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First Sixfold Bridge-Formation in one Step.

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[4] We thank Prof. J . Seibl for the mass spectra.
[ S ] 6 - 8 had not been obtained in crystalline form up to now. Complexing
ability: V. Prelog et al., unpublished.
161 M. Nakazaki, Top. Stereochem. 15 (1984) lY9.
[7] 4 : C2: a = 15.47(1), b= I1.265(9), c = 15.220(4) A, p=91.54(5)".
1.20 for Z = 2 . 2474 measured reflections (Nonius
V=268I.9 A',
CAD4 diffractometer), 995 with F> 3 o ( F ) . Structure determined by direct methods (SHELX84), least-squares refinement. atoms with U,,,,>
0.055 refined anisotropically. Unit weighting, R =0.067.--5: P4,2,2;
a = 20.958(7), c = I 1.779(9)
V = 5 173.8 A', p '.,, r d = 1.26 for Z = 4 . 2932
measured reflections (Nonius CAD4 diffractometer), 1532 with
F > 2 0 ( F ) . Structure determined by direct methods (MULTANXO), leastsquares refinement, all non-H atoms anisotropic. Unit weighting,
R=O.O77.-DetaiIs for both crystal structures: M. Dobler et at., i n preparation.
[a] M. Dobler: fonophorer and (heir Srrucrures. Wiley, New York 198 I ; D. J.
Cram, K. N. Trueblood in F. Voglle, E. Weber (Eds.): Coneepr, Sinrcture
and Binding in Complexation in Host-guest Complex Chemistry, Springer.
Berlin 1985, p. 125.
[9] Yu. Ovchinnikov, V. T. Ivanov, A. M . Shkrob: Membrane A c m e Complexones, Elsevier, Amsterdam 1974.
[lo] W. C . Still, M . Kahn, A. Mitra, J . Ory. Chem. 43 (1978) 2923.
A,
Fig. I . Crystal structure of 4 .2CaHo along the crystallographic two-fold axis.
The benzene molecule drawn in the center lies 5.7 below the crown ether
ring. Important bond distances, bond angles, and torsion angles: spirobifluorene, six-membered ring 1.348 ... 1.435, average 1.387 A ; 117.0 ... 123.2",
average 120.0". Five-membered ring, single bonds 1.443,.. 1.556, average
1.513 A, angles(without angles at spiro atom) 106.5 ... I Il.h",average 109.7",
at spiro atom 100.2, 101.8". Angle between the best planes 91.3". 26-membered ring, values for the asymmetric moiety, beginning at the spiro atom:
distances 1.542, 1.348, 1.385, 1.540, 1.443, 1.407, 1.518, 1.438, 1.425, 1.506,
1.409, 1.384, 1.509A; angles 113.0, 126.7, 119.4, 120.2, 111.5, 111.6, 107.8,
108.1, 1 1 1.9, 114.9, 120.4, 117.8, 126.9": torsion angles 59.7,
172.9, 179.9,
-45.6, -70.5, 176.1,70.5, -177.7, -71.4, -32.1, -178.4, -17X.3,56.8°.
A
First Sixfold Bridge-Formation in One Step**
~
By Wolfram Kissener and Fritz Vogtle*
While threefold,"] fourfold,['] and fivefold"] bridging between two benzene rings in one step have all been successfully demonstrated in the past 15 years in the synthesis of
the phanes 1-3, the realization of a sixfold bridging, e.g.
to give the ten-membered "superphane hexasulfide" 4, in
one step has not proven possible, despite numerous effort~.['-~]
Fig. 2. Crystal structure of 5 .CH2CI2 along the crystallographic two-fold
axis. Important bond distances, bond angles, and torsion angles: spirobi116.3 ... 123.4",
fluorene, six-membered ring 1.354 ... 1.420, average 1.388
average 120.0". Five-membered ring, single bonds 1.500.. . 1.552, average
angles (without angles at spiro atom) average 109.6", at spiro atom
1.522
101.1, 101.4". Angle between the best planes 92.2". 32-membered ring, values
for the asymmetric moiety, beginning at the spiro atom: distances 1.552,
1.371, 1.398, 1.518, 1.402, 1.426, 1.486, 1.405, 1.443, 1.492, 1.414, 1.418, 1.569,
angles 117.4, 128.5, 118.5, 120.2, 109.7, 110.4, 107.5,
1.389, 1.373, 1.511
108.7, 114.2, 107.8, 115.2, 115.8, 111.7, 118.0, 117.4, 128.3"; torsion angles
45.5, - 178.8, 176.5, 36.2, 179.6, 172.3, -72.0, 174.3, - 173.8, 80.7, -69.6,
-64.2, 131.5, 176.7, 177.6, 59.3".
A;
A,
A;
[ M + K]' = 1307) 9,9'-spirobifluorene residues as intermediate or side products along with 27 mg of unreacted 2 .
Poly(9,9'-spirobifluorene) crown ethers 5 and 7 : Analogously, 5 . CH2C12
(439 mg) and 7 (62.5 mg) were obtained from a total of 1004 mg of 1 with
diethylene glycol.
Received: May 17, 1985 [2 1302 IE]
German version: Angew. Chem. 97 (1985) 793
We assume that all previous attempts at achieving this
aim have remained unsuccessful, not because of the number of bridges involved, but primarily because of the steric
strain. Working on this basis we have now found that even
six bridges can indeed be coupled intermolecularly if sterically less demanding starting materials are allowed to
react with each other using the cesium effect"' and dilution
principle. An example is the reaction of hexakis[3-(bromomethyl)phenyl]benzene 5[61with the corresponding hexathiol 6''' to give 7 .
Using a general procedure previously optimized by us in
earlier
this reaction resulted in precipitation of
the 22-membered polycyclic hexasulfide 7 as pale yellow
crystals (m.p. >320"C) in ca. 0.1% yield. The mass spec[*] Prof. Dr. F. Vogtle, Dipl.-Chem. W. Kissener
lnstitut fur Organische Chemie und Biochemie der Universitat
Cerhard-Domagk-Strasse I , D-5300 Bonn I (FRG)
[**I
[ I ] V. Prelog, D. Bedekovic, Helu Chim. Acfa 6 2 (1979) 2295.
[2] V. Prelog, S. Mutak, Helv. Chim. Acra 66 (1983) 2274.
[ 3 ] Phase-transfer catalysis ha5 already been used for the preparation of
crown ethers by P. DiCesare, B. Gross, Synrhesis 1979. 458; G. Coudert,
G. Guillaumet, M. Mpassi, rhid. 1985. 112.
794
0 V C H Verlag.~gese/kchafimhH, 0-6940 Weinheim, 1985
We wish to thank Prof. F. W. Rijllgen and DipLChem. S. S . Wong
(Bonn), Prof. H. Egge (Bonn), Prof. H. Hoberg and Dr. D. Henneberg
(Miilheim a. d. Ruhr), and Dr. G. Eckhardt (Bonn) for carrying out the
mass spectrometric investigations, Prof. H. irngarfinger (Heidelberg) for
performing crystallographic studies, and Dr. B. Sfejfan and Mr. C.
Schmrn (Bonn) for measuring the 400-MHr 'H-NMR spectra.
0570-083~/~S/0909-0794
$ 02.50/0
Angew. Chem. In!. Ed. Engl. 24 119851 No. 9
9
5 : X=Br
6 : X=SH
CH2X
7
With the synthesis of 7, it has been shown for the first
time that more than fivefold bridge formation is possible
in one step if steric factors are carefully taken into account. Owing to the “six-coordination of the benzene
ring”, the sixfold bridging, particularly with longer bridges
to give molecules with large cavities suitable for the encapsulation of organic guest molecules, opens u p novel aspects: According to model considerations, the cavity of 7
is, as it were, tailor-made for the accommodation of a benzene molecule, whereas longer, flexible bridges are
stretched after passage of the guest molecule; due to the
widening of the cavity the guest becomes “trapped”.
Received: May 6, 1985 [Z 1293 1E]
German version: Angew. Chem. 97 (1985) 782
trum ( m / z 1416 ( M + ) ) shows the molecular ion as an intense peak. The ’H-NMR absorptions of the previously
purified crystalline crude product are considerably broadened in CD2C12 as solvent. The polycondensation productl’l formed at the same time in the reaction, which is responsible for the broad signals, is removed by chromatography on silica gel with dichloromethane as eluent
( R , =0.61). The ‘H-NMR spectrum then shows a n AB system for the CH2 protons ( ~ 5 ~ = 2 . 6 5aB=3.2,
,
JAB=15 Hz)
and sharp signals at 6 = 6.85-7.05 for the aromatic protons
(in CD2C12).These findings are consistent with an all-anti
conformation for 7.Iy1It is easily seen on comparison with
the conformationally flexible 2-thia[3]ortho-terphenylophane 8,‘”’’that 7 can be fixed conformationally, due to
strain; according to model considerations the hexaphenylbenzene skeleton is present in a six-bladed propeller arrangement. This now raises the question whether 7 is sufficiently ridgid (and thus helical) in solution that it can be
separated into enantiomers. Analytical separation on
“Okamoto” resin‘”’ would indicate that this is indeed the
case.
The successful one-step sixfold bridging realized with 7
throws light on the reasons why 4 was hitherto unobtainable: The last CHzX groups in the intermediate 9 may no
longer achieve the conformation requisite for the sixth
bridging span.
CAS Registry numbers:
5, 952 16-95-5: 6, 97877-67-3; 7, 97877-68-4: thiourea, 62-56-6.
[I]F. Vogtle, Liebiys Ann. Chem. 735 (1970) 193; F. Vogtle, P. Neumann,
Chem. Commun. 1970, 1464.
(21 B. Klieser, F. Vogtle, Angew. Chem. 94 (1982) 632; Angew. Chem. f r r t .
Ed. Engl. 21 (1982) 618; Anyew. Chem. Suppl. 1982. 1392.
[3] P. Neumann. Di.ssertution, Universitat Heidelberg 1970; B. Schelcher,
Diplomarbeit, Universitat Bonn 1983: E. Koepp, Diplomarbeir. Universitat Bonn 1985.
[4] The six bridges of the known “superphane” were coupled in a multistep synthesis: V. Boekelheide, Top. Curr. Chem. 113 (1983) 89: V. Boekelheide in T. Lindberg (ed.): Strutegies and Tacrics in Organic Synrhesis, Academic Press, New York 1984, p. I : H. Hopf, S . El-Tamany,
Chem. Ber. 116 (1983) 1682.
[5] K. Meurer, F. Vogtle, A. Mannschreck, G. Stuhler, H. Puff, A. Roloff, J .
Org. Chem. 49 (1984) 3484.
[6] W. Kissener, F. Vogtle, Angew. Chem. 97 (1985) 227; Angew. Chem. Inr.
Ed. Engl. 24 (1985) 222.
[71 Prepared from 5 by the thiourea method. ‘ H - N M R (90 MHz), CDC13/
TMS int.): 6= 1.22 (t. S H ) , 3.3 (d, CH,S), 6.75 (s, aryl, m-H). MS: m / z
810 ( M + ) .
[S] The crystallinity of this product is remarkable; the product is possibly a
high-molecular-weight cyclic oligomer. Due to poor solubility, an osmometric molecular weight determination could not he carried out.
191 Cf. K. Bockmann, F. Vogtle, Chem. Ber. 114 (1981) 1065.
[I01 Cf. E. Hammerschmidt, F. Vogtle, Chem. Ber. 113 (1980) 1125.
[ I l l Cf. [6] and K. Meurer, A. Aigner, F. Vogtle, J . Inclusion Phmom. 3
(1985) 51. Due to solubility problems (cyclohexane/l% THF), difficulties were encountered in the preparariue separation of the enantiomers.
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