCl3); IR (neat)
chloride with telluranes 3b-e was also performed and
afforded telluronium salts 5b-e as single diastereomers
in good yield as shown in Table 2.5 Reaction of bromo-
telluranes 3f,g,i with allylmagnesium bromide gave allyl
telluronium salts 5f-h in moderate to good yields as
single diastereomers after usual workup (Table 2).5
These salts are precursors of the optically active tellu-
ronium ylides, which will be a useful building block in
organic synthesis.
We found that the telluronium salts obtained in this
study did not isomerize after the salts were allowed to
stand at room temperature for several weeks. A solution
(CHCl3 or MeOH) of 4a or 4b was heated to reflux for 5
h to give only the starting materials recovered in almost
quantitative yield. Thus, these trialkyltelluronium salts,
as well as dialkylaryltelluronium salts,4a,b are highly
stable toward pyramidal inversion.
1
3478, 2953, 1306, 1188, 1070, 1019 cm-1; H NMR δ 0.87 (s,
3H), 1.06 (s, 3H), 1.22-1.49 (m, 2H), 1.50-1.86 (m, 4H), 2.00-
2.09 (m, 2H), 3.18 (d, J ) 9.3, 1H), 3.45 (d, J ) 9.3, 1H), 3.78
(dd, J ) 3.9, 7.7, 1H);13C NMR δ 11.5, 20.4, 21.1, 26.7, 33.3,
39.5, 47.2, 47.8, 52.8, 78.4; MS m/z 280, 153; HRMS calcd for
C
10H17IO 280.0326, found 280.0276.
(8) For nucleophilic reaction of halosulfuranes through a hexacoor-
dinated transition state, see: (a) Balthazor, T. M.; Martin, J . C. J .
Am. Chem. Soc. 1975, 97, 5634-5635. (b) Martin, J . C.; Balthazor, T.
M. J . Am. Chem. Soc. 1977, 99, 152-162.
(9) We have suggested to use “retention” and “inversion” to describe
the stereochemistry of the transformation of halooxachalcogenurane
to chalcogenium compound; see ref 5.
(10) Andersen et al. have reported the synthesis of sulfonium salts
by the reaction of Grignard reagents and alkylcadmium reagents with
(alkyloxy)sulfonium salts derived by O-alkylation of sulfoxides. They
have tried to prepare the optically active sulfonium salts via this
reaction starting from chiral sulfoxides, but unfortunately, they have
failed to get the sulfonium salts with high ee value, and the racemic
sulfonium salts were often obtained because of the racemization of the
products or because of other undentified reasons, according to the
authors’ explanation: see ref 2a,b.
P ossible Mech a n ism s
Although the detailed stereochemical process of the
reaction is not clear at the present time, the reaction may
proceed through the pathway shown in Scheme 3. Initial
chelation of Grignard reagents with the oxygen atom of
the bornyl group induced the attack of the carbanion from
the direction shown in Scheme 3. The coordinated metal
induced the cleavage of the Te-O bond followed by the
dissociation of the Te-Cl bond to afford telluronium salts
with the observed configuration at the tellurium atom
in high diastereoselectivity.5,8,9
(11) Ferreira, J . T. B.; de Oliveira, A. R. M.; Comasseto, J . V. Synth.
Commun. 1989, 239-244.
(12) Oae, S.; Togo, H. Synthesis 1981, 371-373.

5426 J . Org. Chem., Vol. 63, No. 16, 1998
Zhang et al.
(1S)-10-(Meth yltellu r en yl)-2-exo-bor n eol (2a ). To a so-
lution of dimethyl ditelluride (400 mg, 1.40 mmol) and (1S)-
10-iodo-2-exo-borneol (775 mg, 2.77 mmol) in absolute EtOH
(15 mL) was added NaBH4 (140 mg, 3.68 mmol) under N2
atmosphere at -10 °C, and the mixture was stirred until the
red color of the ditelluride disappeared (ca. 10 min). Then the
whole solution was heated under reflux for 20 min. The
reaction was quenched with H2O (8 mL) at rt and the mixture
was extracted with CH2Cl2 (40 mL × 2). The organic layer
was washed with H2O (6 mL × 2) followed by brine (6 mL ×
1) and dried over MgSO4. Removal of the solvent under
reduced pressure gave the crude product, which was purified
by column chromatography (hexane/EtOAc 40:1) to give 2a
20.1, 20.8, 22.8, 27.1, 31.3, 31.9, 32.4, 33.6, 39.5, 45.6, 47.5,
53.0, 78.7; MS m/z 368 (M+, 130Te), 366 (M+,128Te), 364 (M+,
126Te), 214, 212, 135, 109, 93, 79, 67, 55; HRMS calcd for
C
16H30OTe 368.1364 (M+, 130Te), 366.1351(M+, 128Te), found
368.1292, 366.1288.
Gen er a l P r oced u r e for th e Syn th esis of Ha looxa tel-
lu r a n es 3a -i. To a solution of tellurides (1 mmol) in dry CH2-
Cl2 (8 mL) was added t-BuOCl (0.13 mL, 1.05 mmol) under a
N2 atmosphere at 0 °C, and the mixture was stirred at 0 °C
for 20 min. Removal of the solvent under reduced pressure
gave the crude product as a white solid. Purification of the
residue by recrystallization from hexane and CH2Cl2 afforded
chlorooxatelluranes 3a -e as colorless crystals. Bromooxatel-
luranes 3f-i were obtained by treatment of the corresponding
chlorooxatelluranes with NaBr (3 equiv) in CH3CN at rt
overnight.
(570 mg, 70%) as a red oil: [R]26 -30.26° (c 1.70, CHCl3); IR
D
(neat) 3467, 2949, 1454, 1386, 1070, 1018, 865 cm-1; 1H NMR
δ 0.78 (s, 3H), 0.98 (s, 3H), 1.0-1.15 (m, 2H), 1.42-1.6 (m,
1H), 1.6-1.9 (m, 5H), 1.86 (s, 3H), 2.71 (d, J ) 11.0, 1H), 2.75
(d, J ) 10.5, 1H), 3.72 (dd, J ) 3.9, 7.7, 1H); 13C NMR δ -21.8,
4.9, 20.1, 20.8, 27.1, 33.5, 39.6, 45.6, 47.5, 53.2, 78.7; 125Te NMR
δ 628; MS m/z 298 (M+, 130Te), 296 (M+,128Te), 294 (M+, 126Te),
135, 109, 93, 81, 67, 55; HRMS calcd for C11H20OTe 298.0582
(M+, 130Te), 296.0569 (M+, 128Te), found 298.0505, 296.0471.
(1S)-10-(Eth yltellu r en yl)-2-exo-bor n eol (2b). To a solu-
tion of diethyl ditelluride (1.0 g, 3.18 mmol) and (1S)-10-iodo-
2-exo-borneol (1.8 mg, 6.38 mmol) in absolute EtOH (15 mL)
was added NaBH4 (480 mg, 12.63 mmol) under N2 atmosphere
at 0 °C, and the mixture was stirred until the red color of the
ditelluride disappeared (ca. 10 min). Then the solution was
heated under reflux for 20 min. The reaction was quenched
with H2O (10 mL) at rt, and the mixture was extracted with
CH2Cl2 (75 mL × 2). The organic layer was washed with H2O
(10 mL × 2) followed by brine (10 mL × 1) and dried over
MgSO4. Removal of the solvent under reduced pressure gave
the crude product, which was purified by column chromatog-
raphy (hexane/EtOAc 40:1) to give 2b (1.33 g, 67%) as a red
oil: [R]26D -33.95° (c 2.00, CHCl3); IR (neat) 3390, 2950, 1368,
[2R-(2r,3a r,6r,7a â)]-2-Ch lor o-2,2,5,6,7,7a -h exa h yd r o-
8,8-d im eth yl-2-m eth yl-4H-3a ,6-m eth a n o-3H-1,2-ben zoxa -
tellu r ole (3a ): [R]26 +85.22° (c 1.00, CHCl3); IR (KBr) 2942,
D
1455, 1386, 1047, 989, 868 cm-1; 1H NMR δ 0.91 (s, 3H), 1.04
(s, 3H), 1.2-1.27 (m, 2H), 1.55-2.0 (m, 5H), 2.75 (s, 3H), 3.4
(d, J ) 13.2, 1H), 3.59 (d, J ) 13.2, 1H),4.19 (dd, J ) 3.3, 7.1,
1H); 13C NMR δ 20.4, 20.5, 22.2, 26.9, 31.7, 40,8, 41.9, 45.6,
46.6, 55.6, 93.7; MS m/z 334 (M+, 130Te, 37Cl), 332 (M+, 130Te,
35Cl/128Te, 37Cl), 330 (M+, 128Te, 35Cl/126Te, 37Cl), 328 (M+, 126Te,
35Cl), 297, 295, 293, 180, 178, 176, 107, 93, 81, 67, 55. Anal.
Calcd for C11H19ClOTe: C, 40.00; H, 5.80. Found: C, 40.05;
H, 5.69.
[2R-(2r,3a r,6r,7a â)]-2-Ch lor o-2,2,5,6,7,7a -h exa h yd r o-
8,8-d im et h yl-2-et h yl-4H -3a ,6-m et h a n o-3H -1,2-b en zoxa -
tellu r ole (3b): mp 130-132 °C (colorless prisms); [R]26D +93.1
° (c 1.36, CHCl3); IR (KBr) 3008, 2954, 2881, 1456, 1388, 1114,
1
1068, 1048, 1014 cm-1; H NMR δ 0.92 (s, 3H), 1.06 (s, 3H),
1.19 (dd, J ) 9.9, 18.7, 2H), 1.63-1.95 (m, 5H), 1.71 (t, J )
7.7, 3H), 3.13-3.30 (m, 2H), 3.35 (d, J ) 13.5, 1H), 3.50 (d, J
) 13.5, 1H), 4.15 (dd, J ) 3.3, 7.7, 1H); 13C NMR δ 10.9, 20.5,
20.7, 26.8, 31.4, 35.0, 41.9, 44.0, 45.6, 46.7, 55.4, 93.9; 125Te
NMR δ 1852; MS m/z 348 (M+, 130Te, 37Cl), 346 (M+, 130Te, 35Cl/
128Te, 37Cl), 344 (M+, 128Te, 35Cl/126Te, 37Cl), 342 (M+, 126Te, 35Cl).
Anal. Calcd for C12H21ClOTe: C, 41.86; H, 6.15. Found: C,
41.71; H, 6.15.
1071, 1019, 866 cm-1 1H NMR δ 0.85 (s, 3H), 1.06 (s, 3H),
;
1.0-1.2 (m, 2H), 1.61 (t, J ) 7.7, 3H), 1.40-1.85 (m, 5H), 2.66
(q, J ) 7.7, 2H), 2.22-2.70 (br, 1H), 2.78 (d, J ) 10.4, 1H),
2.84 (d, J ) 10.4, 1H), 3.77 (dd, J ) 3.8, 7.7, 1H); 13C NMR δ
-4.7, 3.5, 18.0, 20.2, 20.9, 26.9, 27.2, 33.7, 39.6, 45.7, 53.0,
78.7; 125Te NMR δ 812; MS m/z 312 (M+, 130Te), 310 (M+, 128Te),
[2R-(2r,3a r,6r,7a â)]-2-Ch lor o-2,2,5,6,7,7a -h exa h yd r o-
8,8-d im et h yl-2-b u t yl-4H -3a ,6-m et h a n o-3H -1,2-b en zoxa -
tellu r ole (3c): mp 164-165 °C; [R]26D +88.12° (c 1.22, CHCl3);
308 (M+, 126Te), 135, 107, 93, 67, 55; HRMS calcd for C12H22
OTe 312.0740 (M+, 130Te), found 312.0748.
-
1
(1S)-10-(Bu tyltellu r en yl)-2-exo-bor n eol (2c). The pro-
cedure described in the preparation of 2b was generally
followed to prepare 2c from (1S)-10-iodo-2-exo-borneol and
IR (neat) 2959, 1452, 1388, 1354, 1048, 584 cm-1; H NMR δ
0.91 (s, 3H), 0.99 (t, J ) 7.1, 3H), 1.05 (s, 3H), 1.11-1.3 (m,
2H), 1.42-1.61 (m, 3H), 1.68-1.80 (m, 1H), 1.8-2.11 (m, 3H),
3.22 (t, J ) 7.1, 2H), 3.35 (d, J ) 13.2, 1H), 3.50 (d, J ) 13.2,
1H), 4.13 (dd, J ) 3.3, 7.7, 1H); 13C NMR δ 13.8, 20.5, 20.7,
24.7, 27.0, 28.0, 31.7, 39.2, 42.2, 45.8, 46.8, 55.6, 93.9 (a signal
will be overlapped with the signal of CDCl3); 125Te NMR δ
1838; MS m/z 376 (M+, 130Te, 37Cl), 374 (M+, 130Te, 35Cl/128Te,
37Cl), 372 (M+, 128Te, 35Cl/126Te, 37Cl), 370 (M+, 126Te, 35Cl) 339,
ditelluride. 2c: yield 40%; red oil; [R]26 -28.00° (c 2.05,
D
CHCl3); IR (neat) 3468, 2952, 1454, 1386, 1071, 1018, 864 cm-1
;
1H NMR δ 0.83 (s, 3H), 0.91 (t, J ) 7.1, 3H), 1.04 (s, 3H), 1.0-
1.1 (m, 2H), 1.30-1.58 (m, 3H), 1.61-1.93 (m, 6H), 2.21-2.31
(br, 1H), 2.65 (t, J ) 7.1, 2H), 2.75 (d, J ) 10.4, 1H), 2.79 (d,
J ) 10.4, 1H), 3.76 (dd, J ) 3.3, 7.7, 1H); 13C NMR δ 3.5, 3.8,
13.7, 20.2, 20.9, 25.4, 27.2, 33.6, 34.6, 39.6, 45.7, 47.6, 53.1,
78.7; MS m/z 340 (M+, 130Te), 338 (M+,128Te), 336 (M+, 126Te),
135, 107, 93, 67, 55; HRMS calcd for C14H26OTe 340.1035 (M+,
130Te), found 340.1035.
337, 335, 222, 220, 218, 135, 107, 9. Anal. Calcd for C14H25
ClOTe: C, 45.15; H, 6.77. Found: C, 44.64; H, 6.46.
-
[2R-(2r,3a r,6r,7a â)]-2-Ch lor o-2,2,5,6,7,7a -h exa h yd r o-
8,8-d im et h yl-2-h exyl-4H -3a ,6-m et h a n o-3H -1,2-b en zoxa -
(1S)-10-(Hexyltellu r en yl)-2-exo-bor n eol (2d ). To a solu-
tion of dihexyl ditelluride (245 mg, 0.57 mmol) and (1S)-10-
iodo-2-exo-borneol (324 mg, 1.15 mmol) in absolute EtOH (5
mL) was added NaBH4 (76 mg, 2 mmol) under N2 atmosphere
at 0 °C. The mixture was stirred until the red color of the
ditelluride disappeared (ca. 10 min), and the solution was
heated under reflux for 20 min. The reaction was quenched
with H2O (2 mL) at rt, and the mixture was extracted with
CH2Cl2 (30 mL × 2). The organic layer was washed with H2O
(6 mL × 2) followed by brine (6 mL × 1) and dried over MgSO4.
Removal of the solvent under reduced pressure gave the crude
product, which was purified by column chromatography (hex-
tellu r ole (3d ): [R]26 +44.59° (c 1.00, CHCl3); IR (neat) 2954,
D
1456, 1388, 1046, 987, 870 cm-1; 1H NMR δ 0.88 (s, 3H), 0.84-
1.0 (m, 3H), 1.04 (s, 3H), 1.13-1.5 (m, 8H), 1.68-2.02 (m, 7H),
3.21 (t, J ) 8.2, 2H), 3.34 (d, J ) 13.2, 1H), 3.49 (d, J ) 13.2,
1H), 4.12 (dd, J ) 3.9, 8.8, 1H); 13C NMR δ 20.4, 20.5, 22.6,
25.8, 26.9, 31.0, 31.3, 31.6, 39.1, 42.0, 42.4, 45.6, 46.7, 55.5,
93.3 (a signal will be overlapped with the signal of CDCl3);
MS m/z 404 (M+, 130Te, 37Cl), 402 (M+, 130Te, 35Cl/128Te, 37Cl),
400 (128Te, 35Cl/126Te, 37Cl), 398 (126Te, 35Cl) 367, 365, 363, 250,
248, 246, 135, 107, 85, 55; HRMS calcd for C16H29ClOTe (130Te,
37Cl), (130Te, 37Cl), (130Te, 37Cl), found 404.0965, 402.1005,
402.0941, 400.0923.
ane/EtOAc 9:1) to give 2d (375 mg, 90%) as a red oil: [R]25
[2R-(2r,3a r,6r,7a â)]-2-Ch lor o-2,2,5,6,7,7a -h exa h yd r o-
8,8-d im et h yl-2-p h eyl-4H -3a ,6-m et h a n o-3H -1,2-b en zoxa -
tellu r ole (3e): mp 154-156 °C (colorless prisms); [R]26D +92.3°
(c 0.993, CHCl3); IR (KBr) 3048, 2984, 2947, 2871, 1481, 1453,
1436, 1017, 990, 734, 687 cm-1; 1H NMR δ 0.91 (s, 3H), 0.85-
1.20 (m, 2H), 1.14 (s, 3H), 1.60-2.00 (m, 5H), 3.42 and 3.62
D
-22.48° (c 1.11, CHCl3); IR (neat) 3467, 2926, 1454, 1070, 1040,
1018, 864 cm-1; 1H NMR δ 0.84 (s, 3H), 0.8-1.0 (m, 3H), 1.05
(s, 3H), 1.0-1.15 (m, 2H), 1.23-1.38 (m, 6H), 1.45-1.84 (m,
8H), 2.65 (t, J ) 7.7, 2H), 2.75 (d, J ) 10.5, 1H), 2.81 (d, J )
10.5, 1H), 3.76 (dd, J ) 3.9, 7.7, 1H); 13C NMR δ 3.7, 3.8, 14.3,

Synthesis of Optically Pure Telluronium Salts
J . Org. Chem., Vol. 63, No. 16, 1998 5427
(ABq, J ) 13.4, 2H), 3.81 (dd, J ) 3.3, 1H), 7.50-7.60 (m, 3H),
8.10-8.20 (m, 2H); 13C NMR δ: 20.5, 20.7, 26.8, 31.4, 41.9,
44.0, 45.6, 46.7, 55.4, 93.2, 130.2, 130.9, 131.4, 132.1; MS m/z
395 (M+ - 1) (130Te, 37Cl), 394 (M+) (130Te, 35Cl), 393 (M+ - 1)
(STe)-(-)-Eth yl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im eth ylbi-
cyclo[2.2.1]h ep ta n -1-yl]m eth yl]m eth yltellu r on iu m ch lo-
r id e (4a ): mp 135-136 °C; [R]26 -34.75° (c 1.467, CHCl3);
D
IR (KBr) 3312, 3257, 1475, 1388, 1220, 1078, 868 cm-1
;
1H
(
130Te, 35Cl/128Te, 37Cl), 392 (M+) (128Te, 35Cl/126Te, 37Cl), 391
NMR δ 0.86 (s, 3H), 1.11 (s, 3H), 1.0-1.24 (m, 2H), 1.55 (t, J
) 7.69, 3H), 1.61-2.1 (m, 5H), 2.35 (s, 3H), 2.75 (d, J ) 12.09,
1H), 2.83 (d, J ) 12.09, 1H), 2.97-3.02 (m, 2H), 3.91 (m, 1H),
5.92 (br, 1H); 13C NMR δ 8.1, 10.2, 20.8, 21.0, 21.4, 25.1, 27.5,
34.5, 40.8, 45.6, 48.4, 51.0, 77.1; 125Te NMR δ 498; MS m/z
312, 310, 308, 298, 296, 294, 174, 172, 170, 135, 108, 93, 79,
67, 55. Anal. Calcd for C13H25ClOTe: C, 43.33; H, 6.99.
Found: C, 43.37; H, 7.03.
Crystallographic data for 4a : orthorhombic, space group,
P212121 (#19) with a ) 7.76(8) Å, b ) 25.8(1) Å, c ) 7.60(7) Å,
V ) 1522(18) Å3, and Z ) 4 (dcalcd ) 1.572 g cm-3), µ (MoKR)
) 21.11 cm-1 absorption corrected by ω scans; 2083 unique
reflections; 1621 with I > 3.00σ(I) were used in refinement; R
) 2.8%, Rw ) 2.9%. Selected bond lengths (Å) and angles (deg)
are as follows: Te-C(1), 2.16(2); Te-C(2), 2.083(8); Te-C(3),
2.139(7); C(1)-Te-C(2), 92.9(6); C(1)-Te-C(3), 96.4(3); C(2)-
Te-C(3), 93.4(3). Further details of the crystal structure
investigation are available on request from the Director of the
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge, CB2 1EZ, UK, on quoting the full journal citation.
(M+ - 1) (128Te, 35Cl/126Te, 37Cl), 390 (M+) (126Te, 35Cl), 389 (M+
- 1) (126Te, 35Cl). Anal. Calcd for C16H21OClTe: C, 48.97; H,
5.39. Found: C, 48.97; H, 5.36.
[2R-(2r,3a r,6r,7a â)]-2-Br om o-2,2,5,6,7,7a -h exa h yd r o-
8,8-d im eth yl-2-m eth yl-4H-3a ,6-m eth a n o-3H-1,2-ben zoxa -
tellu r ole (3f): mp 156-157 °C; [R]26D +106.36° (c 1.00, CHCl3);
IR (KBr) 2953, 1454, 1389, 1042, 868 cm-1; 1H NMR δ 0.89 (s,
3H), 1.03 (s, 3H), 1.16-1.27 (m, 2H), 1.59-2.0 (m, 5H), 2.86
(s, 3H), 3.52 (d, J ) 14.0, 1H), 3.69 (d, J ) 14.0, 1H), 4.22 (dd,
J ) 3.3, 7.2, 1H); 13C NMR δ 20.5, 20.6, 21.8, 26.9, 31.7, 41,8,
42.2, 45.7, 46.7, 55.7, 94.3; MS m/z 378 (M+, 130Te, 81Br), 376
(M+, 130Te, 79Br/128Te, 81Br), 374 (M+, 128Te, 79Br/126Te, 81Br),
372 (M+, 126Te, 79Br), 297, 295, 293, 226, 224, 222, 107, 93, 81,
67, 55; HRMS calcd for C11H19BrOTe 375.9688 (130Te, 79Br),
375.9654 (128Te, 81Br), found 375.9704, 375.9628.
[2R-(2r,3a r,6r,7a â)]-2-Br om o-2,2,5,6,7,7a -h exa h yd r o-
8,8-d im et h yl-2-et h yl-4H -3a ,6-m et h a n o-3H -1,2-b en zoxa -
tellu r ole (3g): mp 114-116 °C; [R]26D +93.68° (c 0.62, CHCl3);
1
IR (KBr) 2956, 1455, 1048, 869 cm-1; H NMR δ 0.91 (s, 3H),
1.06 (s, 3H), 1.17-1.23 (m, 2H), 1.59-1.98 (m, 5H), 1.71 (t, J
) 7.7, 3H), 3.2-3.38 (m, 2H), 3.42 (d, J ) 13.7, 1H), 3.56 (d,
J ) 13.7, 1H), 4.17 (dd, J ) 3.3, 7.2, 1H); 13C NMR δ 11.4,
20.6, 20.7, 27.0, 31.6, 35.0, 39.5, 42.3, 45.7, 46.8, 55.6, 94.4;
125Te NMR δ 1865; MS m/z 392 (M+, 130Te, 81Br), 390 (M+, 130Te,
79Br/128Te, 81Br), 388 (M+, 128Te, 79Br/126Te, 81Br), 386 (M+, 126Te,
79Br), 346, 344, 342, 311, 309, 307, 238, 236, 234, 194, 192,
190, 107, 93, 81, 67, 55; HRMS calcd for C12H21BrOTe 389.9844
(RTe)-(-)-Eth yl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im eth ylbi-
cyclo[2.2.1]h ep ta n -1-yl]m eth yl]m eth yltellu r on iu m ch lo-
r id e (4b): mp 159-160 °C; [R]26 -29.72° (c 1.133, CHCl3);
D
IR (KBr) 3213, 2953, 1456, 1252, 1207, 1069 cm-1; 1H NMR δ
0.84 (s, 3H), 1.0-1.2 (m, 2H), 1.10 (s, 3H), 1.55 (t, J ) 7.69,
3H), 1.59-2.1 (m, 5H), 2.32 (s, 3H), 2.59 (d, J ) 11.54, 1H),
2.95 (d, J ) 12.09, 1H), 3.13 (q, 7.69, 2H), 3.90 (dd, J ) 3.3,
7.14, 1H), 5.83 (d, J ) 3.85, 1H); 13C NMR δ 8.0, 10.1, 20.8,
20.9, 22.7, 26.3, 27.5, 34.3, 40.6, 45.5, 48.5, 51.1 (a signal will
be overlapped with the signal of CDCl3); 125Te NMR δ 488;
MS m/z 312, 310, 308, 298, 296, 294, 174, 172, 170, 135, 108,
93, 81, 67, 55. Anal. Calcd for C13H25ClOTe: C, 43.33; H, 6.99.
Found: C, 43.24; H, 7.00.
(
130Te, 79Br), 389.9811 (128Te, 81Br), found 389.9799.
[2R-(2r,3a r,6r,7a â)]-2-Br om o-2,2,5,6,7,7a -h exa h yd r o-
8,8-d im et h yl-2-b u t yl-4H -3a ,6-m et h a n o-3H -1,2-b en zoxa -
tellu r ole (3h ): mp 172-173.5 °C; [R]26 +106.96° (c 1.06,
D
CHCl3); IR (KBr) 2957.8, 1354.1, 1047.4 cm-1; 1H NMR δ 0.88
(s, 3H), 0.97 (t, J ) 7.1, 3H), 1.04 (s, 3H), 1.11-1.25 (m, 2H),
1.42-1.59 (m, 2H), 1.63-2.05 (m, 7H), 3.2-3.4 (m, 2H), 3.48
(d, J ) 13.2, 1H), 3.59 (d, J ) 13.2, 1H), 4.17 (dd, J ) 3.3, 7.2,
1H); 13C NMR δ 13.8, 20.4, 20.6, 24.6, 26.9, 28.2, 31.5, 39.9,
41.5, 42.3, 45.6, 46.7, 55.6, 94.5; 125Te NMR δ 1851; MS m/z
420 (M+, 130Te, 81Br), 418 (M+, 130Te, 79Br/128Te, 81Br), 416 (M+,
128Te, 79Br/126Te, 81Br), 414 (M+, 126Te, 79Br), 339, 337, 335, 266,
264, 262, 222, 220, 218, 135, 107, 93.
Crystallographic data for 4b: orthorhombic, space group,
P212121 (#19) with a ) 9.655(3) Å, b ) 24.241(5) Å, c ) 6.719-
(4) Å, V ) 1572(1) Å3, and Z ) 4 (dcalcd ) 1.522 g cm-3), µ
(MoKR) ) 20.44 cm-1 absorption corrected by ω scans; 2122
unique reflections; 1352 with I > 3.00σ(I) were used in
refinement; R ) 3.3%, Rw ) 3.4%. Selected bond lengths (Å)
and angles (deg) are as follows: Te-C(1), 2.153(1); Te-C(2),
2.14(1); Te-C(3), 2.093(8); C(1)-Te-C(2), 92.1(4); C(1)-Te-
C(3), 96.5(4); C(2)-Te-C(3), 94.4(4). Further details of the
crystal structure investigation are available on request from
the Director of the Cambridge Crystallographic Data Centre,
12 Union Road, Cambridge, CB2 1EZ, UK, on quoting the full
journal citation.
[2R-(2r,3a r,6r,7a â)]-2-Br om o-2,2,5,6,7,7a -h exa h yd r o-
8,8-d im eth yl-2-p h en yl-4H-3a ,6-m eth a n o-3H-1,2-ben zoxa -
tellu r ole (3i): mp 143-144 °C (colorless prisms, recrystallized
from hexane-AcOEt); [R]25D +143.5° (c 1.00, CHCl3); IR (KBr)
3047, 2939, 2868, 1435, 1045, 733 cm-1 1H NMR δ 0.89 (s,
;
3H), 0.80-1.20 (m, 2H), 1.13 (s, 3H), 1.60-1.95 (m, 5H), 3.58
and 3.74 (ABq, J ) 13.2, 2H), 3.80-3.85 (m, 1H), 7.50-7.60
(m, 3H), 8.10-8.20 (m, 2H); 13C NMR δ 20.4, 20.6, 26.7, 31.4,
42.1, 44.9, 45.5, 46.7, 55.5, 93.8, 129.4, 130.2, 131.4 132.5; MS
m/z 441 (M+ + 1) (130Te, 81Br), 440 (M+) (130Te, 81Br), 439 (M+
+ 1) (130Te, 79Br/128Te, 81Br)/(M+ - 1) (130Te, 81Br), 438 (M+)
(STe)-(-)-Bu tyl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im eth ylbi-
cyclo[2.2.1]h ep ta n -1-yl]m eth yl]m eth yltellu r on iu m ch lo-
r id e (4c): mp 146-148 °C; [R]26 -37.24° (c 2.53, CHCl3); IR
D
(KBr) 3328, 2955, 1456, 1073, 868 cm-1
;
1H NMR δ 0.85 (s,
3H), 0.95 (t, J ) 7.14, 3H), 1.09 (s, 3H), 1.0-1.22 (m, 2H),
1.42-1.60 (m, 3H), 1.68-1.84 (m, 6H), 2.0-2.2 (m, 1H),2.41
(s, 3H), 2.75 (d, J ) 12.09, 1H), 2.90 (d, J ) 12.64, 1H), 2.91-
3.31 (m 1H), 3.90 (dd, J ) 3.3, 7.7, 1H), 5.80-5.85 (br, 1H);
13C NMR δ 9.0, 13.8, 20.8, 20.8, 24.8, 26.2, 27.2, 27.5, 27.6,
34.4, 40.7, 45.5, 48.4, 51.1, 77.0; 125Te NMR δ 481; MS m/z
340, 338, 336, 298, 296, 294, 202, 200, 198, 135, 108, 93, 79,
57. Anal. Calcd for C15H29ClOTe: C, 46.39; H, 7.53. Found:
C, 46.09; H, 7.47.
(
130Te, 79Br/128Te, 81Br), 437 (M+ + 1) (128Te, 79Br/126Te, 81Br)/
(M+ - 1) (130Te, 79Br/130Te, 81Br), 436 (M+) (128Te, 79Br/126Te,
81Br), 435 (M+ + 1) (126Te, 79Br)/(M+ - 1) (128Te, 79Br/126Te,
81Br), 434 (M+) (126Te, 79Br), 433 (M+ - 1) (126Te, 79Br). Anal.
Calcd for C16H21OBrTe: C, 43.99; H, 4.85. Found: C, 44.04;
H, 4.79.
Gen er a l P r oced u r e for Syn th esis of Tellu r on iu m Sa lts
4a -i a n d 5a -h . To a solution of tellurane (0.2 mmol) in CH2-
Cl2 (6 mL) was added RLi (or RMgX) (0.24 mmol, 1.2 equiv)
dropwise at -78 °C under N2. The reaction mixture was
stirred and allowed to warm to 0 °C during ca. 1 h. Then the
mixture was stirred at 0 °C for another 1 h. The reaction was
quenched with saturated aqueous NH4Cl solution (4 mL),
followed by extraction with CH2Cl2 (35 mL × 2). The combined
organic layers were washed with H2O (5 mL × 2) and brine (5
mL × 1), dried over MgSO4, and then concentrated to dryness.
Purification of the residue by recrystallization from hexane
and CH2Cl2 afforded colorless crystalline products.
(RTe)-(-)-Bu tyl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im eth ylbi-
cyclo[2.2.1]h ep ta n -1-yl]m eth yl]m eth yltellu r on iu m ch lo-
r id e (4d ): mp 165-166 °C; [R]26 -25.69° (c 1.80, CHCl3); IR
D
(KBr) 3212, 2953, 1454, 1209, 1069 cm-1; H NMR δ 0.87 (s,
1
3H), 0.98 (s, 3H), 1.0-1.2 (m, 2H), 1.14 (s, 3H), 1.4-1.6 (m,
3H), 1.42-1.92 (m, 6H), 1.62-1.92 (m, 6H), 2.38 (s, 3H), 2.69
(d, J ) 12.09, 1H), 2.98 (d, J ) 12.09, 1H), 2.97-3.12 (m, 2H),
3.94 (dd, J ) 3.85, 7.7, 1H), 6.0 (d, J ) 3.85, 1H); 13C NMR δ
9.00, 13.84, 20.8, 21.1, 24.9, 27.1, 27.5, 27.6, 28.8, 34.5, 40.7,
45.6, 48.4, 51.1, 76.8; 125Te NMR δ 477; MS m/z 338, 336, 334,
298, 296, 294, 202, 200, 198, 146, 144, 142, 108, 93, 79, 57.

5428 J . Org. Chem., Vol. 63, No. 16, 1998
Zhang et al.
Anal. Calcd for C15H29ClOTe: C, 46.38; H, 7.53. Found: C,
46.65; H, 7.53.
(STe)-(-)-Ben zyleth yl[[(1S,2R,4R)-2-h ydr oxy-7,7-dim eth -
ylbicyclo[2.2.1]h ep ta n -1-yl]m eth yl]tellu r on iu m ch lor id e
(5b): mp 145-146 °C; [R]26D -93.30° (c 2.30, CHCl3); IR (KBr)
3204, 2943, 1454, 1073, 755 cm-1; 1H NMR δ 0.80 (s, 3H), 0.9-
1.1 (m, 2H), 1.27-1.34 (m, 1H), 1.48 (t, J ) 7.7, 3H), 1.61-
1.95 (m, 5H), 2.24 (d, J ) 12.6, 1H), 2.49 (d, J ) 12.4, 1H),
2.45-2.60 (m, 1H), 3.04-3.20 (m, 1H), 3.94 (dd, J ) 3.3, 7.7,
1H), 4.53 (d, J ) 11.5, 1H), 4.63 (d, J ) 11.5, 1H), 7.28-7.41
(m, 5H); 13C NMR δ 10.8, 20.7, 21.4, 22.9, 23.8, 27.3, 33.0, 34.5,
41.0, 45.6, 48.2, 50.1, 76.9, 128.2, 129.0, 130.4, 132.6; 125Te
NMR δ 588; MS m/z 374, 372, 370, 312, 310, 308, 135, 91, 79,
57. Anal. Calcd for C19H29ClOTe: C, 52.28; H, 6.70. Found:
C, 52.05; H, 6.67.
(STe)-(-)-Bu tyleth yl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im eth -
ylbicyclo[2.2.1]-h ep ta n -1-yl]m eth yl]tellu r on iu m ch lor id e
(4e): oil; [R]26 -23.05° (c 1.14, CHCl3); IR (KBr) 3269, 2956,
D
1456, 1075, 730 cm-1; 1H NMR δ 0.88 (s, 3H), 0.98 (t, J ) 7.14,
3H), 1.12 (s, 3H), 0.8-1.24 (m, 2H), 1.44-1.55 (m, 3H), 1.60
(t, J ) 7.69, 3H), 1.71-1.88 (m, 6H), 2.2-2.4 (m, 1H),2.63 (d,
J ) 11.54, 1H), 2.8-3.21 (m, 5H), 3.93 (dd, J ) 3.3, 7.1, 1H);
13C NMR δ 10.7, 13.8, 20.7, 20.8, 22.4, 24.9, 25.0, 26.1, 27.4,
28.1, 28.3, 34.4, 40.8, 45.5, 48.5, 50.9 (a signal will be
overlapped with the signal of CDCl3); MS m/z 340, 338, 336,
298, 296, 294, 202, 200, 198, 135, 108, 93, 79, 57.
Crystallographic data for 5b: monoclinic, space group, C2
(#5) with a ) 26.128(2) Å, b ) 6.694(2) Å, c ) 12.842(1) Å, V
) 1998.1(6) Å3, and Z ) 4 (dcalcd ) 1.451 g cm-3), µ (MoKR) )
16.23 cm-1 absorption corrected by ω scans; 2479 unique
reflections; 2056 with I > 3.00σ(I) were used in refinement; R
) 6.1%, Rw ) 7.9%. Selected bond lengths (Å) and angles (deg)
are as follows: Te-C(1), 2.16(1); Te-C(2), 2.13(2); Te-C(3),
2.15(1); Te‚‚‚O, 2.84(1); Te‚‚‚Cl, 3.150(3); C(1)-Te-C(2), 93.5-
(7); C(1)-Te-C(3), 95.8(6); C(2)-Te-C(3), 80.1(7); Cl‚‚‚Te‚‚‚
O, 87.8(3); Cl‚‚‚Te-C(1), 90.9(4); Cl‚‚‚Te-C(2), 110.7(5); Cl‚‚‚
Te-C(3), 167.0(5); O‚‚‚Te-C(1), 69.4(6); O‚‚‚Te-C(2), 155.4(6);
O‚‚‚Te-C(3), 84.1(5). Further details of the crystal structure
investigation are available on request from the Director of the
Cambridge Crystallographic Data Centre, 12 Union Road,
Cambridge, CB2 1EZ, UK, on quoting the full journal citation.
(STe)-(-)-Ben zylbu tyl[[(1S,2R,4R)-2-h ydr oxy-7,7-dim eth -
ylbicyclo[2.2.1]h ep ta n -1-yl]m eth yl]tellu r on iu m ch lor id e
(5c): mp 113-115 °C; [R]26D -84.34° (c 1.20, CHCl3); IR (KBr)
(RTe)-(-)-Bu tyleth yl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im eth -
ylbicyclo[2.2.1]-h ep ta n -1-yl]m eth yl]tellu r on iu m ch lor id e
(4f): mp 99-101.5 °C; [R]26D -45.30° (c 2.10, CHCl3); IR (KBr)
3328, 2954, 1454, 1074, 868 cm-1; 1H NMR δ 0.86 (s, 3H), 0.95
(t, J ) 7.14, 3H), 1.12 (s, 3H), 1.0-1.23 (m, 2H), 1.40-1.50
(m, 2H), 1.57 (t, J ) 7.69, 3H), 1.62-2.03 (m, 7H), 2.69 (d, J
) 12.09, 1H), 2.77 (d, J ) 12.64, 1H), 2.75-2.83 (m 1H), 2.96-
3.20 (m, 3H), 3.91 (m, 1H), 6.1-6.2 (br, 1H); 13C NMR δ 10.7,
10.8, 13.8, 20.8, 21.3, 23.8, 25.0, 27.1, 27.4, 28.0, 34.8, 40.9,
45.7, 48.3, 50.6, 76.9; 125Te NMR δ 549; MS m/z 340, 338, 336,
312, 310, 308, 216, 214, 212, 160, 158, 156, 135, 108, 93, 79,
57.
(STe)-(+)-[[(1S,2R,4R)-2-Hyd r oxy-7,7-d im eth ylbicyclo-
[2.2.1]h eptan -1-yl]m eth yl]m eth ylph en yltellu r on iu m ch lo-
r id e (4g): mp 138-139 °C; [R]26 +9.76° (c 1.00, CHCl3); IR
D
(KBr) 3424, 2950, 1456, 1071, 735 cm-1
;
1H NMR δ 0.76 (s,
3H), 0.95-1.20 (m, 2H), 1.07 (s, 3H), 1.2-1.4 (m, 1H), 1.58-
1.97 (m, 5H), 2.83 (s, 3H), 2.94 (d, J ) 12.6, 1H), 3.30 (d, J )
12.6, 1H), 4.07 (dd, J ) 3.3, 7.7, 1H), 7.4-7.6 (m, 3H), 7.70-
7.85 (m, 2H); 13C NMR δ 15.8, 20.6, 21.5, 27.5, 33.1, 35.3, 40.7,
44.5, 45.9, 47.9, 51.1, 130.2, 130.3, 131.5, 131.7; 125Te NMR δ
564; MS m/z 360, 358, 356, 222, 220, 218, 207, 205, 203, 135,
93, 77. Anal. Calcd for C17H25ClOTe: C, 49.99; H, 6.17.
Found: C, 50.21; H, 5.92.
3328, 2956, 1455, 1074, 701 cm-1 1H NMR δ 0.80 (s, 3H),
;
0.85-1.1 (m, 2H), 0.92 (t, J ) 7.1, 3H), 1.11 (s, 3H), 1.31-
1.45 (m, 4H), 1.62-1.88 (m, 6H), 2.20 (d, J ) 12.6, 1H), 2.40
(d, J ) 12.4, 1H), 2.34-2.41 (m, 1H), 2.95-3.01 (m, 1H), 3.96
(dd, J ) 3.3, 7.7, 1H), 4.60 (d, J ) 11.5, 1H), 4.67 (d, J ) 11.5,
1H), 7.26-7.41 (m, 5H); 13C NMR δ 13.8, 20.7, 21.6, 23.9, 25.1,
27.3, 27.9, 28.5, 33.3, 34.6, 41.0, 45.5, 45.7, 48.1, 50.0, 77.0,
128.2, 129.0, 130.5, 132.6; MS m/z 340, 338, 336, 188, 186, 184,
135, 91, 79, 57.
(STe)-(-)-Eth yl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im eth ylbi-
cyclo[2.2.1]h ep ta n -1-yl]m eth yl]p h en yltellu r on iu m ch lo-
r id e (4h ): mp 117-119 °C; [R]26 -0.045° (c 1.16, CHCl3); IR
D
(STe)-(-)-Ben zylh exyl[[(1S,2R,4R)-2-h ydr oxy-7,7-dim eth -
ylbicyclo[2.2.1]h ep ta n -1-yl]m eth yl]tellu r on iu m ch lor id e
(5d ): mp 100-102 °C; [R]26D -59.96° (c 0.40, CHCl3); IR (KBr)
(KBr) 3187, 2956, 1438, 1068, 742 cm-1
;
1H NMR δ 0.74 (s,
3H), 0.9-1.15 (m, 1H), 1.05 (s, 3H), 1.27-1.34 (m, 1H), 1.44
(t, J ) 7.7, 3H), 1.66-1.86 (m, 6H), 2.95 (d, J ) 12.09, 1H),
3.35-3.41 (m, 2H), 3.56-3.60 (m, 1H), 4.05 (dd, J ) 3.3, 7.1,
1H), 7.47-7.55 (m, 3H), 7.78-7.80 (m, 2H); 13C NMR δ 11.1,
20.6, 21.6, 27.4, 28.3, 29.2, 35.3, 40.8, 45.9, 47.9, 50.7, 77.4,
123.6, 130.2, 131.5, 134.0; MS m/z 360, 358, 356, 284, 282, 280,
236, 234, 232, 208, 206, 204, 135, 109, 93, 77. Anal. Calcd
for C18H27ClOTe: C, 51.18; H, 6.44. Found: C, 51.01; H, 6.40.
3420, 2953, 1455, 1074, 701 cm-1 1H NMR δ 0.71 (s, 3H),
;
0.82-1.0 (m, 2H), 0.77 (t, J ) 6.7, 3H), 1.00 (s, 3H), 1.22-
1.49 (m, 6H), 1.51-1.82 (m, 8H), 2.21 (d, J ) 12.6, 1H), 2.34-
2.44 (m, 1H), 2.46 (d, J ) 12.1, 1H), 2.83-2.92 (m, 1H), 3.85
(dd, J ) 3.3, 7.7, 1H), 4.38 (d, J ) 11.5, 1H), 4.43 (d, J ) 11.5,
1H), 7.16-7.31 (m, 5H); 13C NMR δ 14.2, 20.8, 21.5, 22.7, 25.3,
26.1, 27.4, 29.3, 31.5, 31.7, 33.0, 34.6, 41.0, 45.7, 48.3, 50.4,
76.9, 128.3, 129.1, 130.3, 132.7; MS m/z 366, 364, 362, 306,
304, 302, 214, 212, 210, 135, 91, 79, 57.
(STe)-(-)-Bu tyl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im eth ylbi-
cyclo[2.2.1]h ep ta n -1-yl]m eth yl]p h en yltellu r on iu m ch lo-
r id e (4i): oil; [R]26 -6.47° (c 1.66, CHCl3); IR (KBr) 3236,
D
(STe)-(+)-Ben zyl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im eth ylbi-
2956, 1436, 1072, 738 cm-1
;
1H NMR δ 0.73 (s, 3H), 0.84-
cyclo[2.2.1]h ep ta n -1-yl]m eth yl]p h en yltellu r on iu m ch lo-
r id e (5e): mp 132-133 °C; [R]26 +14.02° (c 0.65, CHCl3); IR
1.20 (m, 2H), 0.86 (t, J ) 7.1, 3H), 1.04 (s, 3H), 1.31-1.46 (m,
4H), 1.66-1.88 (m, 6H), 3.06 (d, J ) 12.09, 1H), 3.31-3.40
(m, 1H), 3.51 (d, J ) 12.09, 1H), 3.60-3.75 (m 1H), 4.09 (dd,
J ) 3.3, 7.1, 1H), 7.3-7.54 (m, 3H), 7.79-7.82 (m, 2H); 13C
NMR δ 13.7, 20.5, 21.4, 24.6, 27.4, 28.2, 35.3, 35.4, 40.6, 45.9,
46.0, 47.8, 50.8, 77.5, 130.3, 130.4, 131.7, 133.9; MS m/z 360,
358, 356, 264, 262, 260, 242, 240, 238, 208, 206, 204, 135, 93,
77, 57.
D
(KBr) 3448, 2948, 1454, 1077, 690 cm-1
;
1H NMR δ 0.73 (s,
3H), 0.87-1.10 (m, 2H), 1.12 (s, 3H), 1.51-1.60 (m, 6H), 1.74-
1.88 (m, 5H), 3.08 (d, J ) 11.5, 1H), 3.80 (d, J ) 11.5, 1H),
4.00 (dd, J ) 3.3, 7.7, 1H), 4.66 (d, J ) 11.0, 1H), 4.85 (d, J )
11.0, 1H), 7.08-7.10 (m, 1H), 7.2-7.28 (m, 1H), 7.35-7.40 (m,
1H), 7.43-7.47 (m, 1H), 7.52-7.55 (m, 1H); 13C NMR δ 20.3,
20.8, 27.8, 33.8, 33.9, 39.9, 41.5, 45.4, 49.3, 52.2, 76.9, 124.0,
128.7, 130.1, 131.7, 131.8, 133.6, 133.9; 125Te NMR δ 361; MS
m/z 366, 364, 362, 306, 304, 302, 214, 212, 210, 135, 91, 79,
57. Anal. Calcd for C23H29ClOTe: C, 57.01; H, 6.03. Found:
C, 56.98; H, 5.70.
(STe)-(-)-Ben zyl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im eth ylbi-
cyclo[2.2.1]h ep ta n -1-yl]m eth yl]m eth yltellu r on iu m ch lo-
r id e (5a ): mp 134-135 °C; [R]26 -70.60° (c 1.47, CHCl3); IR
D
(KBr) 3386, 2950, 1454, 1073, 758 cm-1
;
1H NMR δ 0.82 (s,
3H), 1.0-1.20 (m, 2H), 1.09 (s, 3H), 1.4-1.5 (m, 1H), 1.65-
1.93 (m, 5H), 2.12 (s, 3H), 2.38 (d, J ) 12.6, 1H), 2.46 (d, J )
12.4, 1H), 3.96 (dd, J ) 3.3, 7.7, 1H), 4.48 (d, J ) 11.5, 1H),
4.60 (d, J ) 11.5, 1H), 7.27-7.42 (m, 5H); 13C NMR δ 9.9, 20.8,
21.1, 25.6, 27.4, 33.1, 34.5, 40.9, 45.6, 48.3, 50.6, 128.4, 129.0,
130.5, 132.3 (a signal will be overlapped with the signal of
CDCl3); 125Te NMR δ 522; MS m/z 374, 372, 370, 298, 296,
294, 135, 91, 79, 57. Anal. Calcd for C18H27ClOTe: C, 51.18;
H, 6.44. Found: C, 51.02; H, 6.43.
(STe)-(-)-Allyl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im et h ylb i-
cyclo[2.2.1]h ep ta n -1-yl]m eth yl]m eth yltellu r on iu m ch lo-
r id e (5f): mp 144-145 °C; [R]26 -27.12° (c 1.8, CHCl3); IR
D
(KBr) 3431, 2947, 1627, 1388, 1072 cm-1; H NMR δ 0.85 (s,
1
3H), 1.0-1.2 (m, 2H), 1.11 (s, 3H), 1.5-2.1 (m, 6H), 2.26 (s,
3H), 2.69 (d, J ) 12.09, 1H), 2.75 (d, J ) 12.09, 1H), 3.68-
3.75 (m, 1H), 3.85-3.95 (m, 2H), 5.30-5.41 (m, 2H), 5.82-
5.91 (m, 1H); 13C NMR δ 8.9, 20.9, 20.9, 25.3, 27.5, 30.5, 34.5,
40.7, 45.5, 48.4, 51.0, 77.1, 123.2, 128.3; MS m/z 324, 322, 320,

Synthesis of Optically Pure Telluronium Salts
J . Org. Chem., Vol. 63, No. 16, 1998 5429
298, 296, 294, 265, 263, 261, 135, 107, 93, 79, 67, 55. Anal.
Calcd for C14H25ClOTe: C, 45.15; H, 6.77. Found: C, 45.50;
H, 6.73.
r id e (5h ): mp 106-108 °C; [R]26 +33.36° (c 1.05, CHCl3); IR
D
(KBr) 3398, 2950, 1436, 1047 cm-1; H NMR δ 0.80 (s, 3H),
1
1.0-1.38 (m, 2H), 1.10 (s, 3H), 1.61-2.0 (m, 6H), 2.81 (d, J )
12.1, 1H), 3.20 (d, J ) 12.1, 1H), 4.01 (dd, J ) 3.85, 7.14, 1H),
4.12-4.38 (m, 2H), 5.22-5.38 (m, 2H), 5.65-5.82 (m, 1H),
7.44-7.54 (m, 3H), 7.77-7.80 (m, 2H); 13C NMR δ 20.7, 21.7,
27.5, 29.3, 35.5, 37.8, 40.8, 46.0, 47.8, 50.9, 77.5, 124.0, 128.2,
130.2, 130.3, 131.6, 133.8; 125Te NMR δ 482; MS m/z 358, 356,
354, 283, 281, 279, 130, 128, 126, 59.
(STe)-(-)-Allyleth yl[[(1S, 2R, 4R)-2-h yd r oxy-7,7-d im eth -
ylbicyclo[2.2.1] h ep ta n -1-yl]m eth yl]tellu r on iu m ch lor id e
(5g): oil; [R]26 -29.62° (c 1.65, CHCl3); IR (KBr) 3270, 2952,
D
1628, 1388, 1074 cm-1
;
1H NMR δ 0.87 (s, 3H), 1.0-1.3 (m,
2H), 1.13 (s, 3H), 1.58 (t, J ) 7.4, 3H), 1.5-2.0 (m, 6H), 2.70
(d, J ) 12.1, 1H), 2.77 (d, J ) 12.1, 1H), 2.8-2.9 (m, 1H), 2.99-
3.18 (m, 1H), 3.65-3.97 (m, 3H), 5.30-5.42 (m, 2H), 5.82-
6.04 (m, 1H); 13C NMR δ 10.9, 20.9, 21.2, 22.2, 27.5, 30.2, 34.7,
40.8, 45.6, 45.7, 48.5, 50.8, 76.9, 122.9, 128.7; MS m/z 337, 335,
333, 324, 322, 320, 312, 310, 308, 135, 109, 93, 79.
Ack n ow led gm en t. This work was supported by
Grants-in-Aid for Scientific Research from the Ministry
of Education, Science, Sports and Culture, J apan.
(STe)-(-)-Allyl[[(1S,2R,4R)-2-h yd r oxy-7,7-d im et h ylb i-
cyclo[2.2.1]h ep ta n -1-yl]m eth yl]p h en yl tellu r on iu m ch lo-
J O9803131