Hypervalent S-Cl bond in cyclic acylaminochloro-λ4-sulfanes: A comparison of N-S-Cl, N-S+ClO4/- and N-S+···O=C bond systems

Article abstract of DOI:10.1016/S0022-2860(98)00543-2

Two cyclic acylaminochloro-λ⁴-sulfanes containing a five- or a six- membered hetero ring (5 and 6), as well as their cyclic acylaminosulfonium salt analogues without (7 and 8) and with S···O close contact (9 and 10), have been prepared and thei

Full text of DOI:10.1016/S0022-2860(98)00543-2

Journal of Molecular Structure 476 (1999) 157–171
Hypervalent S–Cl bond in cyclic acylaminochloro-l4-sulfanes: a
comparison of N–S–Cl, N–SϩClO4Ϫ and N–Sϩ OyC bond
…
systems
a,
a
a
b
b
´
*
´
´
´
´
´
Denes Szabo , Istvan Kapovits , Arpad Kucsman , Peter Nagy , Gyula Argay ,
b
´
´
Alajos Kalman
a
¨
¨
Department of Organic Chemistry, Eotvos Lorand University, PO Box 32, H-1518 Budapest 112, Hungary
bInstitute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, PO Box 17, H-1525 Budapest, Hungary
Received 3 June 1998; accepted 2 July 1998
Abstract
Two cyclic acylaminochloro-l4-sulfanes containing a five- or a six-membered hetero ring (5 and 6), as well as their cyclic
…
acylaminosulfonium salt analogues without (7 and 8) and with S O close contact (9 and 10), have been prepared and their
molecular structures determined by X-ray diffraction. Compounds 5, 6, 9 and 10 exhibit a trigonal bipyramidal configuration
about the central sulfur atom, with nitrogen and chlorine (in 5 and 6) or with nitrogen and oxygen atoms (in 9 and 10) in axial
positions. In sulfonium salts 7 and 8, the bond angles about sulfur are similar to those obtained for analogous l4-sulfanes 5 and
˚
6. The interatomic S–N distances, which range from 1.66 to 1.73 A, point to a strong covalent bond in all compounds
4
˚
˚
investigated. In l -sulfanes the axial S–Cl hypervalent bond (2.69 A in 5, 3.10 A in 6) is rather long and markedly polarized.
In methoxycarbonyl-substituted acylaminosulfonium salts the interatomic S O distances are 2.41 A (in 9) and 2.74 A (in 10).
…
˚
˚
…
The individual S–N, S–Cl, S O and S–Car bond lengths, as well as the N(ax)–S–X(ax) (X ˆ Cl or Oy), N(ax)–S–Car(eq),
Cl(ax)–S–Car(eq) and Car(eq)–S–Car 0ꢀeq† bond angles (159–176Њ, 90–104Њ, 85–96Њ and 101–104Њ, respectively), which
depend on both the axial substituents on sulfur and the size of the hetero ring, are compared and discussed. The five-membered
2,3-dihydro-isothiazole rings in 5, 7 and 9 are practically planar, whereas the 1,2-oxathiole ‘‘ring’’ in 10 is unusually puckered.
The six-membered dihydro-1,2-thiazine rings in 6, 8 and 10, as well as the 1,2-oxathiine ‘‘ring’’ in 9, assume a more or less
inverted half-chair form. The orientations of the aromatic rings in relation to the Car(eq)–S–Car 0ꢀeq† plane are also discussed.
᭧ 1999 Elsevier Science B.V. All rights reserved.
Keywords: Chloro-l4-sulfanes; Sulfonium salts; Hypervalent bonds; Sulfur–oxygen interaction
1. Introduction
suggested to be reactive intermediates involved in
the formation of bicyclic diarylbis(acyloxy)-l4-
sulfanes from diaryl sulfides and halogenating agents.
Later, some stable representatives of cyclic chloro-l4-
sulfanes (e.g., 1b and 3) were prepared by the same
method and investigated by X-ray diffraction [2–4].
When appropriate disubstituted diaryl sulfides
were submitted to S-halogenation, alkoxy- and
In an earlier paper [1] monocyclic diarylacyloxy-
chloro-l4-sulfanes (e.g., 1a) and/or the corresponding
diarylacyloxysulfonium chlorides (e.g., 2a) are
* Corresponding author. Tel.: ϩ 36-1-209-0555; Fax: ϩ 36-1-
209-0602; e-mail: szabod@szerves.chem.elte.hu.
0022-2860/99/$ - see front matter ᭧ 1999 Elsevier Science B.V. All rights reserved.
PII: S0022-2860(98)00543-2

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
158
acylaminosulfonium salts (chlorides or perchlorates)
sulfonium salts [13] assume l4-sulfane-like structure
in which the X–Sϩ moiety is stabilized by an intra-
…
stabilized by S O close contact (e.g., 2c and 2d)
1
…
…
were also isolated [5–7]. H nuclear magnetic reso-
molecular S O or S N close contact in axial direc-
tions. These contacts, where the atomic distances are
shorter than the sum of the van der Waals’ radii, may
be regarded as very weak and extremely elongated
‘‘nonclassical’’ hypervalent bonds that cannot be
represented by the classical valence symbols.
nance (NMR) studies showed that compounds exhi-
biting alkoxychloro-l4-sulfane structure in the solid
state or in apolar solvents (e.g., in CDCl3) may
undergo ionization in dipolar solvents (e.g., in
CD3OD) to yield the corresponding alkoxysulfonium
chloride (1b ! 2b and 3 ! 4) [2, 4].
In order to elucidate the different bond systems and
geometry of nonsymmetric chloro-l4-sulfanes, we
prepared two cyclic acylaminochloro-l4-sulfanes
containing a five- or a six-membered hetero ring (5
and 6), as well as their cyclic acylaminosulfonium salt
Stable l4-sulfanes with an axial X–S–Y moiety, in
which X and Y represent hetero atoms (such as
nitrogen, oxygen and chlorine), are excellent models
for studying hypervalent bond systems involving the
sulfur atom [5–12]. In symmetric l4-sulfanes (X ˆ Y)
the hypervalent S–X bond is markedly longer than the
corresponding covalent bond, but much shorter than
the sum of the van der Waals’ radii. In nonsymmetric
l4-sulfanes (X ± Y) the hypervalent bond system
becomes ‘‘unbalanced’’. The short S–X bond with a
less electronegative atom X is practically covalent,
whereas the elongated S–Y hypervalent bond with a
more electronegative atom Y is markedly polarized
towards a zwitterionic sulfonium salt structure.
Some alkoxy- [6, 11], acylamino- [6, 7] and chloro-
…
analogues without (7 and 8) and with S O close
contact (9 and 10), and determined their structure by
the X-ray diffraction method.
The results published in this paper provide an
opportunity both to compare the structural parameters
of different cyclic compounds having N–S–Cl or N–
SϩClOϪ4 or N–S OyC structural parts and to find
…
correlations between their structure and reactivity.
Kinetic measurements on the hydrolysis of
compounds 5–10 are in progress and the results will
be published elsewhere.

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
159
1.1. Model compounds
2. Experimental
To obtain chloro-l4-sulfane 5, 2-phenylthiobenzoic
acid (11) [14] was first converted into N-methyl-2-
phenylthio benzamide (12) through the corre-
sponding acid chloride (path i). Amide 12 was
treated with t-butyl hypochlorite at room tempera-
ture to give 5 (path ii). The treatment of 5 with
AgClO4 in methanol yielded sulfonium perchlorate
7 (path iii).
2.1. Materials
¨
Melting points (mp) were determined on a Boetius
micro melting point apparatus. Infrared (IR) spectra
were taken on a Specord IR 75 (Zeiss, Jena) spectro-
1
photometer. H-NMR measurements were made on a
Bruker WP 80SY instrument. Microanalyses were
carried out in the microanalytical laboratory of the
Department of Organic Chemistry by Dr H. Medzih-
radszky-Schweiger and co-workers.
Solvents were purified and dried by the usual
methods. Evaporations were carried out under reduced
pressure. Products obtained from reaction mixtures or
by crystallization were dried in vacuo over P2O5 or
KOH pellets, depending on the solvent used.
Chloro-l4-sulfane 6 and sulfonium perchlorate 8
were prepared by a similar procedure starting from
8-phenylthio-1-naphthoic acid (13) [15].
Sulfonium chlorides 9 and 10 were obtained from
methyl
8-[2-(N-methylcarbamoyl)-1-phenylthio]
naphthoate (15) and methyl 2-[8-(N-methylcarba-
moyl)-1-naphthylthio] benzoate (16), respectively,
by treating them with t-butyl hypochlorite at room
temperature. Methyl esters 15 and 16 were prepared
from the corresponding carboxylic acids [7] with
diazomethane (Scheme 1).
2.2. N-Methyl-2-(phenylthio)benzamide (12)
To sulfide carboxylic acid 11 [14] (10 g, 0.043 mol)

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
160
Scheme 1. Reagents and conditions: (i) SOCl2, reflux, 2 h, then MeNH2 in THF; (ii) ButOCl, CH2Cl2, 20ЊC; (iii) AgClO4, MeOH, 20ЊC.
was added thionyl chloride (11 cm3, 0.15 mol) and the
reaction mixture was refluxed for 2 h. After evapora-
tion of the excess thionyl chloride in vacuo, the
residue (crude acid chloride) was dissolved in dry
dioxane (30 cm3) and methylamine (3.7 g, 0.12 mol)
in tetrahydrofuran (THF) (30 cm3) was added drop-
wise to the stirred solution at room temperature. The
reaction mixture was allowed to stand overnight then
the solvent was removed in vacuo, the residue tritu-
rated with water (30 cm3), filtered and dried to give
sulfide 12 (9.8 g, 94% yield), mp 104–105ЊC (EtOH–
H2O: mp 105.5–106.5ЊC in [16]).
0.01 mol) in dry CH2Cl2 (12 cm3), ButOCl
(1.25 cm3, 0.01 mol) was added dropwise at
room temperature under stirring. After further stir-
ring (1 h) pentane (1 cm3) was added to the solu-
tion, which was allowed to stand overnight (4ЊC).
The crystals precipitated were then filtered off,
washed with pentane and dried to yield chloro-
l4-sulfane 5 (1.50 g, 54% yield), mp 165–190ЊC
(dec.) Elemental analysis — found: C, 60.3; H,
4.2; Cl, 12.6; N, 5.1; S, 11.3. C14H12ClNOS
requires: C, 60.54; H, 4.35; Cl, 12.76; N, 5.04;
S, 11.54%). IR — nmax (cmϪ1) (KBr): 1700vs
(CyO). NMR
— dH (ppm) (80 MHz, CDCl3;
2.3. 2,3-Dihydro-1-chloro-1-phenyl-2-methyl-3-oxo-
1,2-benzisothiazole (5)
SiMe4): 3.20 (s, Me), 7.2–9.8 (m, ArH); dH
(ppm) (80 MHz, CD3OD; SiMe4): 3.38 (s, Me),
7.6–8.4 (m, ArH).
To
a
suspension of sulfide 12 (2.43 g,

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
161
4
˚
Fig. 1. Stereoscopic view of chloro-l -sulfane 5 with numbering scheme for nonhydrogen atoms. Selected bond lengths (A) and angles (Њ) are
as follows: S(1)–N(1), 1.727(1); S(1)–Cl(1), 2.690(1); S(1)–C(1), 1.794(1); S(1)–C(8), 1.793(1); C(1)–C(2), 1.389(1); C(2)–C(7), 1.479(1);
N(1)–C(7), 1.367(1); C(7)–O(1), 1.218(1); N(1)–S(1)–Cl(1), 175.6(1); C(1)–S(1)–C(8), 103.8(1); N(1)–S(1)–C(1), 89.6(1); N(1)–S(1)–C(8),
98.4(1); Cl(1)–S(1)–C(1), 92.8(1); Cl(1)–S(1)–C(8), 84.6(1); S(1)–C(1)–C(2), 110.7(1); C(1)–C(2)–C(7), 114.0(1); C(2)–C(7)–N(1),
108.6(1); C(7)–N(1)–S(1), 117.1(1); C(2)–C(7)–O(1), 127.4(1); N(1)–C(7)–O(1), 124.0(1); C(7)–N(1)–C(14), 122.5(1); S(1)–N(1)–
C(14), 120.1(1); S(1)–C(1)–C(2)–C(7), Ϫ 0.7(1); C(1)–C(2)–C(7)–N(1), 1.2(1); C(2)–C(7)–N(1)–S(1), Ϫ 1.2(1); C(7)–N(1)–S(1)–
C(1), 0.7(1); N(1)–S(1)–C(1)–C(2), 0.0(1); N(1)–S(1)–C(8)–C(9), Ϫ 91.5(1); C(1)–S(1)–C(8)–C(9), 0.1(1); C(8)–S(1)–C(1)–C(2),
Ϫ 98.5(1); Cl(1)–S(1)–C(1)–C(2), 176.3(1); Cl(1)–S(1)–C(8)–C(9), 91.8(1); S(1)–N(1)–C(7)–O(1), 177.2(2); C(1)–C(2)–C(7)–O(1),
Ϫ 177.1(2); C(14)–N(1)–C(7)–O(1), 3.0(2).
2.4. 2,3-Dihydro-1-phenyl-2-methyl-3-oxo-
8.5 (m, ArH); dH (ppm) (80 MHz, CD3OD; SiMe4):
benzisothiazol-1-ium perchlorate (7)
3.37 (s, Me), 7.3–8.5 (m, ArH).
To a solution of chloro-l4-sulfane 5 (1.39 g,
0.005 mol) in dry methanol (8 cm3) was added
AgClO4 (1.04 g, 0.005 mol) in water-free methanol
(6 cm3). The reaction mixture was stirred for 2 h at
room temperature and then the precipitate (AgCl) was
filtered off. The solvent was removed in vacuo to give
sulfonium perchlorate 7 (1.03 g, 60% yield), mp 99–
112ЊC. Elemental analysis — found: C, 48.9; H, 3.3;
N, 3.9; S, 9.3. C14H12ClNO5S requires: C, 49.20; H,
3.54; N, 4.10; S, 9.38%). IR — nmax (cmϪ1) (KBr):
1710vs (CyO), 1080vs, 620s (ClO4). NMR — dH
(ppm) (80 MHz, CDCl3; SiMe4): 3.40 (s, Me), 7.2–
2.5. N-Methyl-8-phenylthio-1-naphthamide (14)
Starting from 8-phenylthio-1-naphthoic acid (13)
[15], naphthamide derivative 14 was synthesized by
the method described for the preparation 12 (94%
yield), mp 172–173ЊC. Elemental analysis
—
found: C, 73.5; H, 5.1; N, 4.7; S, 10.8. C18H15NOS
requires: C, 73.69; H, 5.15; N, 4.77; S, 10.93%. IR —
nmax (cmϪ1) (KBr): 3278s (NH), 1638s, 1622vs
(CyO). NMR
— dH (ppm) (80 MHz, CDCl3;
SiMe4): 2.90 (d, Me, J ˆ 5 Hz), 6.9–8.1 (m, ArH).

´
162
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
4
˚
Fig. 2. Stereoscopic view of chloro-l -sulfane 6 with numbering scheme for nonhydrogen atoms. Selected bond lengths (A) and angles (Њ) are
as follows: S(1)–N(1), 1.675(1); S(1)–Cl(1), 3.101(1); S(1)–C(1), 1.763(1); S(1)–C(12), 1.796(1); C(1)–C(9), 1.420(1); C(9)–C(8), 1.421(1);
C(8)–C(11), 1.481(1); N(1)–C(11), 1.396(1); C(11)–O(1), 1.215(1); N(1)–S(1)–Cl(1), 158.9(1); C(1)–S(1)–C(12), 102.5(1); N(1)–S(1)–
C(1), 100.6(1); N(1)–S(1)–C(12), 103.5(1); Cl(1)–S(1)–C(1), 95.6(1); Cl(1)–S(1)–C(12), 86.0(1); S(1)–C(1)–C(9), 117.6(1); C(1)–C(9)–
C(8), 123.6(1); C(9)–C(8)–C(11), 122.1(1); C(8)–C(11)–N(1), 117.3(1); C(11)–N(1)–S(1), 124.1(1); C(8)–C(11)–O(1), 123.1(1); N(1)–
C(11)–O(1), 119.3(1); C(11)–N(1)–C(18), 118.8(1); S(1)–N(1)–C(18), 115.9(1); S(1)–C(1)–C(9)–C(8), Ϫ 11.8(1); C(1)–C(9)–C(8)–
C(11), Ϫ 14.9(1); C(9)–C(8)–C(11)–N(1), 10.6(1); C(8)–C(11)–N(1)–S(1), 22.3(1); C(11)–N(1)–S(1)–C(1), Ϫ 41.4(1); N(1)–S(1)–
C(1)–C(9), 34.5(1); N(1)–S(1)–C(12)–C(13), 62.7(1); C(1)–S(1)–C(12)–C(13), 167.1(2); C(12)–S(1)–C(1)–C(9), Ϫ 72.0(1); Cl(1)–
S(1)–C(1)–C(9), Ϫ 159.2(2); Cl(1)–S(1)–C(12)–C(13), Ϫ 98.1(2); S(1)–N(1)–C(11)–O(1), Ϫ 164.5(2); C(9)–C(8)–C(11)–O(1),
Ϫ 162.3(2); C(18)–N(1)–C(11)–O(1), 2.8(1).
2.6. 2,3-Dihydro-1-chloro-1-phenyl-2-methyl-3-oxo-
naphtho-(1,8-d,e)-1,2-thiazine (6)
(80 MHz, CD3OD; SiMe4): 3.71 (s, Me), 7.5–8.9 (m,
ArH).
Starting from sulfide 14, chloro-l4-sulfane 6 was
prepared by the procedure given above for the synth-
esis of 5 (83% yield), mp 216–218ЊC. Elemental
analysis — found: C, 65.7; H, 4.2; Cl, 10.7; N, 4.2;
S, 9.8. C18H14ClNOS requires: C, 65.95; H, 4.30; Cl,
10.82; N, 4.27; S, 9.78%. IR — nmax (cmϪ1) (KBr):
1680vs (CyO). NMR — dH (ppm) (80 MHz, CDCl3;
SiMe4): 3.85 (s, Me), 7.3–10.1 (m, ArH); dH (ppm)
2.7. 2,3-Dihydro-1-phenyl-2-methyl-3-oxo-naphtho-
(1,8-d,e)-1,2-thiazin-1-ium perchlorate (8)
Compound 8 was prepared from chloro-l4-sulfane
6 by the procedure given for the synthesis of sulfo-
nium salt 7 (47% yield), mp 169–171ЊC. Elemental
analysis — found: C, 54.8, H, 3.7, N, 3.4; S, 8.0.
C18H14ClNO5S requires: C, 55.18; H, 3.60; N, 3.57;

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
163
Fig. 3. Stereoscopic view of sulfonium salt 7 with numbering scheme for nonhydrogen atoms; the ClOϪ4 anion is also shown. Selected bond
˚
…
lengths (A) and angles (Њ) are as follows: S(1)–N(1), 1.678(2); S(1) O(2), 3.068(2); S(1)–C(1), 1.764(3); S(1)–C(8), 1.779(3); C(1)–C(2),
…
1.385(4); C(2)–C(7), 1.472(4); N(1)–C(7), 1.404(4); C(7)–O(1), 1.215(3); N(1)–S(1) O(2), 78.4(1); C(1)–S(1)–C(8), 102.3(2); N(1)–S(1)–
…
…
C(1), 91.6(2); N(1)–S(1)–C(8), 103.4(2); C(1)–S(1) O(2), 71.6(2); C(8)–S(1) O(2), 173.7(2); S(1)–C(1)–C(2), 111.2(3); C(1)–C(2)–C(7),
112.6(4); C(2)–C(7)–N(1), 109.4(4); C(7)–N(1)–S(1), 115.0(3); C(2)–C(7)–O(1), 128.4(5); N(1)–C(7)–O(1), 122.3(5); C(7)–N(1)–C(14),
124.6(4); S(1)–N(1)–C(14), 120.2(3); S(1)–C(1)–C(2)–C(7), Ϫ 3.0(3); C(1)–C(2)–C(7)–N(1), Ϫ 0.2(4); C(2)–C(7)–N(1)–S(1), 3.6(3);
C(7)–N(1)–S(1)–C(1), Ϫ 4.5(3); N(1)–S(1)–C(1)–C(2), 4.2(3); N(1)–S(1)–C(8)–C(13), 37.0(4); C(1)–S(1)–C(8)–C(13), Ϫ 57.7(4); C(8)–
S(1)–C(1)–C(2), 108.3(3); S(1)–N(1)–C(7)–O(1), Ϫ 177.7(6); C(1)–C(2)–C(7)–O(1), Ϫ 178.9(5); C(14)–N(1)–C(7)–O(1), Ϫ 1.7(5).
S, 8.18%. IR — nmax (cmϪ1) (KBr): 1700s (CyO),
1085vs, 620s (ClO4). NMR — dH (ppm) (80 MHz,
CDCl3; SiMe4): 3.73 (s, Me), 7.4–9.1 (m, ArH); dH
(ppm) (80 MHz, CD3OD; SiMe4): 3.68 (s, Me), 7.2–
8.9 (m, ArH).
respectively). Data for 15: mp 162–165ЊC. Elemental
analysis — found: C, 68.1; H, 4.8; N, 4.0; S, 8.9.
C20H17NO3S requires: C, 68.36; H, 4.88; N, 3.99; S,
9.12%). IR — nmax (cmϪ1) (KBr): 3270m (NH),
1718vs, 1622s (CyO). NMR — dH (ppm) (80 MHz,
CDCl3; SiMe4): 2.69 (d, Me–N, J ˆ 5.2 Hz), 3.93 (s,
Me–O), 6.7–8.1 (m, ArH). Data for 16: mp 182–
183ЊC. Elemental analysis — found: C, 68.2; H,
4.9; N, 3.8; S, 9.0. C20H17NO3S requires: C, 68.36;
2.8. Methyl 8-[2-(N-methylcarbamoyl)-1-phenylthio]
naphthoate (15) and methyl 2-[8-(N-
methylcarbamoyl)-1-naphthylthio] benzoate (16)
H, 4.88; N, 3.99; S, 9.12%. IR — nmax (cmϪ1
)
(KBr): 3275m (NH), 1698vs, 1630vs (CyO). NMR
— dH (ppm) (80 MHz, CDCl3; SiMe4): 2.83 (d,
Me–N, J ˆ 5.4 Hz), 3.91 (s, Me–O), 6.3–8.1 (m,
ArH).
Compounds 15 and 16 were prepared from
the corresponding carboxylic acids [7] with
diazomethane in methanol (85 and 88% yield,

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
164
Fig. 4. Stereoscopic view of sulfonium salt 8 with numbering scheme for nonhydrogen atoms; the ClOϪ4 anion is also shown. Selected bond
˚
…
lengths (A) and angles (Њ) are as follows: S(1)–N(1), 1.651(2); S(1) O(5A), 3.29(2); S(1)–C(1), 1.759(1); S(1)–C(12), 1.797(2); C(1)–C(9),
…
1.413(3); C(9)–C(8), 1.411(3); C(8)–C(11), 1.474(3); N(1)–C(11), 1.406(3); C(11)–O(1), 1.207(2); N(1)–S(1) O(5A), 130.5(3); C(1)–S(1)–
…
…
C(12), 102.1(2); N(1)–S(1)–C(1), 102.3(2); N(1)–S(1)–C(12), 105.5(2); C(1)–S(1) O(5A), 116.2(3); C(8)–S(1) O(5A), 169.3(3); S(1)–
C(1)–C(9), 118.2(2); C(1)–C(9)–C(8), 123.1(3); C(9)–C(8)–C(11), 122.5(3); C(8)–C(11)–N(1), 118.1(3); C(11)–N(1)–S(1), 124.6(3); C(8)–
C(11)–O(1), 123.4(3); N(1)–C(11)–O(1), 119.3(3); C(11)–N(1)–C(18), 119.3(3); S(1)–N(1)–C(18), 115.2(3); S(1)–C(1)–C(9)–C(8),
Ϫ 13.2(2); C(l)–C(9)–C(8)–C(11), Ϫ 13.6(3); C(9)–C(8)–C(11)–N(1), 14.7(3); C(8)–C(11)–N(1)–S(1), 13.1(2); C(11)–N(1)–S(1)–C(1),
Ϫ 33.1(3); N(1)–S(1)–C(1)–C(9), 32.4(3); N(1)–S(1)–C(12)–C(13), 3.2(3); C(1)–S(1)–C(12)–C(13), 109.9(3); C(12)–S(1)–C(1)–C(9),
Ϫ 76.8(2); C(12)–S(1)–C(1)–C(9), Ϫ 76.8(2); S(1)–N(1)–C(11)–O(1), Ϫ 171.5(4); C(9)–C(8)–C(11)–O(1), Ϫ 160.6(4); C(18)–N(1)–
C(11)–O(1), Ϫ 3.1(4).
2.9. 2,3-Dihydro-1-[8-(methoxycarbonyl)-1-
naphthyl]-2-methyl-3-oxo-1,2-benzisothiazol-1-ium
chloride (9) and 2,3-dihydro-1-[2-
(methoxycarbonyl)phenyl]-2-methyl-3-oxo-naphtho-
(1,8-d,e)-1,2-thiazin-1-ium chloride (10)
62.25; H, 4.18; Cl, 9.19; N, 3.63; S, 8.31%. IR —
nmax (cmϪ1) (KBr): 1702vs, 1670vs (CyO). NMR —
dH (ppm) (80 MHz, CDCl3; SiMe4): 3.84 (s, Me–N),
4.18 (s, Me–O), 7.2–9.5 (m, ArH).
2.10. Crystal structure determinations
Compounds 9 and 10 were synthesized from the
sulfides 15 and 16, respectively, with ButOCl by the
procedure described for the preparation of compound
5 (56 and 34% yield, respectively). Data for 9: mp
241–248ЊC. Elemental analysis — found: C, 62.0;
H, 4.1; Cl, 9.0; N, 3.7; S, 8.0. C20H16ClNO3S requires:
C, 62.25; H, 4.18; Cl, 9.19; N, 3.63; S, 8.31%. IR —
nmax (cmϪ1) (KBr): 1727vs, 1670vs (CyO). NMR —
dH (ppm) (80 MHz, CDCl3; SiMe4): 3.51 (s, Me–N),
4.27 (s, Me–O). Data for 10: mp 268–271ЊC.
Elemental analysis — found: C, 62.0; H, 4.2; Cl,
9.2; N, 3.8; S, 8.2. C20H16ClNO3S requires: C,
The molecular structure for acylaminochloro-l4-
sulfanes 5 and 6, acylaminosulfonium perchlorates 7
and 8, and methoxycarbonyl-substituted derivatives 9
and 10 were determined by single-crystal X-ray
diffraction methods. The perspective views are
shown in Figs. 1–6. Selected bond lengths, bond
angles and torsion angles are listed in the figure
captions.
X-ray-quality single crystals were grown from a
solvent mixture of CH2Cl2–cyclohexane for 5,
CH2Cl2–pentane for 6, CH2Cl2–benzene for 7 and

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
165
Fig. 5. Stereoscopic view of methoxycarbonyl-substituted sulfonium salt 9 with numbering scheme for nonhydrogen atoms; the ClϪ anion is
˚
…
also shown. Selected bond lengths (A) and angles (Њ) are as follows: S(1)–N(1), 1.685(1); S(1) O(2), 2.408(1); S(1)–C(1), 1.789(1); S(1)–
C(8), 1.811(1); C(1)–C(2), 1.388(2); C(2)–C(7), 1.471(2); N(1)–C(7), 1.389(2); C(7)–O(1), 1.211(2); C(15)–C(19), 1.478(2); C(19)–O(2),
…
…
1.214(2); C(19)–O(3), 1.322(2); S(1) Cl(1), 3.463(1); N(1)–S(1) O(2), 169.9(1); C(8)–S(1)–C(1), 103.0(1); N(1)–S(1)–C(1), 90.61(1);
…
…
N(1)–S(1)–C(8), 103.0(1); O(2) S(1)–C(1), 87.8(1); O(2) S(1)–C(8), 87.0(1); S(1)–C(1)–C(2), 110.2(2); C(1)–C(2)–C(7), 113.8(2);
C(2)–C(7)–N(1), 108.5(2); C(7)–N(1)–S(1), 116.6(2); C(2)–C(7)–O(1), 128.2(2); N(1)–C(7)–O(1), 123.3(2); C(7)–N(1)–C(18), 122.9(2);
S(1)–N(1)–C(18), 119.9(2); O(2) S(1)–C(8), 87.0(1); S(1)–C(8)–C(16), 121.9(2); C(8)–C(16)–C(15), 128.2(2); C(16)–C(15)–C(19),
121.7(2); C(15)–C(19)–O(2), 123.2(2); C(19)–O(2) S(1), 109.8(2); C(15)–C(19)–O(3), 114.0(2); O(2)–C(19)–O(3), 122.7(2); N(1)–
S(1) Cl(1), 99.8(1); S(1)–C(1)–C(2)–C(7), 3.2(1); C(1)–C(2)–C(7)–N(1), 0.9(2); C(2)–C(7)–N(1)–S(1), Ϫ 5.0(1); C(7)–N(1)–S(1)–
…
…
…
C(1), 6.0(1); N(1)–S(1)–C(1)–C(2), Ϫ 5.0(2); N(1)–S(1)–C(8)–C(9), Ϫ 31.1(2); C(1)–S(1)–C(8)–C(16), Ϫ 122.8(1); C(8)–S(1)–C(1)–
C(2), Ϫ 108.6(2); S(1)–C(8)–C(16)–C(15), 12.5(2); C(8)–C(16)–C(15)–C(19), 15.3(2); C(16)–C(15)–C(19)–O(2), 13.3(2); C(15)–C(19)–
…
…
…
…
O(2) S(1), Ϫ 48.0(8); C(19)–O(2) S(1)–C(8), 56.0(2); O(2) S(1)–C(8)–C(16), Ϫ 35.8(2); O(2) S(1)–C(8)–C(9), 165.0(2); C(16)–
C(15)–C(19)–O(3), Ϫ 171.0(2); C(15)–C(19)–O(3)–C(20), 178.8(3); O(2)–C(19)–O(3)–C(20), Ϫ 5.5(2).
MeOH–Et2O for 8, 9 and 10. Table 1 summarizes the
relevant data concerning the crystal structure
analyses. Each data set was collected on a CAD-4
diffractometer equipped with graphite monochro-
mator. Lattice parameters were refined by a least-
squares fit for 25 reflections. Standard reflections
(three for each data collection) indicated no decay
of the crystals. All reflections were corrected for
Lorenz and polarization effects. Since data for 8
were collected with Cu Ka radiation, reflection inten-
sities were corrected against absorption by the use of
psi-scan [17].
The crystallographic phase problems were solved
by the direct method using the program shelxs86

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
166
Fig. 6. Stereoscopic view of methoxycarbonyl-substituted sulfonium salt 10 with numbering scheme for nonhydrogen atoms; the ClϪ anion is
˚
…
also shown. Selected bond lengths (A) and angles (Њ) are as follows: S(1)–N(1), 1.662(2); S(1) O(2), 2.736(2); S(1)–C(1), 1.769(2); S(1)–
C(12), 1.829(2); C(1)–C(9), 1.410(3); C(9)–C(8), 1.416(3); C(8)–C(11), 1.476(3); N(1)–C(11), 1.397(3); C(11)–O(1), 1.208(3); C(13)–C(19),
…
…
1.482(4); C(19)–O(2), 1.199(3); C(19)–O(3), 1.330(3); S(1) Cl(1), 3.258(1); N(1)–S(1) O(2), 175.0(1); C(1)–S(1)–C(12), 100.5(2); N(1)–
…
…
S(1)–C(1), 100.1(2); N(1)–S(1)–C(12), 100.8(2); O(2) S(1)–C(1), 83.7(1); O(2) S(1)–C(12), 75.2(1); S(1)–C(1)–C(9), 117.9(2); C(1)–
C(9)–C(8), 122.9(3); C(9)–C(8)–C(11), 121.9(3); C(8)–C(11)–N(1), 117.9(3); C(11)–N(1)–S(1), 124.0(2); C(8)–C(11)–O(1), 123.2(3);
N(1)–C(11)–O(1), 118.6(3); C(11)–N(1)–C(18), 118.5(3); S(1)–N(1)–C(18), 116.3(3); O(2)–S(1)–C(12), 75.2(1); S(1)–C(12)–C(13),
120.4(3); C(12)–C(13)–C(19), 119.8(3); C(13)–C(19)–O(2), 123.9(4); C(19)–O(2)–S(1), 95.1(3); O(2)–S(1)–C(1), 83.7(1); C(13)–C(19)–
…
…
…
O(3), 112.1(4); O(2)–C(19)–O(3), 124.0(4); N(1)–S(1) Cl(1), 84.0(1); C(1)–S(1) Cl(1), 89.3(1); C(12)–S(1) Cl(1), 168.1(1); S(1)–
C(1)–C(9)–C(8), Ϫ 14.7(2); C(1)–C(9)–C(8)–C(11), Ϫ 14.5(3); C(9)–C(8)–C(11)–N(1), 13.6(3); C(8)–C(11)–N(1)–S(1), 19.0(2);
C(11)–N(1)–S(1)–C(1), Ϫ 40.2(3); N(1)–S(1)–C(1)–C(9), 36.9(3); N(1)–S(1)–C(12)–C(13), Ϫ 169.7(3); C(1)–S(1)–C(12)–C(13),
Ϫ 67.2(3); C(12)–S(1)–C(1)–C(9), Ϫ 66.2(2); S(1)–C(12)–C(13)–C(19), Ϫ 7.5(3); C(12)–C(13)–C(19)–O(2), Ϫ 17.9(4); C(13)–C(19)–
…
…
…
…
O(2) S(1), 22.9(2); C(19)–O(2) S(1)–C(12), Ϫ 20.1(3); O(2) S(1)–C(12)–C(13), 13.3(2); O(2) S(1)–C(12)–C(13), Ϫ 139.9(4);
C(12)–C(13)–C(19)–O(3), 163.0(4); C(13)–C(19)–O(3)–C(20), 179.6(4); O(2)–C(19)–O(3)–C(20), 0.5(4).
[18]. The atomic positions for each structure were
refined with anisotropic displacement parameters in
F2 mode using the program shelxl93 [19]. The
hydrogen positions were generated from assumed
geometries and were refined isotropically in riding
mode. In 7, 9 and 10 there are solvent molecules
cocrystallized with the sulfonium salts. In 9 a full
molecule of methanol is embedded in the asymmetric
unit, whereas in 7 and 10 there is a half of benzene and
CH2Cl2 molecule, respectively. Both solvent mole-
cules (benzene and CH2Cl2) exhibit positional
disorder around an inversion centre of the corre-
sponding unit cell, and they are refined with 0.5–0.5
occupying factors. Similarly, in 8 the tetrahedral
ClOϪ4 anion is disordered.
Fractional atomic coordinates, bond lengths and
angles as well as thermal parameters have been depos-
ited at the Cambridge Crystallographic Data Centre.

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
167
s
s
s
s
s
s

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
168
4
˚
Scheme 2. Interatomic S–Cl distances (A): (A) S–Cl covalent bond; (B) S–Cl hypervalent bond in symmetric l -sulfanes; (C) S–Cl
hypervalent bond in nonsymmetric l4-sulfanes; (D) van der Waals’ distance.
3. Results and discussion
bond is, however, considerably longer than the same
…
bond in sulfonium salts 9 and 7, with or without S
O
˚
3.1. Sulfur configuration
close contact (1.69 and 1.68 A, respectively). (2) The
S–N bond is shorter in six-membered rings (1.68,
˚
As is expected, compounds 5 and 6 (X ˆ Cl) as well
as 9 and 10 (X ˆ O) exhibit a trigonal bipyramidal
configuration about sulfur with a nearly linear N(ax)–
S–X(ax) array (176Њ, 159Њ, 170Њ and 175Њ, respec-
tively). The remarkable deviation from linearity in
the naphthalene derivative 6 may be due to the extre-
mely long and polarized S–Cl bond (see later).
The Car=Car 0(eq)–S–X(ax) angles in compounds 5
and 6 (X ˆ Cl), and in 9 and 10 (X ˆ O) are almost
rectangular (93/85Њ, 96/86Њ, 87/88Њ and 84/75Њ,
respectively). A nearly rectangular Car(eq)–S–N(ax)
endocyclic bond angle was found only in the five-
membered ring of 5, whereas the others are markedly
wider (90/98Њ, 101/104Њ, 102/106Њ and 100/101Њ,
respectively). As in the case of other diaryl-l4-
sulfanes, the Car(eq)–S–Car 0ꢀeq† bond angles lie in a
narrow range (101–104Њ).
1.71, 1.66 and 1.65 A for compounds 6 and 5 in [7],
10 and 8) than that in five-membered ones. The bond
shortening may be ascribed to the different geometry
of the fused hetero rings. In the former case the C–N–
S part is joined to the ‘‘parallel’’ peri positions of a
naphthalene ring, whereas to the ‘‘divergent’’ ortho
positions of a benzene ring in the latter case.
3.3. S–Cl bonds
The N–S–Cl axial part of acylaminochloro-l4-
sulfanes 5 and 6 is nonsymmetric, so a ‘‘dispropor-
tion’’ of bond strengths about sulfur can be expected:
a strong and short covalent S–N bond should be asso-
ciated with a long and markedly polarized S–Cl
hypervalent bond. S–Cl bond length data for 5 and
˚
6 (2.69 and 3.10 A, respectively) give support for this
In sulfonium perchlorates 7 and 8, the ‘‘axial’’ N–
S–O(perchlorate) sequence is far from being linear
(see Figs. 3 and 4). Nevertheless, the Car–S–N (92Њ
view. Scheme 2 shows that the hypervalent S–Cl
bonds in nonsymmetric acylaminochloro-l4-sulfanes
are considerably longer than both the covalent S–Cl
0
and 102Њ), Car 0 –S–N (103 and 106Њ) and Car–S–Car
˚
˚
bond (2.04 and 2.07 A in [20, 21], and 2.19 A in the
…
bond angles (102Њ and 102Њ) for 7 and 8, respectively,
practically agree with those measured in analogous
l4-sulfane-type compounds, indicating the similarity
of configurations about sulfur.
N
S–Cl part of an S-chlorothiazocinium derivative
[13]) and the hypervalent S–Cl bond in the axial Cl–
4
˚
S–Cl part of symmetric l -sulfanes (2.26–2.32 A
[12]). It is remarkable, however, that the hypervalent
S–Cl bond lengths in acylaminochloro-l4-sulfane 5
and alkoxychloro-l4-sulfanes 1b and 3, with different
‘‘counter atoms’’ in the N/O–S–Cl axial part, do not
3.2. S–N bonds
˚
˚
The S–N interatomic distances (1.66–1.73 A) in
differ markedly (2.69, 2.75 and 2.75 A, respectively).
compounds 5–10 correspond to a strong S–N cova-
lent bond. The individual bond lengths are controlled
by both the other substituents on sulfur and the size of
the hetero ring into which the S–N bond is built. (1)
The endocyclic S–N bond in the axial Cl–S–N array
of acylaminochloro-l4-sulfanes is about as long as in
the O–S–N part of acylaminoacyloxy analogues
The hypervalent S–Cl bonds are in all cases remark-
ably shorter than the sum of the van der Waals’ radii
(3.65 A, see [22]).
Bond lengths suggest that the axial S–Cl bond in
acylaminochloro-l4-sulfanes is strongly polarized;
i.e., the electronic structure is shifted towards the zwit-
terionic state which can be represented by the pre-
dominance of the right-side contributor in the
˚
˚
(1.73 A for both 5 and compound 4 in [7]). This

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
169
…
Fig. 7. Stereoscopic view of the packing of methoxycarbonyl-substituted sulfonium salt 10 showing intermolecular S O(aminocarbonyl)
contacts: S(1) O(1) , 3.191(2) A; O(1) S(1)–C(1), 163.0(1)Њ.
a
a
…
˚
…
ϪN Sϩ–Cl $ N–Sϩ ClϪ resonance. By replacing the
five-membered ring in 5 with a six-membered one in 6
significant changes occur: a slight decrease of the S–
furthest downfield peaks are at d ˆ 8.5 and 9.1 ppm in
1
7 and 8, respectively). In contrast, when the H-NMR
spectra are taken in CD3OD solution, an ionic disso-
ciation of chloro-l4-sulfanes occurs and the difference
between chloro-l4-sulfanes and sulfonium salts disap-
pears (cf. [2, 4]). A comparison of the chemical shifts
for methyl protons gives the same result: the absorp-
tion of the corresponding structures (5 and 7; 6 and 8)
shows significant difference only in CDCl3, whereas
the spectra recorded in CD3OD are very similar.
Because acylaminochloro-l4-sulfanes undergo ionic
dissociation in polar solvents, they can be easily
converted into acylaminosulfonium perchlorates in
methanol with AgClO4 (5 ! 7 and 6 ! 8).
˚
N bond length (1.73 ! 1.68 A) is accompanied by a
remarkable increase of the hypervalent S–Cl bond
˚
distance (2.69 ! 3.10 A) and bond polarization.
These changes may cause the mentioned deviation
of the N–S–Cl moiety from perfect linearity.
The strongly dipolar structure of acylaminochloro-
l4-sulfane explains the similar geometry of chloro-l4-
sulfanes and corresponding sulfonium salts. Never-
theless, there exists a hypervalent bond between the
chlorine and sulfur atoms in chloro-l4-sulfanes, as
also supported by 1H-NMR measurements carried
out in apolar CDCl3 solution. The one proton of the
fused phenyl ring, which is in ortho position to the
sulfur atom, is forced into the region near the S–Cl
bond, causing an extremely large downfield shift (d ˆ
9.68 and 9.98 ppm for 5 and 6, respectively) related to
those of the analogous sulfonium salts 7 and 8 (the
…
3.4. S O close contacts
Methoxycarbonyl-substituted acylaminosulfonium
salts 9 and 10 represent a special type of (acylami-
no)(acyloxy)spiro-l4-sulfanes in which one of the

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
170
Table 2
From the comparison of acylaminosulfonium salts
Puckering parameters [24] for the six-membered hetero rings in
compounds 6, 8 and 10, with e.s.d. values in parentheses
…
with N–S O interaction we may also conclude that
…
the elongation of S O contact (i.e., the decrease of
the l4-sulfane character) is always accompanied by a
slight shortening of the covalent S–N bond (i.e., by an
increase of the sulfonium character).
˚
Compound
Q (A)
Q (Њ)
f (Њ)
Canonical forms
6
8
10
0.430(1)
0.381(2)
0.442(2)
66.5(1)
69.3(4)
67.4(3)
54.9(1)
63.0(4)
59.7(3)
E2 (B2,5
E2 (B2,5
E2 (B2,5
)
)
)
3.5. Other nonbonded interactions
…
S O
The unexpectedly long intramolecular
…
spiro rings is closed only by an S O close contact
involving a rather long distance between sulfur and
distance in compound 10 may be partly due to an
intermolecular S O interaction involving the central
sulfur atom and the carbonyl oxygen belonging to the
endocyclic amide part of a neighbouring molecule
(Fig. 7). The intermolecular interaction between
sulfur and the carbonyl oxygen Oa at (1/2 Ϫ x,1/2 ϩ
y,1/2 Ϫ z) (with an S O distance of 3.19 A and with
an O S–C angle of 163.0Њ) is weaker than the intra-
molecular one (2.74 A), but it may reduce the effec-
…
˚
oxygen atoms (cf. the values of 2.26–2.80 A in [7,
11]). Owing to the actual conformation (for details
see later) of the six-membered 1,2-oxathiine ‘‘ring’’
in compound 9, which is in part not far from the
…
idealized planar structure, the S O(methoxycar-
…
˚
˚
bonyl) nonbonded distance is rather short (2.41 A).
…
The methoxycarbonyl-substituted cyclic acylamino-
sulfonium salt 9 may be well compared to an analo-
gous carbamoyl-substituted cyclic alkoxysulfonium
salt (compound 6 in [11]) in which the 1,2-oxathiine
˚
tiveness of the latter.
The sulfonium compounds 7–10 are regarded as
fully ionized molecules with independent sulfonium
cations and ClOϪ4 or ClϪ anions. It may be mentioned,
however, that the S O(perchlorate) nonbonded
distance in 7 (3.07 A) and the S Cl distances in 9
…
‘‘ring’’ is closed by a more effective S O(aminocar-
˚
bonyl) close contact (2.35 A).
…
…
In contrast with compound 9, the S O(methoxy-
carbonyl) distance (2.74 A) is rather long in the
unusually puckered five-membered 1,2-oxathiole
‘‘ring’’ of acylaminosulfonium salt 10, which is
isomeric with compound 9. The elongation of the
˚
…
˚
˚
and 10 (3.46 and 3.26 A) are slightly shorter than the
sum of the van der Waals’ radii (3.25 and 3.65 A [22],
˚
respectively).
…
S
O distance is surprising because both the analo-
3.6. Conformation of hetero rings
gous carbamoyl-substituted alkoxysulfonium salt
(compound 4 in [11]) and the acylaminosulfonium
salt (compound 2 in [7]) exhibit markedly shorter
The shape of the five- and six-membered hereto
rings in compounds 5–10 was compared with that of
cyclopentene and cyclohexene discussed in detail in
[23]. As shown by torsion angles listed in the figure
captions, the five-membered 2,3-dihydro-isothiazole
rings in compounds 5, 7 and 9 are practically planar
with endocyclic torsion angles of fmax ˆ 1Њ, 4Њ, and 6Њ,
respectively. The six-membered 2,3-dihydro-1,2-thia-
zine rings in compounds 6, 8 and 10 assume a more
…
S
˚
O nonbonded distances (2.26 and 2.45 A, respec-
tively). This phenomenon may be ascribed to the
different electronic structure (conjugation) of the
methoxycarbonyl and methylaminocarbonyl substitu-
ents. In the former case the negatively less polarized
ester carbonyl oxygen, turning out from the remark-
ably distorted S–C(ar)–C(ar)–C(sp2) plane, forms a
…
weaker S O close contact than the negatively more
or less inverted half-chair (1,3-diplanar) form (fmin
Ϫ 12Њ, Ϫ 15Њ and 11Њ, fmax ˆ Ϫ 41Њ for 6; fmin
Ϫ 13Њ, Ϫ 14Њ and 15Њ, fmax ˆ Ϫ 33Њ for 8; fmin
Ϫ 15Њ, Ϫ 15Њ and 14Њ, fmax ˆ Ϫ 40Њ for 10).
ˆ
ˆ
ˆ
polarized amide carbonyl oxygen, which belongs to a
nearly planar five-membered ‘‘ring’’ in the latter case.
This view is supported by the usual CyO distance
(1.21 A) measured for the methoxycarbonyl group in
compound 10 and by the elongated CyO distances
(1.24 and 1.23 A) observed in the methylaminocar-
bonyl group of the analogous compounds mentioned
above.
˚
If we start from the puckering parameters listed in
Table 2, the six-membered hetero ring of 6, 8 and 10
may be classified as an E2 envelope which is slightly
distorted towards a B2,5 boat [24].
˚
In spirocyclic derivatives 9 and 10 the second

´
D. Szabo et al. / Journal of Molecular Structure 476 (1999) 157–171
171
…
hetero ‘‘ring’’ is closed by S O(methoxycarbonyl)
References
close contact. The conformation of the 1,2-oxathiine
‘‘ring’’ in 9 may be classified as an inverted half-chair
´
´
[1] I. Kapovits, J. Rabai, F. Ruff, A. Kucsman, Tetrahedron 35
(1979) 1869.
(1,3-diplanar) form (fmin ˆ 13Њ, 15Њ and 13Њ, fmax
ˆ
[2] J.C. Martin, T.M. Balthazor, J. Am. Chem. Soc. 99 (1977)
152.
[3] P.D. Livant, J. Org. Chem. 51 (1986) 5384.
[4] K. Onogi, M. Kido, M. Hori, T. Kataoka, H. Shimizu, Tetra-
hedron Lett. (1983) 4337.
56Њ). The five-membered 1,2-oxathiole ‘‘ring’’ in 10
is unusually puckered (fmin ˆ Ϫ 7Њ, fmax ˆ 23Њ).
3.7. Orientation of aromatic rings
´
´
¨
[5] D. Szabo, I. Kapovits, A. Kucsman, V. Fu¨lop, M. Czugler, A.
The overall conformation of cyclic l4-sulfanes and
sulfonium salts with two aryl rings (A and B) can be
characterized by the dihedral angles Car(A)–Car(A)–
S–Car(B) and Car(A)–S–Car(B)–Car(B), which
involve three atoms of the central Car(A)–S–Car(B)
plane and a further ring atom of the planar aryl
group A or B (for 5–10 see figure captions). In
spiro-l4-sulfanes both of the aromatic rings (A and
B) fused with a hetero ring are more or less perpendi-
cular to the equatorial Car(A)–S–Car(B) plane; i.e.,
these compounds assume a butterfly-like (axial–
axial) conformation (cf. [7, 10, 11]). As shown by
torsion angles, the aromatic ring A fused with a hetero
ring is nearly perpendicular to the Car(A)–S–Car(B)
plane in all of the compounds 5–10. The deviations
from the ideal 90Њ are 8Њ, 18Њ, 18Њ, 13Њ, 19Њ and 24Њ,
respectively.
Like diaryl sulfoxides exhibiting butterfly (axial–
axial) conformation [25], the ‘‘free’’ (unsubstituted or
methoxycarbonyl-substituted) aromatic ring B in
sulfonium salts 7–10 is not too far from being perpen-
dicular to the Car(A)–S–Car(B) plane. The deviations
from 90Њ are 32Њ, 29Њ, 33Њ and 23Њ, respectively. Thus
compounds 7–10 assume a distorted butterfly-like
conformation.
´
´
Kalman, Struct. Chem. 1 (1990) 305.
´
´
¨
[6] D. Szabo, I. Kapovits, A. Kucsman, M. Czugler, V. Fu¨lop, A.
´
´
Kalman, Struct. Chem. 2 (1991) 529.
´
´
[7] D. Szabo, I. Kapovits, A. Kucsman, P. Huszthy, Gy. Argay,
´
´
´
¨
M. Czugler, V. Fu¨lop, A. Kalman, T. Koritsanszky, L.
´
´
Parkanyi, J. Mol. Struct. 300 (1993) 23.
´
[8] A. Kucsman, I. Kapovits, in: F. Bernardi, I.G. Csizmadia, A.
Mangini (Eds.), Organic Sulfur Chemistry: Theoretical and
Experimental Advances, Elsevier, Amsterdam, 1985, p. 191.
[9] R.A. Hayes, J.C. Martin, in: F. Bernardi, I.G. Csizmadia, A.
Mangini (Eds.), Organic Sulfur Chemistry: Theoretical and
Experimental Advances, Elsevier, Amsterdam, 1985, p. 425.
´
´
´
´
[10] I. Kapovits, J. Rabai, D. Szabo, K. Czako, A. Kucsman, Gy.
´
´
´
´ ´
¨
Argay, V. Fu¨lop, A. Kalman, T. Koritsanszky, L. Parkanyi, J.
Chem. Soc., Perkin Trans. 2 (1993) 847.
[11] D. Szabo, I. Kapovits, Gy. Argay, M. Czugler, A. Kalman, T.
Koritsanszky, J. Chem. Soc., Perkin Trans. 2 (1997) 1045.
[12] N.C. Baenzinger, R.E. Buckles, R.J. Maner, D.T. Simpson, J.
Am. Chem. Soc. 91 (1969) 5749.
[13] F. Iwasaki, K.-Y. Akiba, Acta Crystallogr. B41 (1985) 445.
[14] J.O. Jılek, V. Seidlova, E. Svatek, M. Protiva, J. Pomykacek,
´
´
´
´
´
´
´
´
Z. Sedivy, Monatsh. Chem. 96 (1965) 182.
[15] M. Rajsner, E. Svatek, J. Metysova, M. Protiva, Collect.
´
Czech. Chem. Commun. 40 (1975) 1604.
[16] US Patent 4 018 830, 1977 (assigned to Merck); Chem. Abstr.
EN 87 22742.
[17] A.C. North, D.C. Philips, F. Mathews, Acta Crystallogr. A24
(1968) 350.
[18] G.M. Sheldrick, Acta Crystallogr. Sect. B 46 (1990) 467.
[19] G.M. Sheldrick, shelxl93, Program for Crystal Structure
Refinement, University of Gottingen, Germany, 1994.
[20] A. Kucsman, I. Kapovits, M. Czugler, L. Parkanyi, A.
In contrast, the ‘‘free’’ benzene ring B in chloro-l4-
sulfanes 5 and 6 lies practically in the Car(A)–S–
Car(B) plane as shown by Car(A)–S–Car(B)–Car(B)
torsion angles (0Њ and 15Њ, respectively). The shape
of compounds 5 and 6 may be classified as skew
(axial–equatorial) like that of diaryl sulfides [26].
¨
´
´
´
´
´
Kalman, J. Mol. Struct. 198 (1989) 339.
[21] F.H. Allen, O. Kennard, D.G. Watson, L. Brammer, A.G.
Orpen, R. Taylor, J. Chem. Soc., Perkin Trans. 2 (1987) S1.
[22] L. Pauling, The Nature of the Chemical Bond, 3rd edn,
Cornell University Press, Ithaca, NY, 1960, p. 221.
[23] R. Bucourt, Top Stereochem. 8 (1974) 159.
[24] D. Cremer, J.A. Pople, J. Am. Chem. Soc. 97 (1975) 1354.
´
Acknowledgements
´
´
´ ´
¨
[25] A. Kucsman, I. Kapovits, I. Kovesdi, A. Kalman, L. Parkanyi,
J. Mol. Struct. 127 (1985) 135.
´
´
´
´
´
[26] A. Kucsman, I. Kapovits, L. Parkanyi, Gy. Argay, A. Kalman,
This work was supported by the Hungarian
Research Foundation (OTKA, No. T017187 and
FKFP 0165/1997).
J. Mol. Struct. 125 (1984) 331.