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Selective Inclusion of Uncharged Guest Molecules by Neutral Hosts with Fence-Shaped Side Arms.

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the chiral center (Table 1). Open chain hydrocarbons are
generally oxidized somewhat slower than alicyclies by
peroxycarboxylic acids so that radical side reactions can
take place in certain circumstances.
Table 1. Hydroxylation of alkanes RH and aryl- or cyclopropyl-substituted
alkanes [a].
ci'
4 c -c-c
H
1
-< -('-c-c-c
Received: September 9, 1981 [Z 981 IE]
German version: Angew. Chem. 94 (1982) 153
(yC-c-c-c-c
5
FI
RH
Conversion [%]
tert-ROH
1
43
49
57
33.5
15.5
77
84
93 Icl
85 [dl
71
2
3
4
5
Polar substituents such as chlorine in 11 and 12, which
only exert inductive effects within the substrate and cannot
deactivate the peroxy acids, again yield normal hydroxylation products. The reduced rate observed with y-halogen
substituents ( l l ) ,and to a much lesser degree with &halogen substituents (12) is in accord with the electrophilic
character of the reaction"]. The observed stereospecificity,
however, is at variance with carbocationic intermediates of
longer lifetime.
[O/o]
k / k , [bl
13
20
23
23
53
After 24-48 h <4Oh conversion
CAS Registry numbers:
1 107-83-5; 2 96-14-0; 3 592-13-2; 4 2051-30-1; 5 4292-92-6; 6 98-82-8: 7
135-98-8; 8 4410-75-7; 9 1603-61-8; 10 5685-47-2; 11 (X=H) 78-78-4; 11
(X=CI) 107-84-6; 11 (X=OOCCH>) 123-92-2; 11 (X=OH) 123-51-3; 12
(X =CI) 62016-94-8; 12 (X = OCHs) 3590-70-3; 2-methyl-2-pentanol 590-363: 3-methyl-3-pentanol 77-74-7; 2,5-dimethyl-2-hexanol 3730-60-7: 2,6-dimethyl-2-octanol 18479-51-7; (-)-3,I-dimethyl-3-octanol80558-38-9: I-( I-penty1)cyclohexanol 30101-37-2.
[ I ] a) W. Miiller, H.-J. Schneider, Angew. Chem. 91 (1979) 438; Angew.
Chem. Int. Ed. Engl. 18 (1979) 407; b) H.-J. Schneider, N. Becker, K.
Philippi, Chem. Ber. 114 (1981) 1562.
(21 a) R. Liotta, W. S. Hoff, J. Org. Chem. 45 (1980) 2887: b) H. Hart, Acc.
Chem. Res. 4 (1971) 337.
131 D. Swern: Organic Peroxides. Vol. 2, Wiley-Interscience, New York 1971,
p. 450ff.
[4] Y. R. Naves, Helu. Chim. Acta 29 (1946) 1450.
~~
[a] In CHCI? (reflux) or at 60+5"C (1, 2), RH: p-nitroperoxybenzoic acid
1 : 1 or 1 :2 (3). 30-36 h or (5) [RH]=0.7--1.4 mol/L. [b] Ratio of the hybonds (prerequisite: attack at
droxylation rates of terf- and sec-C-H
CH,< 1%). [c] 91% Mono-, 9% dihydroxy-product. [d] 38% 2-, 62% 6-hydroxy
compound (Id];;= -0.909, ref. [4]: Id]:;= -0.78 (neat)).
In contrast to their reactions with peroxytrifluoroacetic
acid['] substituted arenes (cf. 6- 9) are remarkably inert
towards p-nitroperbenzoic acid; exeptions are only very
reactive compounds such as mesitylene. Moreover, aromatic substituents even prevent attack at tertiary C-H
bonds which are separated by several bonds from the n
system (see compounds 8, 9). This is explained by the
H-bond acceptor properties of arenes, which is known to
reduce the reactivity of peracids in the Prileschajev reaction"].
Similarly, oxygen substituents, which act has H-bond acceptors, lead to diminished reactivity of the substrate. This
is visible in the small yields of diols obtained from alkanes
where the tertiary C-H bonds are far removed from the
oxygen (3,4),or with acetoxyalkanes (Table 2). With primary hydroxy or methoxy derivatives only products from
the oxidation of C-H bonds in a-position to the oxygen
substituent are obtained.
Table 2. Hydroxylation of heterosubstituted alkanes [a].
c
cI
c-c-c-c-c-x
11
A
H
11, x =
kx/ktl
12,
x=
kx/kH
12
H
1.oo
CI
0.06f 0.01
OOCCH,
0.06 & 0.02
H
I .oo
CI
0.77f0.05
OCHs [c]
< 0.05
OH [bl
< 0.05
[a] Rate constants relative to 11 and 12 (X=H), from competition reactions
followed by NMR analysis of the product. [b] Main products: 3-methylbutanoic acid (50%) and its ester (5%); ten-hydroxylation product < 5%. [c] Main
products: 4-methylpentanoic acid (43%), 4-methyl- I-pentanol (14%).
Angew. Chem. Inr. Ed. Engl. 21 (1982) No. 2
Selective Inclusion of Uncharged Guest
Molecules by Neutral Hosts with
Fence-Shaped Side Arms""
By Fritz Vogtle* and Walter M . Muller
Dedicated to Professor Heinrich puff on the occasion
of his 60th birthday
As already observed more than 25 years ago"], benzene
and other lipophilic guest molecules appear to be intercalated in the cavities of synthetic guest molecules; however,
a generalization of this type of host-guest
has not yet been achieved.
We have furnished multimembered monocycles with
side arms, in such a way that a versatile enclosed molecular
cavity for the up-take of organic guest molecules can be
formed. The substituents fulfill the function of a molecular
fence@];their number and size are determined by the number of ring members. Space filling models of compounds
of this type such as l b show that according to this general
concept, large spherically shaped molecules should be accommodated. The advantages over polycyclic large-ring
cage
are the straightforward synthesis of the
monocycles and the easier adaptability to potential guest
molecules caused by the conformational mobility of the
framework and its arms.
For the synthesis of 1 and analogous cavity molecules 2
and 3, N,N'-dibenzyl- or N,N'-dimethylethylenediamine
were allowed to react under conditions of high dilution
with the corresponding dicarboxylic acid dichlorides (terephthalic-, 4,4'-biphenyl, o-terphenyl-4,4"-) to give, respectively, the hexa- or tetracarboxylic acid amides, which can
[*] Prof. Dr. F. Vogtle, W. M. Miiller
[**I
Institut fur Organische Chemie und Biochemie der Universitat
Gerhard-Domagk-Strasse I, D-5300 Bonn 1 (Germany)
This work was supported by the Deutsche Forschungsgemeinschaft. Frl.
U. Werner is thanked for assistance with the experimental work.
0 Verlag Chemie GmbH. 6940 Weinheim, 1982
0570-0833/82/0202-0147 $ 02.50/0
147
R
R
pound 3, which also contains two biphenyl units, but in
which CH2 and N have changed places and-in the sense
of our concept-substituents on nitrogen are present. This
host molecule is able to stoichiometrically bind penta- and
hexafluorobenzene, but not, however, benzene, cyclohexane, dioxane, and fluorobenzene.
We conclude that novel inclusion compounds between
uncharged organic molecules can be tailor-made according
to this principle.
Received: September 28, 1981 [Z 999 IE]
German version: Angew. Chem. 94 (1982) 138
The full manuscript of this communication appears in:
Angew. Chem. Suppl. 1982, 185-192
be reduced to the polyamines with B2H+ Apart from the
trimer l b (20% yield, m.p. 176--178"C), the dimers 2b
(12%, 163--165"C), 2c (18%, 158--162"C), or 3 [30%,
glassy, G(benzy1-H)= 3.55, G(ethano-H)=2.61, in CDCI,],
lower and higher oligomers, which were separated chromatographically, are formed.
[ I ] H. Stetter, E.-E.Roos, Chem. Ber. 88 (1955) 1390; G. Faust, M. Pallas, J.
Prakt. Chem. I 1 (1960) 146.
121 For calixarene-clathrate formation cf. C. D. Gutsche, B. Dhawan, K. H.
No, R. Muthukrishnan, J . Am. Chem. SOC. 103 (1981) 3782; C. W. Schimelpfenig, R. R. Ford, J. Org. Chem. 46 (1981) 1210.--Guest molecules in
cationic hosts: K. Odashima, A. Itai, Y. litaka, K. Koga, J . Am. Chem.
SOC.102 (1980) 2504.
[3] Host-guest interactions in solution: Y. Murakami, A. Nakano, R. Miyata,
Y. Matsuda, J. Chem. SOC.Perkin Trans. I 1979. 1669: cf. 1. Tabushi, Y.
Kimura, K. Yamamura, J . Am. Chem. SOC.103 (1981) 6486.
[4] F. Vogtle, Chimia 33 (1979) 239; 35 (1981) 483; F. Vagtle, H. Sieger, W.
M. Miiller, Top. Curr. Chem. 98 (1981) 107.
[6] Cf. in this context "tailed picket fence and picket fence porphyrins'.: J. P.
Collman, Ace. Chem. Res. 10 (1977) 265.
q5-Cyclopentadienyl(qs-l,3-diborolene)cobalt -
A Novel Type of Sandwich Complexes
with a Pentacoordinated Carbon Atom **
By Walter Siebert*, Joseph Edwin, and
Hans Priizkow
Whereas previous attempts to include uncharged organic guest molecules into l b have been unsuccessful, recrystallization of the 32-membered ring compound 2b
from cyclohexane produced crystals, which after drying for
24 h at 50°C/12 torr occur as a 1 :1 complex (93% yield,
m. p. = 84-90 " C and 163-165 "C (recrystallized twice)
'H-NMR, elemental analysis). Cyclohexane was tenaciously retained, as were also dioxane. tetrahydropyran,
and morpholine even after extended drying (1 5 h) at 50 C /
12 torr.
In contrast, the molecules methylcyclohexane, cycloheptane, cyclooctane, decalin, and tetralin, as well as benzene
and toluene, which only differ slightly in spacial requirement are not retained in a similar manner, Recrystallization of 2b from a 1 : 1 benzene/cyclohexane mixture yields
only the cyclohexane complex, thus opening u p a separation mode for benzene and cyclohexane. Likewise, mesilylene adheres to a lesser extent than cyclohexane: for a few
hours at 20°C in vacuo; after a longer time it is removed
without residue.
Although only X-ray structural analyses finally will indicate an "intramolecular" guest inclusion, or the not less interesting inclusion in the host lattice, the precise stoichiometry and selectivity of the guest up-take might indicate the first reported host-guest complexation.
Attempts at complexing with 2c, in which the benzylare replaced by methyl-groups, did not lead to formation
of inclusion compounds. This indicates the influence of
the appropriate side arm on the host-guest interaction.
In order to investigate whether the Stetter complex"]
could be the first representative of a systematic host-guest
chemistry, we studied the likewise 28-membered ring com148
0 Verlag Chemie GmbH. 6940 Weinheim. 1982
During the synthesis of the paramagnetic triple-decker
sandwich complex 3a"l from the A4-1,3-diborolene l a and
dicarbonyl(q5-cyclopentadienyl)cobalt we found traces of
the red mononuclear complex 2a. Our hypothesis that the
dinuclear complex 3 is formed by "stacking", from the
sandwich 2 and a (C5Hs)Co fragment, has now been confirmed by the reaction of $-cyclopentadienylbis(ethene)cobalt'21with l b via 2b (65% yield, b.p. 70°C/
0.01 torr, m.p. 62°C) to give the triple-decker 3b (54%
yield). 2a can be prepared in an analogous way from laf3'
in petroleum ether (PE) (48% yield, m. p. 92 "C).
'R
la: R = CZH5, R' = CH,
I b R = CH,, F? = H
2a
2b
The constitution of these novel sandwich complexes follows from analytical and spectroscopic data: In the mass
[*I Prof. Dr. W. Siebert, Dr. J. Edwin
Fachbereich Chemie der Universitat
Hans-Meerwein-Strasse, D-3550 Marburg I (Germany)
Present address: Anorganisch-chemisches lnstitut der Universitat
Im Neuenheimer Feld 270, D-6900 Heidelberg 1 (Germany)
Dr. H. Pritzkow
Anorganisch-chemisches lnstitut der Universitat Heidelberg (Germany)
[**I Diborylethylene Compounds as Ligands in Metal Complexes, Part 1 I .
This work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen 1ndustrie.-Part 10: W. Siebert, H. Schmidt,
R. Full, Z . Naturforsch. B 35 (1980) 873.
0570-0833/8.?/0202-0l48 $ 02.50/0
Angew. Chem. Inr. Ed. Engl. 21 (1982) No. 2
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