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Complex Bonding of a Vinylcyclopropane Group of Bullvalene to a Transition Metal via a -Allyl and a Component.

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obtained, the complete structure (Fig. 1)could be derived from
two Fourier syntheses. The atomic parameters were subjected
to isotropic full-matrix refinement by the method of least
squares until an R factor of 9 % was reached. At this stage the
following features became apparent (see Fig. 1):
a) In (1) the dihedral angle C2'-C1'-N1-C6[31 is -80" (ie. the
bond N1-C6 is rotated by 80" in an anticlockwise direction with
respect to the bond Cl'-C2'). Hitherto, all pyrimidine nucleosides apart from 4-thiouridine have been found to have this
anti
in which the 0 2 atom points away from
the sugar.
(3)151 and methylenecyclopropane[6] form stable z-allyl-palladium complexes, apparently by ring opening of the postulated
edge-coordination complexes[']. The action of Fe2(CO), on
cyclopropylstyrene[*] and spiro[2.4]hepta-4,6-dienet9I furnishes substituted diene-Fe(C0)3 complexes. Manganese,
rhenium, iron, and iridium have been reported to give very
stable cyclopropylcarbonyl complexes, the manganese compound affording a n-ally1 derivative on decarbonylation[l'!
The present communication reports on the first example (2)
of complex formation by a vinylcyclopropane group (3) Via a
n-ally1 and a o component (4) with a Fe(C0)3 unit.
b) As in 4-thiouridine, 3'-O-a~etyl-4-thiothymidine[~],
2,4dithiouridineL6], and 1-methyl-4-thiouracil [71, the 4-thiouracil
residue is in the keto, keto form. The atoms of the heterocycle
are substantially coplanar.
c) In nucleosides the sugars usually have an "envelope" configuration with C2' or C3' displaced about 0.5 A from the plane
through the other four atoms of the five-membered ring. In
the arabinose present in ( I ) , C3' is about 0.6 A away from the
plane and on the same side as C5' - the sugar residue thus has
the C3'-endo conformation.
The cis-diol group in ribosyl residues of comparable C3'-endo
conformation has a dihedral angle 02'-C2'-C3'-03', of about
+50".In the arabinose residue, however, this angle is about
-80", i.e. the C3'-03' bond is rotated in an anticlockwise
direction relative to the C2'-02' bond.
The dihedral angle NLCl'-C2'-02' is also an important factor
in any comparison between the structures of the ribose and the
arabinose residues. In the C3'-endo ribonucleosides this angle
isabout -140"; however,in(l)itisonIy-Z9",te. intheformer
case the C1 '-Nl and C2'-02' are "trans"(tran~-planar or -anticlinal (-ac)['l,and in the latter case they are "cis" (cis-planar
or -syn-periplanar (-sp) [*l).
The position of 0 5 ' relative to the arabinose is given by the
dihedral angles 05'-C5'-C4'-01'
and 05r-C5'-C4'-C3'19]
which are ca. -55" and 62" respectively in the present case.
The atom 0 5 ' thus lies above the sugar residue, a position that
is preferred in ribonucleosides.
Received: December 14, 1970 [Z 341 IE]
German version: Angew. Chem. 83, 174 (1971)
[*] Dr. W. Saenger and Dr. V. Jacobi
Max-Planck-Institut fur experimentelle Medizin,
Abteilung Chemie
34, Gottingen, Hermann-Rein-Strasse 3 (Germany)
[l] a) A . G. Lezius and K. H. Scheit, Europ. J. Biochem. 3,85 (1967);
b) K. H. Scheif, to be published; c) J. Sirnuth, K. H. Scheit, and E. M .
Gottschalk, Biochim. Biophys. Acta 204, 371 (1970).
[2] P. Roy - Burman: Recent Results in Cancer Research -Analogues
of Nucleic Acid Components. Springer, Berlin 1970.
[ 3 ] W. Saenger and K. H. Scheit, Angew. Chem. 81, 121 (1969);
Angew. Chem.internat. Edit. 8,139 (1969); J.Mol. Biol. 50,153 (1970).
[ 4 ] J. Donohue and K. N. Trueblood, J. Mol. Biol. 2, 363 (1960).
[5] W. Saenger and D. Suck, Acta Crystallogr., in press.
[6] P. Faerber, W. Saenger, K . H. Scheit, and D. Suck, FEBS-Lett. lo,
41 (1970).
6&2
M
Previous investigations['] on this topic led to the isolation of
substituted butadiene-Fe(C0)3 complexes (5). An intermediate
(4) was mentioned. System (4) proves to be stable if C5 is the
bridgehead C atom of a polycyclic system as in complex (2). The
halflife of (2) on thermal decomposition at 135°C in n-octane
is about 20 h. Complex (2),m.p. 133-134OC, isthemajorproduct of the reaction between bullvalene (1) and Fe2(C0)9["], in
which six isomeric complexes of composition C10H,#e2(C0)6
and a complex C,H&,(CO)6
are also formed as minor products.
Fig. 1. The enantiomers of compound (2).
Since (1) contains both an unconjugated diene unit and a vinylcyclopropane group in a position favorable for complex formation, it can form both 1,4-diene complexes and vinylcyclopropane complexes, depending upon the metal system used.
Thus the l,4-diene partial structure bonds to Mo(CO), or
W(CO), groups, leaving the cyclopropane ring intact[I21,while
cleavage of the cyclopropane ring occurs on bonding to metal
systems such as Fe(CO), that are richer in electrons.
Perturbation calculations on a simple Hiickel model of butadiene show that an increase in the distance C4-C6 in (4) leads
to a decrease in the energy of the antibonding orbitals, and an
increase in energy of the bonding orbitals. This would indicate
more extensive back donation from metal to ligand in (2) than
in butadiene-Fe(CO), (6). This effect can be detected experimentally by an increase in the vco frequency in the IR
spectrum of (2) compared to that of (6):
vco in cm-' (hexane as solvent)
[7] W. Saenger and D. Suck,Nature 227, 1046 (1970).
[S] W. Klyne and W. Prefog, Experientia 16, 521 (1960)
[9] E. Shefferand K. N. Trueblood, Acta Crystallogr. 18, 1067 (1965).
(6): 2054, 1989, 1979
(2): (a) 2054, 1996, 1992;
(b) 2024, 1980, 1964.
a = 2,3,4,6-fetrahapto-Fe(CO),
b = 7,8,9,10 - tetrahapto-Fe( CO),
Complex Bonding of a Vinylcyclopropane Group
of Bullvalene to a Transition Metal Vis a n-Ally1
and a o Component'l'
The CH skeleton of (2) was determined by 'H-NMR analysis,
including double resonance and ticklin experiments, on the
basis of the observed coupling pattern6'1. Since the relative
positions of the resonance signals are strongly dependent upon
the solvent the measurements were carried out both in CS, and
in C6H6 solutions.
By Rudolf Aumannrl
Reaction of cyclopropane with H2PtC16 yields a brown complex['] containing a C,Pt rir~g[~l.
Analogous ring systems incorporating rhodium are also knownl41. Vinylcyclopropane
188
The rotons H2,H3,H4 form an ally1 system whose chemical
shift3l4]H2 = 5.15 T, H3 = H4 = 5.4 t[I5l correspond to those
found in similar comp1exes[l6]. H 2 is strongly coupled to H'
= 6.13~(J,,~.=
8.5 Hz), andH3I4t o H 5 =7.13 i. H9910= 6 . 9 5 ~
Angew. Chem. internat. Edit. / Vol. 10 (1971) / N o . 3
and H', H 5 give an AA'CX system ( J s , ~= 7.2 Hz; J~,Jo
=
4.8 Hz; J5,10
= J1,9
= - 1.2 Hz; J1,, = 2.4 Hz)~'~].
The measured coupling constants J6,7 = J7,8 = J1,g= 7.5 Hz (H7 = 6.68 Z,
H8 = 6.29 T) are in good agreement with the values expected.
J, = 11.5 Hz indicates a small dihedral angle between Hs and
H6 and thus also a close proximity of C6 and the allyl system.
As expected, H6 = 8.58 T is strongly shielded by the metal.
A Stable Bis(tricarbony1iron) Complex of Tetracyclo[4.4.0.05~7.0z~10]deca-3,8-diene and Its Dynamic Behavior in Solution[']
Tetracyclo[4.4.0.05*7.0z~
1°]deca-3,8-diene (1) has been postulated by Schrzider as an intermediate in the thermally induced
conversion of bullvalene (2) into naphthalene['], and has recently been enriched to 40-5070 in the photostationary mixture of
hydrocarbons formed on low-temperature photolysis of (2)[3,41.
r
1
IIJ1JaZI
Fig. 2. 'H-NMR spectrum of (2) in CS, solution; 100 MHz; CH2C12
= 4.70 T as internal standard.
The enantiomers of the racemate formed on synthesis of (2)
are configurationally stable on the NMR time scale.
The present communication reports on a stable iron complex
(3) derived from (1) by corn lex bonding of the two vinylcyclopropane partial structures$]. Complex (3), m. p. 172"C, is
formed in the thermal reaction of (2) with Fe,(C0)9 along with
six isomeric compounds of composition C10HloFe2(C0)6and
a compound C4H4Fe,(C0)6[1].
Received: December 18, 1970 [ Z 343a IE]
German version: Angew. Chem. 83, 175 (1971)
[*] Dr. R. Aumann
Organisch-chemisches Institut der Universitat
44 Miinster, Orleans-Ring 23 (Germany)
[ l ] Transition metal complexes of (CH), compounds, Part 2 . This work
was supported by the Deutsche Forschungsgemeinschaft. I am grateful
to Dr. D. Wendisch, Ing. Abt. AP 10, E 41, Bayer-Leverkusen. for
measuring NMR spectra at 220 MHz, and to BASF, Ludwigshafen, for
the supply of cyclooctatetraene. - Part 1: R. Aumann, Angew. Chem.
82, 810 (1970); Angew. Chem. internat. Edit. 9, 800 (1970).
[2] C. F. H. Tipper, J. Chem. SOC.1955, 2045; D. M. Adam, J. Chart,
R. G. Guy, and N. Sheppard, Proc. Chem. SOC.(London) 1960, 179;
J. Chem. SOC.1961, 738.
[3] S. E. Binns, R. H. Cragg, R. D. Gillard, B. T Heaton, and M. F.
Pilbrow, J. Chem. SOC. A 1969, 1227.
[4] D. M. Roundhill, D. N. Lawson, and G. Wilkinson, J. Chem. SOC.
A 1968, 845; H. C. Volger, H. Hogeveen, and M. M. P. Gasbeek, J.
Amer. Chem. SOC.91, 218, 2137 (1969); L. Cassar, P. E. Eaton, and
J. Halpern, ibid. 92, 3515 (1970); T. 3. Katzand S. A . Cerefice, ibid.
91, 2405, 6519 (1969).
[ 5 ] A. D. Ketleyand J. A. Braatz, J. Organometal. Chem. 9, P 5 (1967);
Chem. Commun. 1968, 169; T Shono, T Yoshimura, Y. Matsumura,
and R. Oda, J. Org. Chem. 33,876 (1968); R. G. Milierand P. A. Pinke,
3. Amer. Chem. SOC.90, 4500 (1968).
[6] R. Noyori and H. Takaya, Chem. Commun. 1969, 525.
B
A
Fig. 1. The enantiomers A and B of compound (3)
The C H skeleton of (3) was analyzed by 'H-NMR employing
double resonance and the usual calculations. Mossbauer measurements showed both iron atoms to have the same s-electron
density at the nucleus (IS = 0.215 i 0.003 mm/s) and the
same field gradients (QS = 0.761 i 0.003 mm/s)161, thusestablishing the identity of the chemical environments of both iron
atoms.
As a result of the C,, symmetry of the molecule, the NMR
parameters of (3) show a painvise equivalence: H4 = H8 =
5.29, H 2 = H6 = 5.18, H3 = H7 = 5.66, H' = H5 = 7.04,
H9 = HIo = 8.08 d71. H atoms 2,3,4 and 6,7,8 appear as a
somewhat distorted allyl system in the 'H-NMR spectrum
recorded at 0°C. Coupling constants J2,3 = J6,7 = 8.0, J3.4=
J7,* = 7.0, J1,,= J5,6 = 7.0, and J4,5
= Ji,8= 8.0 Hz, and the
chemical shifts of the allyl protons in the NMR spectrum agree
with the values found for similar iron c ~ m p l e x e s [ ' ~ The
~].
[7] W. J. Irwinand F. J. McQuillin, Tetrahedron Lett. 1968,1937; J. A.
Rotb, J. Amer. Chem. SOC.92, 6658 (1970).
[8] S. Sarel, R. Ben-Shoshan, and B. Kirson, J. Amer. Chem. SOC.87
2517 (1965); R. Ben-Shoshan and S. Sarel, Chem. Commun. 1969,
882.
I91 C. H. DePuy, V. M. Kobal, and D. H. Gibson, J. Organometal.
Chem. 13, 266 (1968).
[ l o ] M. I . Bruce, M. 2. Iqbal, and E G. A . Stone, J. Organometal.
Chem. 20, 161 (1969).
[ l l ] Cf. G.N. Schrauzer, P. Glockner, K. I. G. Reid. and I. C. Paul, J.
Amer. Chem. SOC.92,4479 (1970). The authors isolated bicyclo[4.2.2]de~a-2,4,7,9-tetraene-[Fe(CO)~],as the sole product of this reaction.
In our investigation this compound represented only about 20% of the
product mixture.
[12] Cf. ref. [l].
[13] X-ray structure analysis is currently being performed by Dr. G.
Huttner, Miinchen.
[14] 5% solution in CS,; 100 MHz; CH,Cl, = 4.70 1.
[15] Estimated from the spectrum.
[16] R. Aumann, unpublished.
[ 171 Coupling constants calculated.
Angew. Chem. internat. Edit. / Vol. 10 (1971) / N o . 3
tZ3LGZ
518 529 566
70L
808 t
Fig. 2. 'H-NMR spectrum of (3) at various temperatures (saturated solution in [D,]methylene chloride; 100 MHz).
189
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ally, bonding, complex, bullvalene, metali, group, components, transitional, via, vinylcyclopropanes
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