Reactions of Sulfanyl Chlorides with Thiocamphor and Thiofenchone: Wagner-Meerwein Rearrangement of an Intermediate Thiocarbonylium Ion

Article abstract of DOI:10.1002/hlca.200490077

The reaction of sulfanyl and disulfanyl chlorides with thiocamphor (6) in the presence of Et₃N leads to unsymmetrical di- and trisulfanes, respectively (Schemes 2 and 4). A reaction mechanism via a thiocarbonylium ion, which is immediately deprotonated, is proposed. The formation of a minor product 10 in the absence of a base, resulting from a Wagner-Meerwein rearrangement, is an additional evidence for the intermediacy of a thiocarbonylium ion (Scheme 3). On the other hand, the non-enolizable thiofenchone (13) reacts with sulfanyl chlorides in CH₂Cl ₂/Et₃N to give exclusively products with a rearranged bicyclic skeleton (Scheme 5). A Wagner-Meerwein rearrangement of the intermediate thiocarbonylium ion is the key step. The structures of the products 10 and 14, which have rearranged bicyclic systems, have been established by X-ray crystallography.

Full text of DOI:10.1002/hlca.200490077

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Helvetica Chimica Acta Vol. 87 (2004)
Reactions of Sulfanyl Chlorides with Thiocamphor and Thiofenchone:
WagnerÀMeerwein Rearrangement of an Intermediate Thiocarbonylium Ion
by Agnieszka Majchrzaka)1), Grzegorz Mloston¬*b), Anthony Lindena), and Heinz Heimgartner*a)
a) Organisch-chemisches Institut der Universit‰t Z¸rich, Winterthurerstrasse 190, CH-8057 Z¸rich
b
¬
¬
¬
¬
) Section of Heteroorganic Compounds, University of Ëodz, Narutowicza 68, PL-90-136 Ëodz
The reaction of sulfanyl and disulfanyl chlorides with thiocamphor (6) in the presence of Et3N leads to
unsymmetrical di- and trisulfanes, respectively (Schemes 2 and 4). A reaction mechanism via a thiocarbonylium
ion, which is immediately deprotonated, is proposed. The formation of a minor product 10 in the absence of a
base, resulting from a WagnerÀMeerwein rearrangement, is an additional evidence for the intermediacy of a
thiocarbonylium ion (Scheme 3). On the other hand, the non-enolizable thiofenchone (13) reacts with sulfanyl
chlorides in CH2Cl2/Et3N to give exclusively products with a rearranged bicyclic skeleton (Scheme 5). A
WagnerÀMeerwein rearrangement of the intermediate thiocarbonylium ion is the key step. The structures of the
products 10 and 14, which have rearranged bicyclic systems, have been established by X-ray crystallography.
1. Introduction. In a recent report [1], reactions of the sterically crowded 2,2,4,4-
tetramethyl-3-thioxocyclobutanone (1) with PCl5 and SCl2 to give the stable a-
chlorosulfanyl chloride 2 and a-chlorodisulfanyl chloride 3, respectively, have been
described (Scheme 1). These products were shown to add easily to 1 to give
symmetrically substituted polysulfanes 4 [2][3]. On the other hand, 2 and 3 are highly
electrophilic reagents, which react smoothly with enolizable thiocarbonyl-functional-
ized N-heterocycles like 1H-imidazole-2-thiones or thiouracil to give the corresponding
di- and trisulfanes of type 5, respectively [2].
Scheme 1
1
)
Part of the planned Ph.D. thesis of A. M., Universit‰t Z¸rich.

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Sulfur transfer via a thiocarbonylium ion with subsequent hydrolysis was observed
when 2 or 3 were reacted with non-enolizable thiocarbonyl compounds (e.g.,
thiobenzophenone, 4,4-dimethyl-2-phenyl-1,3-thiazole-5(4H)-thione) in wet THF.
The products isolated from these reactions correspond to symmetrical polysulfanes
of type 4, which contain three or five S-atoms [2].
In our ongoing study focused on the application of thiocarbonyl compounds for the
preparation of S-rich molecules, we were interested in reactions of 2 and 3 with
enolizable thioketones. Based on our experience, thiocamphor (6) was selected as an
easily accessible [4], relatively stable, and almost non-odorous substrate. To compare
the reactivity of similarly substituted thioketones, thiofenchone was reacted under
similar conditions.
2. Results and Discussion. 2.1. Reactions with Thiocamphor (6). The reactions of 2
and 3 with thiocamphor (6) in a molar ratio of 1:1 were carried out in abs. CH2Cl2 in the
presence of an equimolar amount of Et3N at room temperature. The color of 6
disappeared within a few min, and, after evaporation of the solvent, the crude products
were analyzed by NMR spectroscopy. The yields of the obtained products (ca. 70%)
1
were determined by H-NMR spectroscopy after addition of a weighed amount of
1,1,2,2-tetrachloroethane as an external standard. In both cases, the NMR spectra
showed a doublet for an olefinic CH group (d(H): 6.24 and 6.33 ppm, resp.; d(C): 153.3
and 139.4 ppm, resp.). Other signals observed in the spectra confirmed the presence of
the bicyclic moiety as well as the substituted cyclobutanone. The CI-MS (NH3)
indicated the molecular formula of the corresponding di- and trisulfane 7 and 8
(Scheme 2). Although the spectroscopic data convincingly established the structures,
all attempts to obtain the products in an analytically pure form were in vain. During
chromatography, both products decomposed, and only unconverted 6, along with small
amounts of the known symmetrical disulfane 9 [5], was isolated.
Scheme 2

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We assumed that the instability of 7 and 8 may be a result of the lability of the CÀCl
bond, but all experiments aimed towards the substitution of the Cl-atom by
nucleophiles such as morpholine and sodium thiophenolate led to complex mixtures
of decomposition products.
The presence of Et3N is crucial for the smooth reaction leading to 7 and 8, as, in its
absence, complex mixtures were formed. In one of the experiments with 2 and 6,
chromatographic workup gave traces of a product 10, which is an isomer of 7. Its
structure was unambiguously determined by X-ray crystallography (Fig. 1).
Fig. 1. ORTEP Plot [6] of the molecular structure of 10 (50% probability ellipsoids, arbitrary numbering of
atoms)
The structure presented in Fig. 1 shows that the bicyclic skeleton corresponds to a
rearranged product formed via a WagnerÀMeerwein rearrangement [7]. It seems that,
in the absence of Et3N, the intermediate thiocarbonylium salt A (n ˆ 1) is not
spontaneously transformed into 7, but undergoes a 1,2-shift to give the carbenium ion B,
which by deprotonation yields 10 (Scheme 3).
The results obtained with a-chlorosulfanyl chloride 2 prompted us to carry out
similar reactions with the commercially available (nitrophenyl)sulfanyl chlorides 11a
1
and 11b. The progress of the conversions was monitored by H-NMR spectroscopy.
Both sulfanyl chlorides reacted with 6 much more slowly than 2 and 3 and, in the case of
11a, even after 72 h, 12% of 6 were still recovered (Table 1). Therefore, the reactions
were repeated at 1008 in CCl4/toluene solution. After 3 h heating and chromatographic
workup, the corresponding disulfanes 12a and 12b were isolated in 57 and 42% yield,
respectively (Scheme 4). Unlike the analogous products 7 and 8, no decomposition was
observed during isolation and purification.
2.2. Reactions with Thiofenchone (13). The reactions of 13 with sulfanyl chlorides
were carried out under analogous conditions to those described for 6 (Sect. 2.1).
Whereas, in the case of 2, the reaction was complete after 2 min, 24 h were necessary in
the case of 3. The crude products 14 and 15 (Scheme 5) were analyzed by NMR

Helvetica Chimica Acta Vol. 87 (2004)
793
Scheme 3
Scheme 4
Table 1. Reactions of 6 with (Nitrophenyl)sulfanyl Chlorides 11 in CH2Cl2
11
Temp. [8]
Time [h]
12 [%]
9 [%]
6 [%]
a 4-NO2
r.t.
r.t.
1
72
3
1
3
13
32
57
59
42
17
29
traces
3
traces
69
12
2
4
25
1008a)
r.t.
b 2-NO2
1008a)
a) Reaction carried out in CCl4/toluene 1 : 1.
spectroscopy. The products obtained in the two experiments showed triplet-like signals
for two H-atoms at d 5.24/4.88 and 5.18/4.89 ppm with J ˆ 1.9 2.4 Hz, respectively. This
pattern is characteristic for the olefinic CH2 group. In the 13C-NMR spectra, the
corresponding signals of 14 appeared at d 154.2 (s) and 106.2 (t) ppm, and at 153.2 (s)
and 106.4 (t) in the case of 15. The other signals in the NMR spectra showed that both
products have similar structures, and the CI-MS confirmed that they differ by only one
S-atom.

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Scheme 5
All these data indicated that the formation of 14 and 15 occurred via rearrangement
of the bicyclic skeleton in a manner, which corresponds to a WagnerÀMeerwein
rearrangement. In the case of 14, the product was obtained in crystalline form, and its
structure was confirmed by X-ray crystallography (Fig. 2)2).
In contrast to 14, the trisulfane 15 could not be isolated in pure form.
Chromatography on SiO2 plates led to partial decomposition of the main product,
and only a mixture of the known symmetric bis(1-chloro-2,2,4,4-tetramethyl-3-
oxocyclobutyl)tri- and -tetrasulfanes 4 (n ˆ 3,4) [3] was isolated as a minor fraction.
The (nitrophenyl)sulfanyl chlorides 11a and 11b reacted with 13 to give disulfanes
of type 16 via WagnerÀMeerwein rearrangement of the intermediate thiocarbonylium
cation (Scheme 5). Similar to the reaction with 6, longer reaction times than with 2
were needed to complete the reactions.
In conclusion, the results described show that thiocarbonylium cations, formed by
electrophilic addition of sulfanyl chlorides to thioketones, are stabilized by deproto-
nation. Whereas vinylic polysulfanes are formed in the case of the enolizable
thiocamphor (6), the direct deprotonation is not possible in the case of the non-
enolizable thiofenchone (13). In this system, a WagnerÀMeerwein rearrangement
2
)
Repeated recrystallization from hexane gave a single crystal that proved to be racemic, although the solid
obtained after chromatography was optically active (see Exper. Part).

Helvetica Chimica Acta Vol. 87 (2004)
795
Fig. 2. ORTEP Plot [6] of the molecular structure of 14 (50% probability ellipsoids, arbitrary numbering of
atoms)
occurs prior to the deprotonation. The course of this reaction is in accordance with
already described transformations of the in situ generated thiocarbonylium cation
formed by protonation of the transient thiofenchone S-methylide [8][9].
We thank the analytical units of the Institute of Organic Chemistry of the University of Z¸rich for spectra
and analyses. Financial support of this work by the Swiss NationalScience Foundation and F. Hoffmann-La
Roche AG, Basel, is gratefully acknowledged. G. M. acknowledges financial support by the Polish State
Committee for Scientific Research (grant No. 4 T09A 046 25).
Experimental Part
1. General. See [2]. M.p.: Mettler FP-5 or B¸chi B-450 apparatus; uncorrected. IR Spectra: Perkin-Elmer
781 or Perkin-Elmer 1600-FT-IR spectrophotometer. 1H- and 13C-NMR spectra: Bruker AC 300 or Bruker ARX-
300 instrument (300 and 75.5 MHz, resp.), or Bruker DRX-600 instrument (600 and 150.9 MHz, resp.), in
CDCl3. MS: Finnigan MAT-90 or Finnigan SSQ-700 instrument (EI, 70 eV, or CI (NH3)). Elemental analyses
were performed by the Mikroanalytisches Laboratorium des Organisch-chemischen Instituts der Universit‰t
Z¸rich.
2. Starting Materials. (À)-(1R,4R)-1,7,7-Trimethylbicyclo[2.2.1]heptane-2-thione (ˆthiocamphor; 6) and
(À)-(1R,4S)-1,3,3-Trimethylbicyclo[2.2.1]heptane-2-thione (thiofenchone; 13) were prepared according to [4] by
treatment of a soln. of the corresponding ketones in MeOH with a mixture of HCl and H2S gas in the presence of
equal amounts of methyl orthoformate. 3-Chloro-3-(chlorosulfanyl)-2,2,4,4-tetramethylcyclobutanone (2) and 3-
chloro-3-(chlorodisulfanyl)-2,2,4,4-tetramethylcyclobutanone (3) were obtained from 2,2,4,4-tetramethyl-3-
thioxocyclobutanone according to a protocol described in [1]. The (4-nitrophenyl)- and (2-nitrophenyl)sulfanyl
chlorides (11a and 11b, resp.) are commercially available (Aldrich).
3. Reactions of 6 with Sulfanyl Chlorides. GeneralProcedure . To a soln. of 6 (84.5 mg, 0.5 mmol) and Et3N
(50.6 mg, 0.5 mmol) in CH2Cl2 (3 ml) at r.t. was added a soln. of the corresponding sulfanyl chloride (0.5 mmol)
in CH2Cl2 (2 ml). The color of the soln. changed significantly. After the indicated time, the solvent was
evaporated, and the residue was triturated with Et2O and filtered to remove the inorg. salts. The solvent was
again evaporated, the residue was dissolved in CDCl3, and the yield of the product was determined by 1H-NMR
spectroscopy with respect to a weighed amount of 1,1,2,2-tetrachloroethane as an external standard.

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3.1. Reaction with 2. Reaction time 2 min. Color change from orange to yellow. Yield (1H-NMR): 74% of 3-
chloro-2,2,4,4-tetramethyl-3-{2-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-en-2-yl]disulfanyl}cyclobutanone
1
(7). H-NMR: 6.24 (d, J ˆ 3.4, HÀC(3')); 2.39 (t, J ˆ 3.5, 1 H); 1.94 1.82 (m, 1 H); 1.61 1.51 (m, 1 H); 1.50,
1.47, 1.42, 1.41 (4s, 4 Me); 1.24 1.12 (m, 1 H); 1.07 (s, Me); 1.06 0.95 (m, 1 H); 0.84, 0.79 (2s, 2 Me). 13C-NMR:
216.7 (s, C(1)); 141.2 (s, C(2')); 135.3 (d, C(3')); 88.1 (s, C(3)); 69.4 (s, C(2), C(4)); 57.6 (s, C(1')); 56.6 (s, C(7'));
52.4 (d, C(4')); 31.5 (t, C(6')); 25.4 (t, C(5')); 23.5, 23.1, 22.6, 22.3 (4q, 2 MeÀC(2), 2 MeÀC(4)); 19.5, 19.3
‡
‡
(2q, 2 MeÀC(7')); 11.4 (q, MeÀC(1')). CI-MS (NH3): 361 (10), 359 (88, [M ‡ 1] ), 323 (100, [M À Cl] ), 169
(7).
An analogous reaction was carried out in the absence of Et3N. After stirring the mixture for 1 h (orange !
yellow), the solvent was evaporated, and the residue was separated by prep. TLC (hexane/Et2O 15 :1): ca. 9 mg
(5%) of 3-chloro-2,2,4,4-tetramethyl-3-{[(1R,4R)-3,3-dimethyl-2-methylidenebicyclo[2.2.1]hept-1-yl]disulfa-
nyl}cyclobutanone (10). Colorless crystals. M.p. 86.9 87.18 (hexane). Single crystals suitable for an X-ray
crystal-structure determination were grown from hexane.
3.2. Reaction with 3. Reaction time: 2 min. Color change from orange to yellow. Yield (1H-NMR): 62% of
3-chloro-2,2,4,4-tetramethyl-3-{3-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-en-2-yl]trisulfanyl}cyclobutanone
(8). 1H-NMR: 6.33 (d, J ˆ 3.4, HÀC(3')); 2.44 (t, J ˆ 3.6, 1 H); 1.93 1.88 (m, 1 H); 1.61 1.50 (m, 1 H); 1.46
(s, 2 Me); 1.43 (s, 2 Me); 1.18 1.13 ( m, 1 H); 1.11 (s, Me); 1.07 1.00 (m, 1 H); 0.84, 0.81 (2s, 2 Me). 13C-NMR:
216.2 (s, C(1)); 141.6 (s, C(2')); 139.4 (d, C(3')); 87.6 (s, C(3)); 69.0 (s, C(2), C(4)); 57.3 (s, C(1')); 56.8( s, C(7'));
52.7 (d, C(4')); 31.6 (t, C(6')); 25.2 (t, C(5')); 23.6, 23.3, 22.9, 22.3 (4q, 2 MeÀC(2), 2 MeÀC(4)); 19.6, 19.3
‡
(2q, 2 MeÀC(7')); 11.7 (q, MeÀC(1')). CI-MS (NH3): 457 (19), 455 (33), 391 (40, [M ‡ 1] ), 365 (16), 359 (52),
‡
‡
355 (100, [M À Cl] ), 335 (23), 323 (61), 169 (44, [C10H16S ‡ 1] ).
3.3. Reaction with 11a. Reaction time: 1 h and 3 d at r.t., and 3 h at 1008 (CCl4/toluene 1 :1) (see Table 1).
Color change from brown to orange. The mixture was separated by prep. TLC (hexane/Et2O 20 :1) to yield
21 mg (13%), 51 mg (32%), and 91 mg (57%), resp., of 1-(4-nitrophenyl)-2-[(1R,4R)-1,7,7-trimethylbicy-
23
D
clo[2.2.1]hept-2-en-2-yl]disulfane (12a). Pale yellow crystals. M.p. 93 958 (hexane). ‰aŠ ˆ À170.9 (c ˆ 1.1,
CHCl3). IR (KBr): 2951m, 1593m, 1577m, 1511s, 1473m, 1362m, 1336s, 1176w, 1105m, 1078w, 8 51m, 8 38m, 794w,
741m, 710w, 68 0w. 1H-NMR: 8.09, 7.52 (AA'BB', J ˆ 9.0, 4 arom. H); 6.00 (d, J ˆ 3.4, HÀC(3)); 2.29 (t, J ˆ 3.5,
HÀC(4)); 1.85 1.76 (m, 1 H); 1.60 1.47 (m, 1 H); 1.09 1.03 (m, 1 H); 1.05 (s, Me); 1.02 0.82 (m, 1 H); 0.71,
0.63 (2s, 2 Me). 13C-NMR: 145.6, 145.2, 139.4 (3s, 2 arom. C, C(2)); 134.7 (d, C(3)); 125.2, 122.9 (2d, 4 arom.
CH); 56.5 (s, C(1)); 56.2 (s, C(7)); 51.4 (d, C(4)); 30.7 (t, C(6)); 24.5 (t, C(5)); 18.5, 18.3 (2q, 2 MeÀC(7)); 10.4
‡
‡
(q, MeÀC(1)). CI-MS: 322 (100, [M ‡ 1] ), 169 (16, [C10H16S ‡ 1] ). Anal. calc. for C16H19NO2S2 (321.46): C
59.78, H 5.96, N 4.36, S 19.95; found: C 59.76, H 6.19, N 4.31, S 19.71.
3.4. Reaction with 11b. Reaction time: 1 h at r.t. and 3 h at 1008 (CCl4/toluene 1:1), (see Table 1). Color
change from brown to orange. The mixture was separated by prep. TLC (hexane/Et2O 20 :1) to yield 94 mg
(59%) and 68mg (42%), resp., of 1-(2-nitrophenyl)-2-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]hept-2-en-2-
23
yl]disulfane (12b). Yellow oil. ‰aŠ ˆ À30.9 (c ˆ 0.9, CHCl3). IR (film): 2952m, 1590m, 1567m, 1513s, 1449m,
D
1
1304m, 1101w, 1039m, 8 52m, 728m, 732s, 710m, 68 1w, 653w. H-NMR: 8.17 (dd, J ˆ 9.6, 1.3, 1 arom. H); 8.00
(dd, J ˆ 9.4, 1.2, 1 arom. H); 7.57 7.52, 7.28 7.22 (2 m, 2 arom. H); 5.88 (d, J ˆ 3.4, HÀC(3)); 2.25 (t, J ˆ 3.5,
HÀC(4)); 1.82 1.73, 1.54 1.46, 1.09 1.05 (3m, 3 H); 1.07 (s, Me); 1.03 0.83 (m, 1 H); 0.70, 0.68(2 s, 2 Me).
13C-NMR: 144.7, 139.4, 136.1 (3s, 2 arom. C, C(2)); 132.8, 132.7 (2d, 2 arom. C); 126.5 (d, C(3)); 125.0, 124.9
(2d, 2 arom. C); 56.4, 56.2 (2s, C(1), C(7)); 51.3 (d, C(4)); 30.6, 24.6 (2t, C(6), C(5)); 18.6, 18.3
‡
‡
(2q, 2 MeÀC(7)); 10.4 (q, MeÀC(1)). CI-MS: 322 (100, [M ‡ 1] ), 169 (18, [C10H16S ‡ 1] ). Anal. calc. for
C16H19NO2S2 (321.46): C 59.78, H 5.96, N 4.36, S 19.95; found: C 59.64, H 6.16, N 4.13, S 19.90.
4. Reactions of 13 with Sulfanyl Chlorides. According to the GeneralProcedure . 4.1. Reaction with 2.
Reaction time: 2 min. Color change from orange to colorless. Prep. TLC (hexane/Et2O 15 :1) gave 96 mg (54%)
of 3-chloro-3-{2-[(1S,4S)-7,7-dimethyl-2-methylidenebicyclo[2.2.1]hept-1-yl]disulfanyl}-2,2,4,4-tetramethylcy-
clobutanone (14) as a colorless oil. After recrystallization from hexane, 14 mg (8%) of 14 were obtained as
23
D
colorless crystals. M.p. 73 758 (hexane). ‰aŠ ˆ À143.6 (c ˆ 1, AcOEt). IR (KBr): 2995w, 2956m, 2936m,
2873w, 1788vs, 1768m, 1656w, 1465m, 1454w, 1384m, 1367w, 1171w, 1027w, 977w, 915w, 8 8w7, 8 31w, 699w.
1H-NMR (600 MHz, C6D6): 5.24 (t-like, J ꢀ 2.2, 1 H of ˆCH2); 4.88 (t-like, J ꢀ 1.9, 1 H of ˆCH2); 2.51 2.45
(m, HexoÀC(6'), HexoÀC(3')); 2.06 (dt, J ˆ 16.1, 1.8, HendoÀC(6')); 1.95 1.89 (m, HexoÀC(5')); 1.84 (t, J ˆ 3.4,
HÀC(4')); 1.70 1.64 (m, HendoÀC(3')); 1.57, 1.47 (2s, MeÀC(2), MeÀC(4)); 1.41 (s, MeÀC(2), MeÀC(4));
1.39 1.32 (m, HendoÀC(5')); 0.98, 0.84 (2s, 2 MeÀC(7')). 13C-NMR (150.9 MHz, C6D6): 217.0 (s, C(1)); 154.2
(s, C(2')); 106.2 (t, ˆCH2); 86.1 (s, C(3)); 70.4, 68.1 (2s, C(2), C(4)); 66.5 (s, C(1')); 50.5 (s, C(7')); 43.7
(d, C(4')); 37.1 (t, C(6')); 33.8( t, C(3')); 28.0 (t, C(5')); 23.8, 23.7, 23.6, 21.8 (4q, 2 MeÀC(2), 2 MeÀC(4)); 19.6,

Helvetica Chimica Acta Vol. 87 (2004)
797
‡
‡
19.4 (2q, 2 MeÀC(7')). CI-MS (NH3): 325 (13), 324 (21), 323 (100, [M À Cl] ), 169 (17, [C10H16S ‡ 1] ). Anal.
calc. for C18H27ClOS2 (358.99): C 60.22, H 7.57, S 17.86; found: C 60.67, H 7.95, S 17.84.
Single crystals suitable for an X-ray crystal-structure determination were grown from hexane.
4.2. Reaction with 3. Reaction time: 24 h. No color change. Yield (1H-NMR): 28% of 3-chloro-3-{3-
[(1S,4S)-7,7-dimethyl-2-methylidenebicyclo[2.2.1]hept-1-yl]trisulfanyl}-2,2,4,4-tetramethylcyclobutanone (15).
1H-NMR (600 MHz, C6D6): 5.18( t-like, J ꢀ 2.4, 1 H of ˆCH2); 4.89 (t, J ꢀ 2.0, 1 H of ˆCH2); 2.52 2.45
(m, 2 H); 2.08 1.66 ( m, 4 H); 1.57, 1.46, 1.43, 1.41 (4s, 2 MeÀC(2), 2 MeÀC(4)); 1.40 1.33 (m, 1 H); 1.07, 0.89
(2s, 2 MeÀC(7')). 13C-NMR (150.9 MHz, C6D6): 217.6 (s, C(1)); 153.2 (s, C(2')); 106.4 (t, ˆCH2); 87.4 (s, C(3));
71.0, 69.2 (s, C(2), C(4)); 67.0 (s, C(1')); 50.3 (s, C(7')); 44.5 (d, C(4')); 37.0 (t, C(6')); 34.6 (t, C(3')); 28.1
(t, C(5')); 23.4, 23.1, 23.0, 22.4 (4q, 2 MeÀC(2), 2 MeÀC(4)); 20.0, 19.6 (2q, 2 MeÀC(7')). CI-MS (NH3): 367
‡
‡
(5), 355 (19, [M À Cl] ), 327 (12), 323 (100), 201 (9), 199 (20), 169 (66, [C10H16S ‡ 1] ), 167 (5).
4.3. Reaction with 11a. Reaction time: 1 h. Color change from brown to orange. The mixture was separated
by prep. TLC (hexane/Et2O 20 :1) to yield 51 mg (32%) of 1-[(1S,4S)-7,7-dimethyl-2-methylidenebicyclo[2.2.1]-
hept-1-yl]-2-(4-nitrophenyl)disulfane (16a)3) and 27 mg (32%) of 13.
23
D
Data of 16a: Yellow oil. ‰aŠ ˆ À163.1 (c ˆ 0.9, CHCl3). IR (film): 2947m, 1596w, 1577m, 1513s, 1474m,
1367w, 1334s, 1108m, 1075m, 1009w, 977w, 8 8 5w, 8 51m, 757w, 741m, 681w. 1H-NMR: 8.09, 7.62 (AA'BB', J ˆ 9.1,
4 arom. H); 5.15 (t-like, J ꢀ 2.5, 1 H of ˆCH2); 4.85 (t-like, J ꢀ 2.1, 1 H of ˆCH2); 2.48 2.41 ( m, 1 H); 2.12
1.93 (m, 2 H); 1.83 1.73 (m, 2 H); 1.51 1.38( m, 1 H); 1.26 1.18( m, 1 H); 0.95, 0.82 (2s, 2 Me). 13C-NMR:
152.8( s, C(2)); 147.8, 145.0 (2s, C(1), C(4)); 124.9, 122.8(2 d, 4 arom. CH); 105.1 (t, ˆCH2); 66.7 (s, C(1)); 49.6
(s, C(7)); 42.8( d, C(4)); 35.9 (t, C(6)); 32.5 (t, C(3)); 26.7 (t, C(5)); 18.8, 18.7 (2q, 2 MeÀC(7)). CI-MS (NH3):
‡
‡
‡
340 (20), 339 (100, [M ‡ NH4] , 322 (20, [M ‡ 1] ), 169 (17, [C10H16S ‡ 1] ), 167 (8). Anal. calc. for
C16H19NO2S2 (321.46): C 59.78, H 5.96, N 4.36, S 19.95; found: C 59.94, H 6.01, N 4.15, S 19.70.
4.4. Reaction with 11b. Reaction time: 1 h. Color change from brown to orange. The mixture was separated
by prep. TLC (hexane/Et2O 20 :1) to yield 79 mg (49%) of 1-[(1S,4S)-7,7-dimethyl-2-methylidenebicyclo[2.2.1]-
hept-1-yl]-2-(2-nitrophenyl)disulfane (16b)3) and 4 mg (5%) of 13. Yellow crystals. M.p. 67 698 (hexane).
23
‰aŠ ˆ À60.3 (c ˆ 1.0, CHCl3). IR (film): 2965m, 1654m, 1589m, 1565m, 1514s, 1448m, 1384w, 1334s, 1304s,
D
1
1096m, 1039m, 973w, 900m, 8 52m, 78 5m, 734s, 709w. H-NMR: 8.09 (dd, J ˆ 8.3, 1.2, 1 arom. H); 8.14 (dd, J ˆ
8.2, 1.3, 1 arom. H); 7.61 7.56, 7.27 7.19 (2m, 2 arom. H); 5.24 (t, J ˆ 2.5, 1 H of ˆCH2); 4.86 (t, J ˆ 2.1, 1 H of
ˆCH2); 2.44 (d, J ˆ 16.1, 1 H); 2.07 1.92 (m, 2 H); 1.80 1.72 (m, 2 H); 1.41 1.33 (m, 1 H); 1.22 1.13
(m, 1 H); 0.97, 0.83 (2s, 2 Me). 13C-NMR: 153.1 (s, C(2)); 144.6, 138.6 (2s, 2 arom. C); 132.6, 127.2, 124.9, 124.8
(4d, 4 arom. CH); 105.0 (t, ˆCH2); 66.3 (s, C(1)); 49.6 (s, C(7)); 42.7 (d, C(4)); 36.0 (t, C(6)); 32.0 (t, C(3)); 26.9
‡
‡
(t, C(5)); 18.8 (q, 2 MeÀC(7)). CI-MS (NH3): 340 (16), 339 (100, [M ‡ NH4] , 322 (82, [M ‡ 1] ), 169 (12,
‡
[C10H16S ‡ 1] ). Anal. calc. for C16H19NO2S2 (321.46): C 59.78, H 5.96, N 4.36, S 19.95; found: C 59.58, H 6.23, N
4.28, S 19.91.
5. X-Ray Crystal-Structure Determination of 10 and 14 (see Table 2, and Figs. 1 and 2)4). All measurements
were made on a Nonius KappaCCD diffractometer [10] with graphite-monochromated MoKa radiation (l
0.71073 ä) and an Oxford Cryosystems Cryostream 700 cooler. Data reduction was performed with HKL Denzo
and Scalepack [11]. The intensities were corrected for Lorentz and polarization effects, and an absorption
correction based on the multi-scan method [12] was applied. Equivalent reflections, other than Friedel pairs for
10, were merged. Data collection and refinement parameters are given in Table 2, and views of the molecules are
shown in Figs. 1 and 2. The structure of 10 was solved by direct methods with SIR92 [13], which revealed the
positions of all non-H-atoms. In the case of 14, the structure was solved by heavy-atom Patterson methods [14],
which revealed the positions of the S- and Cl-atoms. All remaining non-H-atoms were located in a Fourier
expansion of the Patterson solution, which was performed with DIRDIF 94 [15]. The non-H-atoms were refined
anisotropically. All of the H-atoms were placed in geometrically calculated positions and refined by using a
riding model where each H-atom was assigned a fixed isotropic displacement parameter with a value equal to
1.2Ueq of its parent C-atom (1.5Ueq for the Me groups). Refinement of each structure was carried out on F2 by
À
Á2
full-matrix least-squares procedures, which minimized the function Sw F2o À Fc2 . A correction for secondary
3
)
)
In contrast to the analogous reaction with 6, the yield of 16a (and 16b) decreased significantly after longer
reaction time or at increased temp.
CCDC-221849-221850 contain the supplementary crystallographic data for this paper. These data can be
obtained free of charge via www.ccde.cam.ac.uk/cibts/retrieving.html (or from the Cambridge Crystal-
lographic Data Centre, 12 Union Road, Cambridge CB2IEZ, U.K.; fax: ‡441223336033; e-mail:
deposit@ccdc.cam.ac.uk).
4

798
Helvetica Chimica Acta Vol. 87 (2004)
Table 2. Crystallographic Data of 10 and 14
10
14
Crystallized from
hexane
hexane
Empirical formula
Formula weight [g molÀ1
Crystal color, habit
Crystal dimensions [mm]
Temperature [K]
Crystal system
C18H27ClOS2
358.98
colorless, prism
0.10 Â 0.12 Â 0.25
160(1)
C18H27ClOS2
358.98
colorless, plate
0.02 Â 0.07 Â 0.25
160(1)
]
monoclinic
P21
triclinic
≈
Space group
P1
Z
2
2
Reflections for cell determination
36333
31804
2q Range for cell determination [8]
4
60
4 52
Unit cell parameters a [ä]
6.3437(1)
11.1033(2)
13.2624(2)
90
91.3277(6)
90
933.90(3)
1.276
0.4280.431
f and w
60
6.7667(2)
11.1820(4)
12.3873(4)
88.370(2)
86.078(2)
82.374(2)
926.65(5)
1.286
b [ä]
c [ä]
a [8]
b [8]
g [8]
V [ä3]
Dx [g cmÀ3
]
m(MoKa) [mmÀ1
Scan type
]
w
2q(max) [8]
52
Transmission factors (min; max)
Total reflections measured
Symmetry independent reflections
Reflections with I > 2s(I)
Reflections used in refinement
Parameters refined; restraints
Final R(F) [I > 2s(I) reflections]
wR(F2) (all data)
0.869; 0.963
43942
5450
4695
5450
205; 1
0.03280.0407
0.0737
0.0360; 0.1051
1.034
0.820; 0.996
14008
3618
2932
3618
206
0.1085
0.0543; 0.4305
1.037
Weighting parameters [a; b]a)
Goodness-of-fit
Secondary extinction coefficient
Final Dmax/s
0.009(2)
0.001
0.34; À 0.33
0.001
0.22; À 0.32
D1(max; min) [e äÀ3
]
a) wÀ1 ˆ s2(F2o) ‡ (aP)2 ‡ bP where P ˆ (Fo2 ‡ 2F2c )/3.
extinction was applied for 14. In the case of 10, refinement of the absolute structure parameter [16] yielded a
value of À 0.10(4), which confidently confirms that the refined coordinates represent the true enantiomorph.
Neutral-atom scattering factors for non-H-atoms were taken from [17a], and the scattering factors for H-atoms
were taken from [18]. Anomalous dispersion effects were included in Fc [19]; the values for f ' and f '' were those
of [17b]. The values of the mass attenuation coefficients are those of [17c]. All calculations were performed
using the SHELXL97 [20] program.
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[3] A. Linden, A. Majchrzak, J. Cavegn, G. Mloston, H. Heimgartner, Acta Crystallogr., Sect. C 2002, 58, o480.

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Received October 17, 2003