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Conformational Studies on Oxa Thia and Aza Derivatives of 7 8 13 14-Tetrahydrobenzo[1 2]cyclonona[5 6 7-de]naphthalene and 8H 15H-7 16-Dioxacyclodeca[1 2 3-de 6 7 8-de]dinaphthalene.

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This observation is consistent with conformations having C Z
symmetry. For the N-benzyl derivative ( 3 h ) two AB systems,
one for the 12-CH2 and 14-CH2 ring protons. and the other
for the z-benzyl protons, are observed at low temperatures.
Thus, the ground state conformation must have c ' 2 symmetry.
The 'H-NMR spectral changes (Table 1 ) indicate that inversion involving one observable conformation is clearly taking
place and the ground state conformation which has been
selected is the C , chair (7)r81. Strain energy calculations have
not been carried o u t because of the problems presented by
several heteroatoms. However, the C 2 chair conformation
(7) matches that selected by conformational analysis for
monocyclic cis-cis-I ,6-cyclodecadiene derivatives['!
"6,9,6" (2)[3,41,and "6,10,6" (3)r41systems by variable temperature 'H-NMR studies and collateral strain energy
calculations have encouraged the development of various complementary studies. These include the synthesis and cxamination of compounds ( 4 ) and ( 5 ) , in which an orrho-annelated
benzene ring of (2) [cf. also ( I ) and ( 3 ) ] is replaced by
a prri-annelated naphthalene residue.
my-zn
X-W
Received' July 15, 1974 [Z XOb IF]
German version: Angeu Chem 86. 813 (1974)
CAS Registry Numbers:
i2hJ. 30115-78-7. i2c.J. 31486-23-4: f 2 d J . 52810-62-5: 12e). 52810-63-6:
.
(21). 52810-64-7: ( 3 n ) , 52810-65-8; i 3 h ) . 52873-51-5; ( 3 ~ )52810-66-9:
f 3 d / , 52810-67-0: 140). 52810-68-1 : (4h). 52810-69-2: PBr,. 7789-60-8
.
.
[ I ] W D. 0lli.s and J . F Sroddurt, Angew. Chem. H6. R12 (1974). Angew,.
C'hem. intcrndt. Edit 13. 728 (1974).
I'[
G. Piiiu. E . C r c s w n z i , and G Bivcre. Tetrahedron 26. 57x9 (1970).
[ 3 ] E . D . Bi~rgmuririand Z. Pcidiowi~;, J. Amer. Chem. Soc. 75. 4281 (1923)
[4] U! tluhei-. J. Chem. Soc. 1931. 1765.
[5] J . F. Stoddrrrr in W D 0lli.s MTP lnternational Review of Science.
Organic Chemistry. Series One Butterworths. London. 1973, Vol I. p. I
[6] The notation for torsional angles iised in ( 5 ) and ( 6 ) refers in turn
to the 13a-13. 13-12, 12-11. 11-10a. 6a-6, 6-5, and 5-4a bonds. R . Crossiq.
-1. P. Doirnrny, M Nriqrddi. A. Brugo di, 0liic.iru. W D. Oilis, and 1. 0
S i ~ t / i d i i i i d 5, . C . S. Pcrkin I 1973, 105.
171 The c'? chair was found to be 6.5 kcdl/mol more stable than the C-.
twist-boat.
[XI The notation for torsional angles used in ( 7 ) refers i n turn to the
14a-14, 14-13. 13-12. 12-1 la, 7a-7, 7-6, 6-5, and 5-43 bonds.
[9] J . Drrlr, 7 E!w/und. and 7 S(hiriig. Chem. Commun. IYbH, 1477: H
L. Curl-ril. R W Roberts. J . Donohm,.and J. J . Ri//mc,r, J . Amer. Chem.
SOC. YO. 5263 (1968): B. W. Rohcrt.\. J . J . Vdliner, and K . S r r w , ;bid. YO,
5264 (19681: A Almmninyrn. C . G. Juiohsen, and H. M . Seip, Acta Chem.
Scand. 23, 1495 (1969): A. Friganhalrm and J . M . Lehn, Bull. SOC Chim.
Fr. IY09, 3724: J . Dule, Pure Appl. Chem. 25. 469 (1971): N . L. A/irngrr,
M. T Trihble. and J . T Sprague, J Org. Chem. 37, 2423 (1972); B. 19: Roberts.
J J Vollmrr. and K . L. Serris, J Amer. Chem. SOC. 96,4578 (1974).
[ 101 R. J . Ahruhum, L. J . K r i i k u , and
J. C. S. Chem. Comm.
A. Lrdirifh,
1973. 282.
Conformational Studies on Oxa, Thia, and Aza
Derivatives of 7,8,13,14-Tetrahydrobenzo[1,2]cyclonona [5,6,7-de] naphthalene and 8H , 15H-7,16-Dioxac yclodeca [1,2,3-de:6,7,8-d'e']dinaphthalene
By David J . Brickwood, W David Ollis,and J. Fraser Stoddart[']
Recent results on the definition of the conformational behavior
of hydrocarbons and heterocycles belonging to the "6,8,6"
( 4 . 7 1 ,I< = H;
(S), I t
= 11;
X = NTs;
Y = CIl2
x
Y
= CII2;
=
0
In the heterocycles ( 4 b ) , ( 4 c ) , (4f), ( 4 y ) , and ( 5 ) , we have
observed (Table 1 ) an AB system at low temperatures for
the ring methylene protons which coalesces to a sharp singlet
at higher temperatures. This observation may be interpreted
(Fig. I ) in terms ofa ring inversion process involving conformations in which the methylene groups are related either by
C , symmetry [chair C ( 7 ) or boat B ( 8 ) ] or by C 2 symmetry
[twist-boat TB (9)J Conformational analysis indicates that
the peri-interaction between the methylene groups of the 'ring
in the C ( 7 ) and B (8) conformations in compounds ( 4 b ) ( 4 9 ) is particularly large. This steric interaction is partially
relieved in the TB conformation ( 9 ) ; the principal nonbonded
interactions in ( 4 b ) , ( 4 c ) , (4f),and ( 4 g ) are between the
methylene groups of the ring and the heteroatoms (x = 0.NR').
We therefore propose that the TB conformation ( 9 ) is the
ground state conformation observed and that ring inversion
involves a TB+TB* pseudorotational process (Fig. 1 ). Three
observations support this proposal : (i) The magnitude of
the chemical shift differences (vA-vB) for the 7-CH2 and 14C H 2 protons is found (Tables 1 and 2) to depend significantly
upon the nature of the ring heteroatoms. There are a number
Table I . ' H - N M R spectral parameters (100MHz) and free energies of activation for ring inversion ( T B S T B * ) in
compounds ( 4 b ) . ( 4 f ) , ( 4 ~ ) (. 5 1 , and ( b h ) (K=coalescence temperature).
-
M.p.
Compound
Solvent
roc1
~
( 4 6 ) [a]
(4/J
125-127
(4Y)
15)
(6h)
2320
125--126
214-215
100--102
~
___-_ _ _ _ _
CDCI3-CSI (1:4)
CDC13
CDCI,
CDCIS-CS~ ( I :2)
CDCI,-CSz ( 2 : l )
Prochirdl
group
VA-VB
JAn
[Hz]
[Hz]
OCHz
33.0
24 1 .0
87.0
32.0
11.1
~
NCHI
NCH 2
OCHz
OCHz
~
____
28.6
-
14.0
13.0
10.7
10.0
[a] The singlet for the aryl methyl group in the 10-methyl derivative ( 4 c ) (m.p. 120-121°C)
- lOO"C,
-
-
-
AG' at K
[kcal/mol]
~
194
303
330
199
212
- ~ -
9.5
14.0
15.9
9.7
10.4
- - ---
remains sharp down to
thus indicating the absence of exchange between diastereomeric conformations.
-
[*] Dr. D. J. Brickwood, Prof. Dr. W. D. Ollis, and Dr. J. F. Stoddart
Department of Chemistry, The University
Sheffield 53 7 H F (England)
Angew. Chum. internal. Edit. J Vo1. 13 (1974)
~
&
[K]
J No. I f
of examples[51of van der Waals interactions between heteroatoms and proximate protons which lead to deshielding of
the proton involved. The expectation['] that the deshielding
731
Table 2. ’H-NMR spectral changes (I00 MHz) and activation parameters for compounds 1 4 d ) and f 4 e ) .
__~---_____
__.___-.___
Campound
M.p.
rC]
Solvent
(4d)
195-197
CDCI3:CSI
(2: I )
T
Group
[“C]
--___
Chemical shifts I T ) [a]
Coupling constants [Hz]
___-___-__
(41))
272--274
-51
SCH2
CDCI,
-33
+37
-55
+30
ArCH,
-_____-_
Sites
involved in
exchange [a]
__
*
AG
[kcal/mol]
~
Process
Relative
populations
PI
P2
4.51 (Al), 5.72 (B1) [b], J 12.0
5.15 (AZ), 5.53 (B2). J 14.0
4.50 (A12). 5.73 (B12), J 12.0
5.12 (AB12)
7.62 (A), 8.08 (B)
8.01 (AB)
AI-A2
B1 -B2
13.3
TB-C
0.86
0.14
AISBI
A-B
B-A
13.7
12.6
13.2
TB=TB*
C-TB
TB-C
0.80
0.20
[a] Sites are designated (A) and ( B ) for uncoupled two-site systems; sites that represent two time-averaged signals are designated IAB). Sites are (Al). (BI),
(A2). and (82) for four-site systems where there is coupling i n the form of two AB systems. Sites that represent two time-averaged signals are designated
(AB1) [average of ( A l ) and (BI)] and A12 [average of (A!) and (A2)] erc.
[ b ] v ~ ~ - v R I = I ~ Hz.
I
influence of heteroatoms will be related to their polarizabilities
is also fulfilled by the data recorded in Tables 1 and 2; ( i i )
when the heteroatoms are both sulfur as in ( 4 d ) and ( 4 e ) ,
then transannular nonbonded interactions with the methylene
groups of the ring destabilize the TB conformation ( 9 ) sufficiently to permit the observation of approximately 20% of
a second conformation at low temperatures (Table 2). This
minor conformation is presumably the C conformation ( 7 ) ;
jiii) the fact that the free energies of activation for the dithionins [( 4 d ) and ( 4 e ) ] and diazonins [ ( 4 f ) and ( 4 g ) ] are
larger than those for the dioxonins [ ( 4 b ) and ( 4 c ) ] is consistent with the pseudorotational process shown in Figure 1,
where the folded-boat (FB) conformations [ ( l o ) and (1I ) ]
correspond to the transition states. The main component of
strain in these FB transition states must arise from nonbonded
interactions between the methylene groups of the ring and
the heteroatoms (X = 0, S, NR’).
@ $2&;o
Y-
-x
\ /
Y-x
c (-+-+-+)
c* (+-+-+-)
B (-++--+)
B* (+ - -++ -)
(71
(8)
T B (+-++-+)
TB* (-i--+-)
191
(Table 1) in the dioxonin ( 5 ) , and in the dioxecin (6 b ) ,
also lead to very similar conclusions. The conformational
itinerary of compounds ( 5 ) and ( 6 b ) also involve ring inversion (TB$TB*) between enantiomeric twist-boat conformations.
Received: July 15. 1974 [Z 8Oc I € ]
German version: Angew. Chem. 86,814 (1974)
CAS Registry Numbers:
( 4 h ) . 33296-36-5; ( 4 c ) , 52826-30-9; (4d), 52826-31-0; (4e). 52826-32-1 :
(4J). 52826-33-2: 149). 52826-34-3 ; (51, 52826-35-4; ( 6 b j . 52826-36-5.
[I] R Crossiry. A . P. Downing, M . Nopadi, A. Bruyu
Ollis, and I . 0. Surhrrlunr1, J. C . S. Perkin I IY73, 105.
C/P
Oliwim, W D.
[2] M. Monreculco, M . Sf. Jacques. and R Wusi./ishm, J. Amer. Chem.
SOC.95, 2023 (1973). D.J . Brickwood, W D.Olliv, and J. f. Sioridurr. unpublished results: W D. 0llis and J . F . Sroddarr, J. C. S. Chem. Comm. 1973.
571: A. Saundrrs and J . M . Sprakr. J. C . S. Perkin I1 1972, 1660.
[3] W: D. Oilis
Chcm. internat.
[4] W D. Ol1i.s
Chem. internat.
and J F. Srorlrturi, Angew. Chem. 86, 812 (1974): Angew.
Edit. 13, 728 (1974).
and J. F . Sioddrrrr, Angew. Chem. X6, 813 (1974): Angew
Edit. 13, 730 (1974).
[5] S. Winsrein. P . Curter, F . A L Anc2.i. and A J . R. Bourn, J. Amer.
Chem SOC. 87, 5239 (1965): C. R. Johnson and D C. Vrgh, Chem. Commun.
1969. 557: 7. Saro and K . Uno, J . C. S. Perkin I IY73, 895.
[6] L. M . Jockmun and S. Sfrrnhrll- Applications of Nuclear Magnetic
Resonance Spectroscopy to Organic Chemistry. Pergamon, London 1969.
p. 71.
a‘yyxb
\
,/Y A X \ /,-
FBI (0-+O-+)
FBI* (o+-o+-)
FB‘L (+-0+-0)
FBP( - + o - to )
FU I
I
J
TB-~
f
TB
“-FBZ
FB~*
,
Fig. I . Conformational changes in compounds ( 4 6 1 , ( 4 c j . ( 4 J i . 1 4 g i , and
( 5 ) . The notation [ l ] for torsional angles refers in turn to the 6a-7, 7-8.
8a-8, I2a-13, 13-14, and 14-14a bonds.
Similar considerations of chemical shift differences between
the diastereotopic methylene protons (HA and HB) and the
values of the free energies of activation for ring inversion
732
A Heptalene Synthesis from 1,6-Methano[lO]annulene;
Evidence for a Fast n-Bond Shift
By Emanuel Vogel, Heinrich Konigshofen, Jiirgen Wassen, Klaus
Miillen, and Jean F. M. Oth[*]
Heptalene ( l ) , which like its homolog pentalene1’] has long
been the subject of theoretical study, was synthesized by
Dauben and Bertelli[” in 1961. However, it remained poorly
accessible and to this day the bonding of the hydrocarbon
has still not been thoroughly characterized by experimental
means. Recent quantum mechanical calculations[31indicate
that the heptalene structure having delocalized x-bonds ( D 2 h
molecular symmetry) is destabilized by comparison with the
structure possessing alternating bonds (C, symmetry). By ana-
[*I Prof.
Dr. E. Vogel, Dr. H. Konigshofen, and Dip].-Chem. J. Wassen
Institut fur Organische Chemie der Universitat
5 Koln I. Ziilpicher Strasse 47 (Germany)
Dr. K. Mullen and Prof. Dr. J. F. M. 0 t h
Laboratorium fur Organische Chemie der
Eidgenossischen Technischen Hochschule
CH-8006 Zurich, Universitatsstrasse 6/8 (Switzerland)
Angew. Chem. internat. Edir.
1 Yol. I3
(1974) 1 No. 11
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conformational, thia, naphthalene, 15h, cyclonona, tetrahydrobenzo, dioxacyclodeca, oxa, dinaphthalene, studies, aza, derivatives
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