Organostannanes Derived from (-)-Menthol: Controlling Stereochemistry during the Preparation of (1R,2S,5R)-Menthyldiphenyltin Hydride and Bis((1R,2S,5R)-menthyl)phenyltin Hydride

Article abstract of DOI:10.1021/om990088t

Reaction of (1R,2S,5R)-menthylmagnesium chloride (MenMgCl) with triphenyltin chloride in THF proceeds with epimerization of the C-1 carbon of the menthyl group and results in a mixture of (1R,2S,5R)-menthyltriphenyltin (1) and (1S,2S,5R)-menthyltriphenyltin (2). Addition of Lewis bases such as triphenylphosphine to the THF solution of triphenyltin chloride prior to addition of the Grignard reagent suppresses epimerization and enables isolation of pure 1. An epimerization mechanism involving one-electron-transfer reactions is postulated. Compound 1 is the precursor for reactions that lead to the formation of a series of compounds, namely, (1S,2S,5R)-menthyldiphenyltin iodide (4), (1S,2S,5R)-menthyldiphenyltin fluoride (5), (1S,2S,5R)-menthyldiphenyltin hydride (6), (1S,2S,5R)-menthylphenyltin dibromide (7), and (1S,2S,5R)-menthylphenyltin dichloride (8). The synthesis of the dimenthyl derivatives bis((1S,2S,5R)-menthyl)diphenyltin (9), bis((1S,2S,5R)-menthyl)-phenyltin iodide (10), bis((1S,2S,5R)-menthyl)phenyltin hydride (11), and bis((1S,2S,5R)-menthyl)tin di(chloroacetate) (12) is described. Crystal structure determinations of 7,8, and 12 confirm the absolute configuration of the menthyl groups.

Full text of DOI:10.1021/om990088t

3
342
Organometallics 1999, 18, 3342-3347
Or ga n osta n n a n es Der ived fr om (-)-Men th ol: Con tr ollin g
Ster eoch em istr y d u r in g th e P r ep a r a tion of
(
1R,2S,5R)-Men th yld ip h en yltin Hyd r id e a n d
Bis((1R,2S,5R)-m en th yl)p h en yltin Hyd r id e
Dainis Dakternieks,* Kerri Dunn, and David J . Henry
Centre for Chiral and Molecular Technologies, Deakin University,
Geelong Victoria 3217, Australia
Carl H. Schiesser*
School of Chemistry, The University of Melbourne, Parkville Victoria 3052, Australia
Edward R. T. Tiekink*
Department of Chemistry, The University of Adelaide, South Australia 5005, Australia
Received February 10, 1999
Reaction of (1R,2S,5R)-menthylmagnesium chloride (MenMgCl) with triphenyltin chloride
in THF proceeds with epimerization of the C-1 carbon of the menthyl group and results in
a mixture of (1R,2S,5R)-menthyltriphenyltin (1) and (1S,2S,5R)-menthyltriphenyltin (2).
Addition of Lewis bases such as triphenylphosphine to the THF solution of triphenyltin
chloride prior to addition of the Grignard reagent suppresses epimerization and enables
isolation of pure 1. An epimerization mechanism involving one-electron-transfer reactions
is postulated. Compound 1 is the precursor for reactions that lead to the formation of a
series of compounds, namely, (1S,2S,5R)-menthyldiphenyltin iodide (4), (1S,2S,5R)-men-
thyldiphenyltin fluoride (5), (1S,2S,5R)-menthyldiphenyltin hydride (6), (1S,2S,5R)-men-
thylphenyltin dibromide (7), and (1S,2S,5R)-menthylphenyltin dichloride (8). The synthesis
of the dimenthyl derivatives bis((1S,2S,5R)-menthyl)diphenyltin (9), bis((1S,2S,5R)-menthyl)-
phenyltin iodide (10), bis((1S,2S,5R)-menthyl)phenyltin hydride (11), and bis((1S,2S,5R)-
menthyl)tin di(chloroacetate) (12) is described. Crystal structure determinations of 7, 8, and
1
2 confirm the absolute configuration of the menthyl groups.
In tr od u ction
Over recent years there has been a growing interest
Despite the potential uses of organostannanes con-
taining elements of chirality, there are still few such
compounds which are well characterized, and most of
in the preparation of organostannanes that contain
chiral organic substituents as well as organostannanes
in which the tin center itself is chiral. This interest
arises primarily because of the enormous potential of
such compounds as chiral information transfer agents
these contain the naturally occurring menthyl group as
8-11
an organo substituent.
In some cases there has been
crystallographic evidence for retention of configuration
of the menthyl group after reaction with the tin center;
in other cases spectroscopic data are used to support
retention of configuration during the transfer of the
organic group. The syntheses of triorganostannanes
containing the (1R,2S,5R)-menthyl substituent (Men)
have been achieved previously from reaction between
triorganotin chlorides, R3SnCl (R ) methyl, neophyl)
and the corresponding Grignard reagent. In both cases
transfer of the menthyl group is reported to occur with
retention of configuration of the C-1 stereocenter. To the
best of our knowledge there have been no reports of
corresponding syntheses starting from other triorgano-
tin chlorides containing other organic substituents. In
1
-3
in a range of organic syntheses.
Very recently the
surface organometallic chemistry of chiral organostan-
4
nanes has been investigated, as has their utility in
5
heterogeneous catalysis. Our own interest is in devel-
opment of organotin hydrides as enantioselective free
6
,7
radical reducing agents for rational organic synthesis.
(1) Pereyre, M.; Quintard, J . P.; Rahm, A. Tin in Organic Synthesis;
Butterworth: London, 1987.
(
(
2) Neumann, W. P. Synthesis 1987.
3) Omae, I. Organotin Chemistry, J ournal of Organometallic
Chemistry Library Series, Vol. 21; Elsevier Science Publishers B. V.:
Amsterdam, 1989.
(
4) de Mallmann, A.; Lot, O.; Perrier, N.; Lefebvre, F.; Santini, C.
C.; Basset, J . M. Organometallics 1998, 17, 1031-1043.
5) Lucas, C.; Santini, C.; Prinz, M.; Cordinnier, M.; Basset, J .;
Connil, M.; J ousseaume, B. J . Organomet. Chem. 1996, 520, 102.
6) Dakternieks, D.; Henry, D. J .; Schiesser, C. H. Organometallics
998, 17, 1079.
7) Dakternieks, D.; Henry, D. J .; Schiesser, C. H. J . Chem. Soc.,
Perkin Trans. 1997, 2, 1665.
(8) Schumann, H.; Wassermann, B. C.; Pickardt, J . Organometallics
1993, 12, 3051.
(9) Schumann, H.; Wassermann, B. C.; Hahn, E. Organometallics
1992, 11, 2803.
(10) Podesta, J .; Chopa, A. B.; Radivoy, G. E. J . Organomet. Chem.
1995, 494, 11.
(11) Podesta, J . C.; Radivoy, G. E. Organometallics 1994, 13, 3364.
(
(
1
(
1
0.1021/om990088t CCC: $18.00 © 1999 American Chemical Society
Publication on Web 07/21/1999

Organostannanes Derived from (-)-Menthol
Organometallics, Vol. 18, No. 17, 1999 3343
this paper we report the synthesis of (1R,2S,5R)-
menthyltriphenyltin (MenPh3Sn), as well as a series of
related compounds containing one or more menthyl
substituents on the tin center. We also report the X-ray
structure analyses of three compounds that confirm
retention of the configuration of stereogenic centers of
the menthyl group during the synthetic transformations
described.
Sch em e 1
Resu lts a n d Discu ssion
P r ep a r a tion of (1R,2S,5R)-Men th yltr ip h en yltin ,
Men P h 3Sn (1). Reaction of 1.1 molar equiv of the
Grignard reagent MenMgCl with Ph3SnCl in tetrahy-
drofuran (THF) results in substantial epimerization of
the C-1 carbon of the menthyl group, and the two
compounds ((1R,2S,5R)-menthyl)triphenyltin (1) and
(
(1S,2S,5R)-menthyl)triphenyltin (2) are formed in the
1
19
ratio of 3:2, as evidenced by Sn NMR spectroscopy (δ
111.2, -108.1). Also evident in the reaction mixture
-
nBu3SnCl, and Ph3SnCl, suggest that the nature of the
triorganotin reagent may influence the configurational
stability of the C-1 carbon atom within the menthyl
group.
are significant quantities of hexaphenylditin, (Ph3Sn)2.
Changing the reaction solvent to toluene, hexane, di-
ethyl ether, or di-n-butyl ether has little effect on the
ratio of the two isomeric products. Attempts at the
preparation of MenPh3Sn (1) from reaction of Ph3SnM
Reactions between Ph3SnCl and MenMgCl were re-
peated in the presence of a number of Lewis bases such
(
M ) Na or Li) with MenCl produced only hexaphen-
n
as LiI, Bu4NI, (Ph2P)2(CH2)2, Ph3P, (cyclohexyl)3P, and
ylditin, (Ph3Sn)2. Addition of MenCl to magnesium and
n
Ph3SnCl in THF12 gave no reaction.
Bu P(O) in order to probe whether epimerization is
3
related to the Lewis acidity of the triorganotin precur-
sor. In each case the addition of 1 molar equiv of Lewis
base to the solution of Ph3SnCl prior to reaction with
MenMgCl suppressed epimerization within the menthyl
group, and only a single isomer was observed in the
1
19
Sn NMR spectrum of the reaction mixture (δ -111.2).
The Lewis base of choice was Ph3P because of low cost
and ease of removal, which was achieved by recrystal-
lization and oxidative removal of residual Ph3P by
treatment with tert-butylhydroperoxide. There was no
formation of (1S,2S,5R)-menthyltriphenyltin when the
concentration of Ph3P was reduced to 0.15 molar equiv;
however, using less than 0.15 molar equiv of Ph3P
resulted in formation of significant quantities of the
unwanted isomer, as did reaction times beyond 2 h.
Scheme 1 summarizes a plausible set of equilibria
consistent with the above observations. The first step
involves a one-electron transfer from the Grignard
reagent to the Lewis acidic tin center in Ph3SnCl.
Subsequent dissociation of the radical cation (Men-
It was reported previously13 that MenMgCl reacts
with chlorodiphenylphosphine (Ph2PCl) with retention
of configuration at the C-1 of the menthyl group to form
exclusively MenPh2P. In that report the product was
purified by distillation prior to NMR characterization,
which allows for the possibility that any of the epimeric
(
(1S,2S,5R)-menthyl)diphenylphosphine isomer that
formed could have been removed and therefore remain
undetected. We repeated the reaction of MenMgCl with
Ph2PCl and investigated the reaction mixture prior to
1
any purification. The H NMR (CDCl3) spectrum of the
reaction mixture showed that only MenPh2P was pro-
duced, confirming that the Grignard reagent itself is
configurationally stable, thereby eliminating it as the
source of epimerization in its reaction with triorganotin
halides.
+.
MgCl ) gives rise to the menthyl radical (3), which has
lost its original stereochemical integrity due to the
planar geometry associated with the carbon-centered
•-
π-radical at C-1. The radical anion (Ph3Sn ) presum-
ably undergoes dissociation to give the triphenylstannyl
radical, which undergoes radical coupling to form
hexaphenylditin, (Ph3Sn)2.
n
We find that the reaction of the MenMgCl with Bu3-
SnCl in THF or diethyl ether gives a 3:1 mixture of
n
Men Bu3Sn and (1S,2S,5R)-menthyltributyltin, as well
We speculate that addition of Ph3P results in sub-
stantial interaction of the Lewis base with the Ph3SnCl.
The resulting adduct (Ph3SnCl‚PPh3) would be expected
to have different electronic properties from those of
Ph3SnCl, which inhibit one-electron transfer from the
Grignard reagent. Suppression of the radical pathways
enables attachment of the menthyl substituent to tin
without inversion and without formation of (Ph3Sn)2.
Compound 1 forms the basis for the synthesis of the
series of new compounds outlined in Scheme 2.
as quantities of hexabutylditin. In contrast, it has been
reported that reaction of MenMgCl with Me3SnCl
results in no change of stereochemistry within the
menthyl group, and a single compound MenMe3Sn was
9
obtained in good yield. The different ratios of isomers
obtained from reaction of MenMgCl with the three
different triorganotin chloride precursors, Me3SnCl,
(
12) Blomberg, C.; Hartog, F. A. Synthesis 1977, 18, 18.
(13) Tanaka, M.; Ogata, I. Bull. Chem. Soc. J pn. 1975, 48, 1094.

3
344 Organometallics, Vol. 18, No. 17, 1999
Dakternieks et al.
F igu r e 2. Molecular structure and atomic numbering
scheme for MenPhSnCl
2
(8).
Ta ble 2. Selected In ter a tom ic (Å, d eg) P a r a m eter s
for Men P h Sn Cl (8)
2
Sn-Cl(1)
Sn-C(1)
2.378(3)
2.127(9)
Sn-Cl(2)
Sn-C(7)
2.351(3)
2.174(9)
Cl(1)-Sn-C1(2)
Cl(1)-Sn-C(7)
Cl(2)-Sn-C(7)
99.1(1)
103.6(3)
105.1(3)
Cl(1)-Sn-C(1)
Cl(2)-Sn-C(1)
C(1)-Sn-C(7)
101.6(3)
104.5(3)
137.1(4)
widest angle subtended at tin is by the two organic
substituents (131.4(8)°) compared with 115.5(6)° for Br-
(3)-Sn(2)-C(23) in 7b. The narrower range of angles
in 7b suggests that there is reduced steric hindrance
in this molecule. The crystal structure confirms that the
menthyl group was attached to tin with complete
retention of configuration.
F igu r e 1. Molecular structures and atomic numbering
scheme for the two independent molecules of MenPhSnBr
7).
2
(
The reaction of HgCl2 with 1 afforded MenPhSnCl2
8), which also produced crystals suitable for X-ray
Ta ble 1. Selected In ter a tom ic (Å, d eg) P a r a m eter s
for Men P h Sn Br (7)
(
2
structure analysis. The molecular structure of 8 is
shown in Figure 2, and selected geometric parameters
are collected in Table 2. The conformation about the tin
atom is as found about the Sn(1) atom in 7. The
C-Sn-C angle of 137.1(4)° is greater than that found
in 7a and reflects the fact that the Cl-Sn-Cl angle of
99.1(1)° is more acute than the comparable angle of
Sn(1)-Br(1)
Sn(1)-Br(2)
Sn(1)-C(1)
Sn(1)-C(7)
2.489(3)
2.510(3)
2.04(2)
2.15(2)
Sn(2)-Br(3)
Sn(2)-Br(4)
Sn(2)-C(17)
Sn(2)-C(23)
2.486(3)
2.491(3)
2.12(2)
2.20(2)
Br(1)-Sn(1)-Br(2) 105.2(1) Br(3)-Sn(2)-Br(4)
103.6(1)
Br(1)-Sn(1)-C(1)
Br(1)-Sn(1)-C(7)
Br(2)-Sn(1)-C(1)
Br(2)-Sn(1)-C(7)
C(1)-Sn(1)-C(7)
105.6(6) Br(3)-Sn(2)-C(17) 107.2(5)
104.2(6) Br(3)-Sn(2)-C(23) 115.5(6)
103.0(5) Br(4)-Sn(2)-C(17) 103.5(6)
105.2(5) Br(4)-Sn(2)-C(23) 110.8(6)
131.4(8) C(17)-Sn(2)-C(23) 115.0(8)
1
05.2(1)° in 7a .
The monohalogenation of 1 with 1 molar equiv of
iodine afforded MenPh2SnI (4) in a 93% yield. The
addition of potassium fluoride to this organotin iodide
resulted in halide exchange, forming MenPh2SnF (5) in
a 75% yield. Reaction of 4 and 5 with lithium aluminum
hydride resulted in the formation of MenPh2SnH in
Sch em e 2
1
00% and 48% yields, respectively.
We repeated the previously reported synthesis of
5
Men2Ph2Sn and could obtain only a 34% yield of the
optically pure organotin compound. Reaction of up to 3
molar equiv of MenMgCl with Ph2SnCl2 always gave
mixtures of Men2PhSnCl and Men2Ph2Sn (9). Com-
pound 9 was isolated and formed the basis for the
syntheses described in Scheme 3.
Addition of 2 molar equiv of bromine to 1 afforded
MenPhSnBr2 (7) as a red oil in 95% yield, which
solidified as clear crystals on standing. The molecular
structures of the two independent molecules comprising
the asymmetric unit of 7 are shown in Figure 1 and
selected interatomic parameters are listed in Table 1.
The tin atom in each molecule exists in a distorted
tetrahedral geometry defined by a C2Br2 donor set. As
can be seen from the orientation of the molecules in
Figure 1, two distinct conformations about the tin atom
are found in the solid state, and this is reflected in the
spread of angles about the tin atoms. Thus, for 7a , the
Monohalogenation of 9 by the careful addition of 1
molar equiv of iodine gave Men2PhSnI (10) as a yellow
1
19
oil in 95% yield. Compound 10 displayed a single Sn
1
3
NMR chemical shift at 51.95 ppm. The C NMR
spectrum of 10 indicated 16 different carbon chemical
shifts in the menthyl region associated with the 20
different carbon atoms resulting from the two menthyl
groups at the diastereotopic tin center. Reduction of 10
with LiAlH4 in diethyl ether afforded Men2PhSnH (11)
as a clear oil in 95% yield. A doublet was observed in

Organostannanes Derived from (-)-Menthol
Organometallics, Vol. 18, No. 17, 1999 3345
NMR of 12 after storage in a nonairtight jar for 9
months showed negligible decomposition.
Syn th esis of (Men 3Sn )2 (13), Men 3Sn Br (14), a n d
Men 3Sn H (15). To complete the series we undertook
the preparation of Men3SnH, the latter compound
having been previously synthesized from Men3SnCl.5
Interestingly, Men3SnCl was obtained using the same
experimental procedure as that previously described for
1
1
the synthesis of (Men3Sn)2. We obtained only (Men3-
1
1
119
Sn)2, 13, by following this procedure. The Sn NMR
(
20 °C, CHCl3) spectrum of 13 contains a single broad
1
17
peak (W1/2 approx 600 Hz) at δ 21.2, and no
satellites were observed. At -80 °C, the
resonance sharpens considerably (δ 23.2, W1/2 ) 25 Hz),
and
2
Sn
Sn NMR
1
19
1
17
119
117
Sn satellites are clearly visible [J ( Sn- Sn)
144 Hz]. The rotation of the two trimenthyltin moieties
about the tin-tin bond is rapid at room temperature
and becomes slow on the NMR time scale at -80 °C.
Raising the temperature also causes the tin resonance
1
19
117
to sharpen such that at 105 °C the Sn- Sn coupling
is again clearly observed (δ 18.7, J ( Sn-117Sn) 1880
Hz). The smaller coupling value at the higher temper-
ature is consistent with the small increase in the tin-
tin bond length required to allow free rotation.
119
No electrospray mass spectrum could be obtained on
a sample of 13 in acetonitrile. However, addition of a
small amount of dilute hydrochloric acid to a sample of
F igu r e 3. Molecular structure and atomic numbering
scheme for Men Sn(O CCH Cl) (12). Selected geometric
2 2 2 2
1
3 in acetonitrile shows m/z peaks at Men5Sn2 consis-
parameters (primed atoms are related by 2-fold axis): Sn-
O(1) 2.112(2), Sn-O(2) 2.628(3), Sn-C(3) 2.158(3) Å, O(1)-
Sn-O(2) 53.62(8), O(1)-Sn-O(1)′ 84.2(1), O(2)-Sn-O(2)′
tent with the loss of a menthyl group from (Men3Sn)2.
Reaction of 13 with bromine gives Men3SnBr (14),
which in turn is easily reduced by LiAlH4 to give the
corresponding hydride Men3SnH (15).
1
68.5(1), C(3)-Sn-C(3)′ 151.1(2)°.
Sch em e 3
Exp er im en ta l Section
Gen er a l Meth od s. NMR spectra were obtained using a
1
19
J EOL-GX 270 FT NMR spectrometer ( Sn inverse-gated,
1
19
19
Sn proton coupled, and F), referenced to Me
4 3
Sn and CFCl ,
respectively, and a Varian 300 MHz Unity Plus NMR spec-
1
13
trometer ( H and C), referenced to TMS.
Uncorrected melting points were determined on a Kofler hot
stage. Microanalyses were performed at the Australian Na-
tional University (Canberra, Australia). Electrospray mass
spectra were obtained on a Micromass (VG) Platform mass
spectrometer. High-resolution electrospray mass spectra were
obtained on a Bruker BioApex 47e FT mass spectrometer. All
solvents and reagents used were of analytical reagent grade.
Reactions were generally carried out in an atmosphere of dry
nitrogen. (1R,2S,5R)-menthyl chloride was prepared by the
1
19
1
the
(
Sn NMR spectrum of 11 at -100.1 ppm [ J -
1
19
1
Sn- H) 1564 Hz].
Reaction of 2 molar equiv of chloroacetic acid with
Men2Ph2Sn (9) afforded Men2Sn(O2CCH2Cl)2 (12) as
white crystals in 40% yield. The molecular structure of
1
2 is shown in Figure 3, and selected interatomic
reaction of Lucas reagent with (1R,2S,5R)-menthol as previ-
parameters are listed in the figure caption. The molecule
has 2-fold symmetry and the menthyl substituents have
the R configuration at C-1, indicating retention of
configuration at the reaction center. The tin atom exists
in a skew-trapezoidal bipyramidal geometry with the
menthyl groups disposed over the weaker Sn-O(2)
bonds. The coordination geometry reported here for 12
ously reported.17
Men P h Sn (1). A solution of Ph SnCl (42.0 g, 109.0 mmol)
3
3
3
and Ph P (4.5 g, 17.2 mmol) in THF (150 mL) was added to a
solution of MenMgCl (prepared from magnesium (4.58 g, 188.4
mmol) and (1R,2S,5R)-menthyl chloride (29.9 g, 171.0 mmol)
in THF (100 mL) at room temperature). The reaction mixture
was stirred at room temperature for 1.5 h and then heated at
reflux for a further 30 min. The reaction mixture was
hydrolyzed with 2 M hydrochloric acid (5 mL) and extracted
1
4,15
is as found in related R2Sn(O2CR′)2 systems
with
the noteworthy feature being the magnitude of the
C-Sn-C angle (151.1(2)°), which is wider than is
usually found. The diorganotin dicarboxylates are readily
hydrolyzed to tetraorganodistannoxanes (R′CO2)R2-
with CH
2
Cl
2
(200 mL), the extract was washed with water
), and the solvent was removed
(2 × 100 mL) and dried (MgSO
4
in vacuo. Approximately 60 mL of hexane and 40 mL of
dicloromethane were added to the residue and subsequently
1
6
119
SnOSnR2(OCOR′) and (R′CO2)R2SnOSnR2(OH).
A
Sn
concentrated to 30 mL, at which time most of the Ph
crystallized and was removed by filtration. The remaining
Ph P was converted to Ph PO by the addition of tert-butylhy-
3
P
3
3
(
(
(
14) Tiekink, E. R. T. Appl. Organomet. Chem. 1991, 5, 1.
15) Tiekink, E. R. T. Trends Organomet. Chem. 1994, 1, 71.
16) Davies, A. Organotin Chemistry; VCH: New York, 1997.
(17) Smith, J . G.; Wright, G. F. J . Org. Chem. 1952, 17, 1116-1121.

3
346 Organometallics, Vol. 18, No. 17, 1999
Dakternieks et al.
droperoxide (15 mL) to the above solution. After stirring for
5 min, 1 mL of water was added. The Ph PO was removed
by column chromatography (silica gel 60, 70-230 mesh)
Men
2
P h
2
Sn (9). A solution of Ph
2
SnCl
2
(7.40 g, 36.88 mmol)
1
3
in THF (15 mL) was added to a solution of MenMgCl (prepared
from Mg (3.0 g, 110.6 mmol) and menthyl chloride (19.40 g,
111.1 mmol in THF (20 mL)) and the mixture stirred at room
temperature for 44 h. Water (50 mL) was added, and the
resultant mixture was extracted with ether (3 × 50 mL). The
(
hexane/dichloromethane (80:20)) to give 1 as a clear oil: yield
1
(39.14 g, 73%). H NMR (CDCl
3
): δ 0.90-1.88 (19H, m), 7.47-
): δ 16.0, 21.9, 22.6, 26.9, 34.3,
5.4, 35.6, 35.9 [J ( C- Sn) 436 Hz], 41.7, 46.6, 35.9 128.4,
1
3
7
3
1
.72 (15H, m). C NMR (CDCl
3
1
3
119
4
combined extracts were dried (MgSO ) and the solvent re-
1
3
-19
119
28.7, 137.4, 139.7 [J ( C- Sn) 447 Hz]. Sn NMR (CHCl
3
):
moved in vacuo. The residue was purified by column chroma-
δ -111.4. Anal. Calcd for C28
C, 68.3; H, 7.2.
H
34Sn: C, 68.7; H, 7.0. Found:
tography (silica gel 60, 230-400 mesh) using hexane/dichlo-
romethane (97:3) as the eluent (R
f
0.46). Removal of solvent
left a colorless oil (6.96 g, 34% which was crystallized from
Men P h
CHCl (1.2 L) was added to a solution of 1 (40.5 g, 82.7 mmol)
in CHCl (250 mL) at 0 °C over 6 h. Removal of solvent in
vacuo left a yellow oil (41.5 g, 93%) of sufficient purity for
2
Sn I (4). A solution of iodine (21.0 g, 82.8 mmol) in
1
acetone to afford 9 (4.41 g, 22%), mp 75 °C. H NMR (CDCl
δ 0.79-2.23 (38H, m) 7.40-7.68 (10H, m). 13C NMR (CDCl
3
3
):
):
3
3
1
3
119
δ 16.4, 21.9, 22.6, 26.9, 33.9, 35.1, 35.3, 35.8 [J ( C- Sn) 382
1
3
119
1
Hz], 41.3, 46.2, 127.87, 127.94, 137.5, 141.3 [J ( C- Sn) 382
further use. H NMR (CDCl
3
): δ 0.73-2.34 (19H, m); 7.39-
.79 (10H, m). C NMR (CDCl ): δ 15.8, 21.8, 22.4, 26.6, 34.6,
5.0, 35.3, 40.5 [J ( C- Sn) 430 Hz], 41.2, 46.5, 128.8, 129.6,
Hz]. 1 Sn NMR (CHCl ): δ -89.8. Anal. Calcd for C H48Sn:
19
1
3
7
3
1
3
3
32
1
3
119
119
C, 69.7; H, 8.8. Found: C, 69.8; H, 8.9.
1
3
119
36.3, 138.5 [J ( C- Sn) 444 Hz].
Sn NMR (CHCl
3
): δ
Men
in CHCl
mmol) in CHCl
solvent in vacuo yielded 10 as a yellow oil (5.63 g, 95%). H
2
P h Sn I (10). A solution of iodine (2.50 g, 9.85 mmol)
(500 mL) was added to a solution of 9 (5.43 g, 9.85
(20 mL) at 0 °C over 8 h. Removal of the
-
37.4.
3
2
Men P h Sn F (5). A mixture of KF (4.5 g, 76.9 mmol) in
3
1
water (30 mL) was added to a solution of 4 (25.2 g, 46.8 mmol)
in acetonitrile (50 mL) and the mixture stirred at room
temperature for 2 h. The white precipitate that formed was
collected by filtration to afford 5 of sufficient purity for further
1
3
NMR (CDCl
NMR (CDCl
3
3
): δ 0.11-2.22 (38H, m), 7.27-7.63 (5H, m).
C
3
): δ 16.2, 16.3, 21.9, 22.0, 22.4, 26.7, 34.5, 34.9,
1
3
119
5.0, 35.1, 35.26, 35.31, 41.3, 41.8 [J ( C- Sn) 350 Hz], 42.0,
13 119
1
42.2 [J ( C- Sn) 350 Hz], 46.2, 46.6, 128.4, 128.8, 136.6,
use (26.9 g, 75%), mp > 230 °C. H NMR (DMSO-d ): δ 0.20-
6
13 119 119
2
1
.06 (19H, m), 7.27-7.64 (10H, m). 13C NMR (DMSO-d
5.7, 21.9, 22.7, 25.9, 32.6, 34.8, 35.0, 40.0, 44.1 [d, J ( C-
Sn) 664 Hz, J ( C- F) 5.2 Hz], 44.3, 128.0, 128.5, 135.9,
36.3, 145.3 [d, J ( C- F) 16 Hz] [J ( C- Sn) 657 Hz], 146.1
6
1
): δ
139.6 [J ( C-
Sn) 340 Hz]. Sn NMR (CHCl ): δ 52.0. Anal.
Calcd for C H43SnI: C, 51.9; H, 7.2. Found: C, 52.5; H, 6.9.
3
3
26
1
19
2
13
19
Men
2
P h Sn H (11). A solution of 10 (1.27 g, 2.11 mmol) in
(0.18 g, 4.75
1
3
19
13
119
1
[
ether (5 mL) was added to a suspension of LiAlH
4
1
3
19
13
119
119
d, J ( C- F) 14 Hz] [J ( C- Sn 657 Hz]. Sn (DMSO-d
6
):
): δ
29SnF: C, 61.3; H, 6.8. Found:
mmol) in ether (1 mL) at 0 °C. The reaction mixture was
stirred at room temperature for 15 h, the solids were filtered
off, and the solvent was removed in vacuo to afford 11 as a
1
19
19
19
δ -202.8 [d, J ( Sn- F) 2133 Hz]. F NMR (CHCl
226.5. Anal. Calcd for C22
C, 61.0; H, 7.2.
Men P h Sn H (6). Solid 5 (0.063 g, 0.15 mmol) was added
to a suspension of LiAlH (0.10 g, 0.26 mmol) in ether (30 mL),
3
-
H
1
colorless oil (0.95 g, 95%). H NMR (CDCl
3
): δ 0.87-2.26 (38H,
1
119
13
m), 6.05 (1H, s, J ( H- Sn) 1564 Hz), 7.21-7.71 (5H, m).
NMR (CDCl ): δ 16.0, 16.1, 22.1, 22.2, 22.68, 22.72, 27.1, 34.1,
C
2
3
4
1
3
119
13
119
3
4.3, 35.1 [J ( C- Sn) 385 Hz], 35.3 [J ( C- Sn) 385 Hz],
119
and the mixture was stirred at room temperature for 28 h.
Water (0.25 mL) was added, the solids were filtered off, and
the solvent was removed in vacuo to give 6 as a colorless oil
3
5.7, 42.8, 42.8, 47.4, 47.5, 128.5, 128.6, 138.1, 140.6.
Sn
NMR (C
6
D
6
): δ -100.1 (d, J (1 Sn- H) 1566 Hz]. HRMS
19
1
+
1
(ESI): Calcd for C H Sn (M - H ): 475.2376. Found:
(
0.03 g, 48%). H NMR (C
6
D
6
): δ 0.70-2.12 (19H, m), 6.46 (1H,
26 43
1
119
13
475.2398.
s, J ( H- Sn) 1730 Hz), 7.00-7.60 (10H, m). C NMR
): δ 15.5, 21.6, 22.2, 26.6, 33.9, 34.6 [J ( C- Sn) 432
Hz], 35.2, 35.3, 41.8, 46.7, 128.8, 128.9, 137.8, 138.7.
): δ -133.5 [d, J ( Sn- H) 1743 Hz]. HRMS
ESI): m/z (M - H) Calcd for C22
1
3
119
(
C
6
D
6
2 2 2 2
Men Sn (O CCH Cl) (12). A mixture of 9 (2.90 g, 5.26
1
19
Sn
mmol) and chloroacetic acid (0.99 g, 10.52 mmol) was heated
to 160 °C with stirring for 20 min. The reaction mixture was
allowed to cool and hexane (10 mL) added. The solution was
heated at reflux for 30 min and then allowed to cool to room
1
19
1
NMR (C
(
4
6
D
6
+
H
29Sn: 413.1298. Found:
13.1284.
temperature, after which crystals formed (0.73 g, 38%), mp
Men P h Sn Br
2
(7). Bromine (4.28 g, 26.80 mmol) in meth-
1
1
(
21-123 °C. H NMR (CDCl
3
): δ 0.79-2.58 (38H, m), 4.14
anol (8 mL) was added to a solution of 1 (6.59 g, 13.40 mmol)
in chloroform (50 mL), over 5 min. The solution was stirred
at room temperature for 24 h. The solvent was removed in
vacuo to yield a red oil, which crystallized on standing to give
(6.30 g, 95%), mp 52-53°C. H NMR (CDCl
4H, s). 13C NMR (CDCl
): δ 15.5, 21.7, 22.1, 26.4, 34.2, 34.8,
3
1
3
119
119
3
5.3, 38.3, 40.8, 44.9, 53.5 [J ( C- Sn) 471 Hz], 176.2. Sn
): δ -180.4. Anal. Calcd for C24 Cl : C, 49.3;
H, 7.3. Found: C, 49.3; H, 7.3.
(Men Sn ) (13). A solution of MenMgCl (0.71 M), prepared
from magnesium (9.35 g, 385 mmol) and 1 (60.85 g, 384 mmol)
in THF (250 mL) was added to a solution of SnCl (4.18 mL,
(CDCl
3
H
42SnO
4
2
1
7
(
2
3
), δ 0.83-2.66
): δ 15.5, 21.6,
1
3
19H, m), 7.50-7.79 (5H, m). C NMR (CDCl
3
1
3
2
3
119
2.2, 26.4, 34.4, 35.1, 35.4, 39.4, 45.9, 50.1 [J ( C- Sn) 480
13 119
Hz], 129.2, 130.9, 134.4, 140.6; 140.6 [J ( C- Sn) 518 Hz.
4
1
19
Sn NMR (CHCl
8.8; H, 4.9. Found: C, 38.4; H, 5.1.
Men P h Sn Cl (8). A solution of HgCl
in acetone (250 mL) was added slowly to a solution of 1 (9.41
g, 19.2 mmol) in acetone (50 mL) at 0 °C, after which the
reaction mixture was stirred at room temperature for 18 h.
The solvent was removed in vacuo and the PhHgCl removed
by precipitation from chloroform/hexane to afford crude 8 as
a colorless oil (6.49 g, 72%). A sample of the crude product
was crystallized from hexane to give pure 8 as colorless
3
): δ 4.7. Anal. Calcd for C16
H
24SnBr
2
: C,
35.70 mmol) in benzene (20 mL). The reaction mixture was
heated at reflux for 5 h and stirred at room temperature for a
further 16 h. The reaction was quenched with 10% hydrochlo-
ric acid (10 mL) and water (200 mL). The mixture was
extracted with ether (4 × 50 mL), the combined extracts were
3
2
2
(9.91 g, 36.5 mmol)
4
dried (MgSO ), and the solvent was removed in vacuo. The
residue was recrystallized from ethanol to afford 13 as a white
1
solid (19.27 g, 50%), mp > 280 °C. H NMR (CDCl
3
): δ 0.82-
.23 (114H, m). 13C NMR (CDCl
): 17.4, 22.2, 22.5, 27.7, 34.5,
3
2
3
1
3
119
119
5.7, 36.6, 39.6 [J ( C- Sn) 427 Hz], 45.6, 46.4. Sn NMR
1
19
1
(CDCl ): δ 21.2 (W approx 600 Hz) (cf. 18.8, ref 11). Sn
crystals, mp 71-73 °C. H NMR (CDCl
m), 7.44-7.68 (5H, m). C NMR (CDCl
3
): δ 0.83-2.69 (19H,
): δ 15.5, 21.65, 22.2,
3
1/2
1
19
117
119
1
3
NMR (hexane, -80 °C): δ 23.2 [J (1 Sn- Sn) 2144 Hz]. Sn
3
19 117
1
3
119
NMR (toluene, 105 °C): δ 18.7 [J ( Sn- Sn) 1880 Hz]. Anal.
2
1
(
6.4, 34.4, 35.2, 36.1, 38.7, 45.6, 50.4 [J ( C- Sn) 516 Hz],
13 119 119
Calcd for C H Sn : C, 67.2; H, 10.7. Found: C, 67.1; H, 11.1.
60 114
2
29.4, 131.1, 134.5, 140.7 [J ( C- Sn) 565 Hz]. Sn NMR
): δ 26.8. Anal. Calcd for C16 24SnCl : C, 47.3; H, 6.0.
Found: C, 47.6; H, 6.2.
CDCl
3
H
2
Men
3
Sn Br (14). A solution of bromine (0.45 g, 2.82 mmol)
in benzene (20 mL) was added to a solution of 13 (3.00 g, 2.80

Organostannanes Derived from (-)-Menthol
Organometallics, Vol. 18, No. 17, 1999 3347
1
Ta ble 3. Cr ysta llogr a p h ic Da ta for Men P h Sn Br
2
crystallized on standing (0.36 g, 80%), mp 25-30 °C. H NMR
1
3
(
7), Men P h Sn Cl
2
(8), a n d Men
2
Sn (O
2
CCH
2
Cl)
2
(12)'
(CDCl
3
): 0.79-2.15 (58H, m), 5.39 (1H, s). C NMR (CDCl ):
3
1
3
119
1
3
1
6.3, 22.4, 23.0, 27.2, 33.8, 34.4 [J ( C- Sn) 338 Hz], 35.8,
19 1
7
8
12
6.0, 43.2, 41.6. 1 Sn NMR (CDCl
456 Hz (cf. -102.9, ref 5).
): -103.12 (d, J (119Sn- H)
3
formula
fw
C16H24Br2Sn
494.9
C16H24Cl2Sn
406.0
C24H42Cl2O4Sn
584.2
Cr ysta l a n d Molecu la r Str u ctu r es of 7, 8, a n d 12.
cryst size, mm
0.016 ×
0.13 ×
0.39 ×
Intensity data were measured on a Rigaku AFC6R diffrac-
tometer fitted with graphite-monochromatized Mo KR radia-
tion, λ ) 0.71073 Å and employing the ω-scan technique. The
data sets were corrected for Lorentz and polarization effects,
and an empirical absorption correction was applied in each
0
.18 × 0.32
0.18 × 0.32
colorless
293
0.39 × 0.65
colorless
293
color
colorless
293
triclinic
P1
9.417(3)
12.846(6)
9.084(4)
98.86(4)
114.94(2)
70.90(3)
941.5(7)
2
temp, K
cryst syst
space group
a, Å
b, Å
c, Å
1
8
orthorhombic orthorhombic
P212121
10.926(7)
18.661(10)
8.824(7)
90
90
90
1799(2)
4
1.499
816
P21212
9.782(5)
17.454(3)
8.350(3)
90
19
case. Relevant crystal data are given in Table 3.
The structures were solved by direct methods employing
2
0
DIRDIF and refined by a full-matrix least-squares procedure
based on F.18 Non-H atoms were refined with anisotropic
displacement parameters, and H atoms were included in the
models in their calculated positions. Absolute configurations
were confirmed by refining the opposite hands, which resulted
R, deg
â, deg
γ, deg
90
90
3
V, Å
1425.5(7)
2
1.361
604
11.08
0.523-1
Z
-
3
Dcalcd, g cm
F(000)
µ, cm
1.746
480
56.02
0.288-1
in a higher value for R
w
in each case. Final refinement details
are collected in Table 3, and the numbering schemes employed
-
1
17.03
0.446-1
2
1
are shown in Figures 1-3, which were drawn with ORTEP
transmission
factors
with 50% probability ellipsoids. The teXsan18 package, in-
stalled on an Iris Indigo workstation, was employed for all
calculations.
no. of data colld
θmax, deg
4592
27.5
2394
27.5
1306
1901
27.5
1706
no. of unique data 1764
with I g 3.0σ(I)
Ack n ow led gm en t. We thank the Australian Re-
search Council for financial support and are grateful for
a Deakin University Postgraduate Award (DUPA) to
K.D.
R
0.046
0.040
0.037
0.036
0.45
0.022
0.025
0.31
Rw
residual electron 0.74
-
3
density, Å
mmol) in benzene (10 mL) at 6 °C with further stirring at room
temperature for 3 h. Removal of the solvent in vacuo and
crystallization from ethanol afforded 14 as a white solid (1.66
Su p p or tin g In for m a tion Ava ila ble: Further details of
the structure determination including atomic coordinates, bond
distances and angles, and thermal parameters. This material
is available free of charge via the Internet at http://pubs.acs.org.
1
13
g, 96%), mp 137 °C. H NMR (CDCl
3
): 0.82-2.17 (57H, m). C
NMR (CDCl ): δ 16.8, 22.1, 22.6, 27.1, 35.0, 35.2, 35.4, 40.9,
3
1
3
119
119
4
1
3.5 [J ( C- Sn) 292 Hz], 46.4; 43.5. Sn NMR (CDCl
3
): δ
OM990088T
08.6 (cf. 105.5, ref 11). Anal. Calcd for C30 57SnBr: C, 58.5;
H
H, 9.3. Found: C, 58.1; H, 10.0.
Men Sn H (15). A solution of Men
in THF (10 mL) and benzene (5 mL) was added to a suspension
of LiAlH (0.20 g, 5.26 mmol) in THF (5 mL) and the mixture
stirred at room temperature for 30 min. The reaction mixture
was quenched with water (20 mL) and extracted with ether
(
18) teXan Structure Analysis Software; Molecular Structure Cor-
poration: The Woodlands, TX, 1996.
19) Walker, N. Stuart, D. Acta Crystallogr. Sect. A 1983, 39, 158.
3
3
SnBr (0.45 g, 0.73 mmol)
(
4
(20) Beurskens, P. T. A., G.; Beurskens, G.; Bosman, W. P.; Garcia-
Granda, S.; Smits, J . M. M.; Smykalla, C. The DIRDIF Program
System, Technical Report of the Crystallography Laboratory; University
of Nijmegen: The Netherlands, 1992.
(
3 × 20 mL). The combined extracts were dried (MgSO
4
), and
(21) J ohnson, C. K. ORTEP. Report ORNL-5138; Oak Ridge National
the solvent was removed in vacuo to yield a colorless oil which
Laboratory: Oak Ridge, TN, 1976.