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An Optically Active Tribenzoxepin.

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Without overqualifying our predictions, other than to
observe that they are not so fanciful as they might
seem, we suggest that it might be possible to synthesize
molecules (11)-(16).
These molecules are all related to the as yet unknown
2-thia(1v)-isopropylidene diacetate, (CH&S(OAC)~,
just as (9) and (i0)are related to the known phenyliodonium diacetate C ~ H ~ I ( O A CThe
) ~ . fact that (9)
and (10)are so unusually stable to decomposition by
boiling water, as compared with the relative instability
of C ~ H ~ I ( O A Cwould
) ~ , argue for the likelihood of
stable molecules (Ii) -(16) even though the corresponding diacetate might be sufficiently reactive as to
be not isolable. From Tables 1 and 2 it seems likely
that sulfur will form H V bonds to OC(0) groups, and
if for some reason this does not actually occur, it will
surely occur for S replaced by Se or Te. It should be
noted that (11)-(14) will be optically active and there
seems to be little likelihood of unimolecular racemization (cf. Section 5); molecule (14) is fixed with a
bridge so as to prevent racemizationl451.
1451 K. Mislow, private communication.
8. Conclusion
An attempt has been made to place the molecules and
ions formed from atoms using their higher valences in
a unified scheme through a detailed but simple theoretical description of hypervalent bonds. From the
discussion it is evident that such a description is
eminently reasonable and that there are numerous
implications for the chemistry of these hypervalent
molecules but that the experimental information
necessary for a proper understanding of their physicochemical behavior is lacking. It is hoped that the
present studyC461, which does not intend to provide
the final answers to such questions as mechanisms of
inversion, synthetic paths, and the existence of unusual
new molecules, will at least stimulate further consideration of this very interesting, but until now highly
neglected, field of chemistry.
I am deeply indebted to numerous cofleagues for their
patience in discussing these ideas over the past several
years. I am particularly indebted to E. J. Corey, P.
Laszlo, R. Mechoulam, and my father, S. Musher, without whom these ideas might never have crystallized.
I would also like to thank W . C. Agosta and H. K.
Livingston who successfully synthesized the first H V
molecules to be inspired by the present study in the
course of their varied research programs. The manuscript was drafted while I was a guest at the Weizmann
Institute of Science, Rehovot, Israel, in the summer of
1964, and the final version was completed at the same
Institute this past summer. I am grateful for the kind
hospitality shown me there by S . Lifson, D.Samuel, and
their colleagues.
Received: June 20, 1968
[A 677 IE1
German version: Angew. Chem. 81, 68 (1969)
[46] R. J. Gillespie, Angew. Chem. 79,885 (1967); Angew. Chem.
internat. Edit. 6, 819 (1967); R . F. Hudson, Angew. Chem. 79,
756 (1967); Angew. Chem. internat. Edit. 6, 749 (1967). The
reader's attention should aiso be directed to the numerous
studies on hypervalent molecules by Hellwinkel et al., e.g. D.
Hellwinkel and G. Fahrbach, Chem. Ber. 101,514 (1968).
COMMUNICATIONS
An Optically Active TribenzoxepinI**I
By W. Tochtermann and C.Franker*]
Optically active I-methyltribenzoxepin-3-carboxylicacid
(3b) has been prepared as a model substance for a study of
the intramolecular mobility of boat-shaped seven-membered
rings 111since the energy barriers for conformational inversion
are often relatively low in oxygen heterocycles [21.
The dibromocyclopropane derivative ( I ) was obtained from
1,4-epoxy-1.4-dihydro-1,4-dimethyltribenzoxepin
[31, bromoform, and potassium tert-butoxide in benzene at 25 "C, the
yield being 31 % after chromatographic separation from unchanged starting material on A1203 with CC14 and CHC13; it
had m.p. 184-186°C (from cyclohexane) and a 1H-NMR
spectrum (in CDC13) [41 T = 2.5-2.9 (8 H, M), T = 7.53 (2H, S),
T = 8.05 (6H, S). When heated for 48 h at 100 O C with silver
sulfate (molar ratio 1 :1.4) in 2 N HzSO4/dioxane (1 :2 v/v) it
afforded directly [51 3-bromo-1-methyltribenzoxepin (3n)
68
133% yield; m.p. 114-116°C (from cyclohexane); 1H-NMR
spectrum (in CDC13), T = 2.3-3.0 (lOH, M), T = 7.57 (3H,
S)] as well as the cycIopropyI-ally1 rearrangement product
( 2 ) (44% yield; m.p. 211-212OC). The product (2) was isolated by recrystallization of the crude product from CC14;
chromatography of the mother liquors therefrom on A1203
with CC14 gave pule (3a). Polyphosphoric acid converts the
alcohol (2) into (3a) in 30% yield in 2.5 h at 130°C.
The same process can be used for preparation of 3-bromo-lmethyl-9If-tribenzo[a,c,e]cyclohepten-9-one[(3a), C=O in
place of 01, which can be reduced to the known l-methyl9H-tri benzo [n,c,e]cyclohepten-9-ol by LiAlH4 [GI.
The action of n-butyllithium in light petroleum on (3a) at
-SO "C in tetrahydrofuran and subsequent carboxylation
affords the carboxylic acid (36) 180% yield; m.p. 220-222 "C
(from benzene)], whose structure is proved by elemental
analysis and IR and 1H-NMR spectra [CDC13: carboxyl
proton at T = 0.2; AB system at T = 1.80 and 1.92 with JAB =
1.8 Hz (H4, HZ), T = 2.2-3.0 (8H, M), T = 7.48 (3H, S)].
Anxew. Chem. internat. Edit.
Vol.8 (I969) J No. I
- +
R'
(3a), X = B r
(3b), X = COOH
Keeping equimolar amounts of (3b) and brucine in ethanol/
methanol (1 :1-1 :2 v,'v) for some time gives a 60 % yieldC71 of
a crystalline brucine salt that shows rapid mutarotation in
acetone at 20.5 OC ( t y 2 = 200 sec; extrapolation of the specific
rotation to to gives [ C C ] : ; ~ = +87 O, changing to -43 O, c =
0.013g/ml). The dextrorotatory acid can be obtained by
dissolving this salt as fast as possible in acetone at -2OOC
and precipitating it rapidly with 2N HCI.Solutions of (+)(3h) in acetone racemize at +20.5 "Cwith a half-life period
of 195 sec; [o(]::b5 was +135" after 105 sec (extrapolated
to to: [a]::k5 = +190 O, c = 0.02 g/ml). Thence the free enthalpy
of activation for ring inversion of (3b) is calculated to be
AG.$,, = 20.8 kcal/mole, i.e., (36) is much more mobile than
comparable systems 111.
Received: October 23, 1968
[ Z 893 IE]
2
2
2
2
2
2
2
2
I R
B.p. ("Cltorr)
M.p. ("C)
128/0.3 Id]
64-65
82-83
133
108-109/0.4
90-92/0.3
90-92/0.3
64-64.5
165-170/0.3
178- 180/0.3
118-119
79-80
3
3
3
3
2
2
2
2
[a] Also CH3 o n C-2.
[b] Also CH3 o n C-3.
[ c ] N M R spectrum in CDCI3 (TMS as internal standard): T = 6.03
(Heq on C-2), 7.36 (Hax on C-2). 8.1-8.8 (4H on C-3 and C-4), 7.45
(Heq o n C-5). 7.07 (Hax on C-5), 8.05 (2H on C-8). 7.61 (2H on C-9),
8.7 (CH,); Varian A H 100 and 220 instruments. IR spectrum in KBr:
broad band at 1630 cm-1 (lactam).
[d] M.p. of the hydrochloride 178--179°C.
For the synthesis of (3) a y-or 8-keto acid o r an ester thereof
is treated in an inert solvent with a 1.2-, 1,3-. o r 1,4-alkanediamine at 10O-15O0C.
German version: Angew. Chem. 81, 32 (1969)
[*IDoz. Dr. W. Tochtermann and C. Franke
Organisch-Chemisches Institut der Universitat
69 Heidelberg, Tiergartenstrasse (Germany)
[**I This work was supported by the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie.
[l] W. Tochtermann, C. Franke, and D . Schafer, Chem. Ber. 101,
3122 (1968).
[2]K . Mislow, M . A. W . Glass, H . B. Hopps, E. Simon, and G. H .
Wahljr., J . Amer. chem. SOC.86, 1710 (1964);R. K . Harris and
R. A . Spragg, J. chem. SOC.(London) B 1968, 684; further references are given there; for the mobility of oxepins see E. Vogel
and H . Giinther, Angew. Chem. 79, 429 (1967);Angew. Chem.
internat. Edit. 6, 385 (1967);H . Ciinther, R. Schubart, and E.
Vogel, Z . Naturforsch. 22b, 25 (1967).
[3] W . Tochtermann, K . Oppenlander, and M . Nguyen-Duong
Hoang, Liebigs Ann. Chem. 701, 117 (1967).
[4]All spectra were determined with TMS as internal standard
on a Varian A-60 instrument.
[5] For a discussion of this reaction sequence see ref. [I].
[6] W. Tochtermann and D . Schafer, unpublished work; W .
Tochtermann and K . Stecher, Tetrahedron Letters 1967, 3847.
[7]A second order asymmetric transformation is indicated in
this case; weakly dextrorotatory (36) was obtained from the
mother liquors of the brucine salt.
Synthesis of ortho-Condensed qy-Diazabicyclanes
Containing a Bridgehead Nitrogen Atom
5-Methyl-I,4-diazabicyclo [3.3.0]octan-8-one(3a) :
Ethyl levulate (100 g) is heated with ethylenediamine (150 g)
and ethanol (200 ml) for 8 h at 130-140 "C.On evaporation
and distillation in a vacuum the product ( 3 a ) (83.5 g), b.p.
108-109 OC/0.4torr, can be isolated. Its structure is proved by
the following spectroscopic findings [31: N M R spectrum in
CDC13 (TMS as internal standard): T = 6.43 (H on C-2).
7.07 (H'o n C-2). 6.81 (Hon C-3),6.77 (H'on C-3), 7.83 (H
on C-6), 7.97 (H'on C-6). 7.24 (Hon C-7), 7.63 (H'o n C-7).
8.7 (CH3); I R spectrum in CC14: 1700 cm-1 (lactam).
Received: October 23, 1968
[ Z 892 IE]
German version: Angew. Chem. 81. 34 (1969)
[*] Dr. H. Wollweber
Pharmazeutisch-Wissenschaftliches Laboratorium
der Farbenfabriken Bayer AG, Werk Elberfeld
56 Wuppertal-Elberfeld, Postfach 21 (Germany)
[l] R . Adams and 1. J. Pachter, J . Amer. chem. SOC.74, 4907
(1952); C. A . Grob, H. P. Fischer, H . Link, and E. Renk, Helv.
chim. Acta 46, 1194 (1963).
121 G . Westphal and H. H. Stork, 2. Chem. 7, 456 (1967).
[3]I wish to thank Dr. W . Naegele, Dr. J . Kurz, and Dr. W .
Geiger for recording and discussing the spectra.
By H . Wollweber [*I
Two New Valence Isomers of [lZIAnnulene
ortho-Condensed a,y-diazabicyclanes such as ( I ) , being
formaldehyde aminals, are unstable to acids. Only introduction of at least one 0x0 group next to one of the nitrogen
atoms is expected to stabilize derivatives to acid. The compounds (2) 111 and ( 4 ) [21 have been obtained previously.
The expected stability to acids has now been observed also
for compounds of type ( 3 ) , which moreover are now readily
accessible.
Angew. Chem. internat. Edit.
/ Vol. 8 (1969) / No. I
By G. Schroder, W. Martin, and H. Riitteler*l
We report here two new valence isomers of [12]annulene, a
compound that has not yet been detected[lJ], namely, cis,
anti,cis-tricyclo[6.4.0.O~~~]dodeca-3,5,9,1l-tetraene
(dimeric
benzene) (2) and trans-bicyclo[6.4.0]dodeca-2,4,6,9,ll-pentaene (trans-4a,l0a-dihydrobenzocyclooctene)(3).
69
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