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chemical-shift of H9.Io can readily be explained for the given
skeleton by assuming a coordination of C9 and C'O to the metal,
thus leading inevitably to the structure shown in Fig. 1.
The AA'XX' system formed by protons 9,lO and 1,5 was
analyzed by computer. The strong vicinal coupling .TI,? = Js,
= 10 Hz indicates a small dihedral angle between H and H .
Consideration of models clearly shows that this si nifies spatial
proximity of C9 and C233,4and of C" and C6x7,' 1' .
The 'H-NMR spectrum of (3) recorded at 0°C is a limiting
spectrum since further lowering of the temperature causes no
change in the shape of the signals. On warming, however,
increasingly rapid exchange of the magnetic environments of
H2+H4 and H6+H8 becomes evident from signal broadening.
Above = 45 "C these resonance signals are averaged (Fig. 2)"OI.
This effect is tentatively interpseted as mutual interconversion
of the enantiomers A and B (Fig. 1).Of all conceivable exchange
processes, this would involve the minimum possible change in
the relative spatial positions of all the atoms involved. Racemization entails inversion at C9 and C'O (Fig. 1). The free energy
of activation AG* measured at the coalescence temperature
in methylene chloride is 15.9 t 0.5 kcal/m~le[~I.
A value of
AG* = 16 kcal/mole was obtained for a similar racemization
of a C,,H,, skeleton attached to a Fe,(C0)6 group[51.
The CH skeleton of (4), like that of the complex (3), was determined from the 'H-NMR spectrum. The coupling constants
52,3= J4,5 = 8.0, J3,4= 5.0 Hz calculated from the AA'XX'
system of the protons 2,3,4,5 agree with the values expected
= 8.0 Hz161. The arithfor such a structure, as do Jl.2=
metic mean H = 5.59 sof the chemical~hifts[~]
of H3a4= 4.80 T
and H2,5 = 6.38 s corresponds to the arithmetic mean of the
chemical shifts of the ally1 protons H6*',' = 5 5 TI']. As expected,
H9 = 9.19 T is strongly shielded by the metal. Thechemical shift
of the bridgehead protons H'*'' = 7.19 T do not differ appreciably from the value observed in the case of (3)C41.
Confirmatory evidence for structure (4) comes from the longrange coupling of H6 and H8 to H' (J6,9 = & = 1.4 Hz)
and the absence of any such coupling of H2 and H5 to H'
in the 'H-NMR spectrum, as well As from the mass spectrum
and elemental analysis.
Received: December 3, 1970;
revised: December 18, 1970 [ Z 343 b IE]
German version: Angew. Chem. 83, 176 (1971)
Dr. R. Aumann
Organisch-chemisches Institut der Universitat
44 Miinster, Orleans-Ring 23 (Germany)
[ I ] Transition metal complexes of (CH),, compounds, Part 3. This work
was supported by the Deutsche Forschungsgemeinschaft.I am also grateful to BASF, Ludwigshafen, for the supply of cyclooctatetraene. - Part
2: R.Aumann, Angew. Chem. 83, 175 (1971); Angew. Chem. internat.
Edit. 10, 188 (1971).
[2] G. Schroder, Chem. Ber. 97, 3140 (1964).
[3] K . Hojo, R. T. Seidner, and S. Masamune, J. Amer. Chem. SOC.
92, 6641 (1970).
Jones, If., S. D. Reich, and L. T. Scott, J. Amer. Chem. SOC.92,
3118 (1970).
[ 5 ] R. Aumann, unpublished
[61 The Mossbauer spectrum was kindly recorded by Dr. B.Hentschel,
[7] Saturate&solution of (3) in [D2]methylene chloride; 100 MHz; reference signal CH2C12 = 4.70 T.
[8] An X-ray structure analysis is currently being performed by Dr. 1. C.
Paul, Urbana, Ill.
[9] The calculation of errors is based on the assumption of an inaccuracy
in the determination of the coalescence temperature of 33 ? 5°C.
[lo] An accidental overlap of signals due to the temperature shift was
excluded by careful calibration of the temperature dependence of the
chemical shifts.
By Rudolf Aumann[*l
Isobullvalene (1) has recently been synthesized by Masamune
e f aL[2] and Katz et al.C31. This communication reports on a
metal complex (4) derived from ( 1 ) by complex bonding of the
conjugated diene- and vinylcyclopropane units141 to Fe(C0)3
(4), m.p. 123"C, is formed quantitatively at 12O"Cin the thermally induced skeletal rearrangement of a Fe,(CO complex
(3) of tetracycI0[]deca-3,8-diene
(2) .
4 80
5 63
6 38
919 r
Fig. 'H-NMR spectrum of (4). Solution in CHC13; T M S as internal
standard; 100 MHz.
Isomerization of (3) to (4) proceeds by way of a 1,2-rearrangement of the carbon skeleton, in which one of the two sevenmembered rings is transformed into a six-membered ring that
is coordinated to a Fe(C0)3 group via the n-ally1 system C6,7,8
and a two-center bond (from C'). No further 1,2-rearrangement
to give a bond between C2 and C9, thus affording the known
compound 9,lO-dihydr0naphthalene-[Fe(CO)~], (5)191, was
[*] Dr. R. Aumann
Organisch-chemisches Institut der Universitat
44 Miinster, Orleans-Ring 23 (Germany)
111 Transition metal complexes of (CH),, compounds. Part 4. This work
was supported by the Deutsche Forschungsgemeinschaft. I am also
grateful to BASF, Ludwigshafen, for the supply of cyclooctatetraene. Part 3: R. Aumann, Angew. Chem. 83, 176 (1971); Angew. Chem.
internat. Edit. 10, 189 (1971).
[2] K. Hojo, R. T. Seidner, and S. Masamune, J. Amer. Chem. SOC.92,
6641 (1970).
[3] T. J. Karz, J. J. Cheung, and N. Acron, J. Amer. Chem. SOC.92,
6643 (1970).
141 R. Aumann, Angew. Chem. 83,175 (1971); Angew. Chem. internat.
Edit. 10, 188 (1971).
[5] Cf. ref. [I].
[6] R. Aumann, unpublished results.
(71 109" solution in chloroform; TMS as internal standard.
[8] Estimated from the spectrum.
[9] Cf. G. N. Schrauzer, P. Glockner, K. I. G. Reid, and I. C. Paul, J .
Amer. Chem. SOC.92, 4480 (1970).
Angew. Chem. internat. Edit. / Vol. 10 (1971) / N o . 3
found t o occur o n heating of (4) to 180°C. It is therefore clear
that complex ( 4 ) cannot be a n intermediate of the thermally
induced (180°C) isomerization of bicyclo[4.2.2]deca-2,4,7,9tetraene-[Fe(C0)3]2[9] to (5).
Received: December 3, 1970,
revised December 18, 1970 [ Z 343 c IE]
German version Angew. Chem. 83, 177 (1971)
The transformation (4)3(5)+(3) is also important for the synthesis of (Z), a key compound in the stereochemistry of ferrocene derivatives. To our knowledge, (2) is the only known ferrocene derivative whose racemate gives both antipodes in good
yield, and which can b e transformed with a high degree of stereoselectivity into ferrocene derivatives with a plane of chirality.
T h e substitution of the acetate by a dimethylamino group
proceeds in excellent yield and provides for the synthesis of
(2) from (4) by an alternative to the phosgene method161.
The Retentive Nucleophilic Substitution of (R)a-Ferrocenylethyl Acetate
By George W. Gokel and Ivar K. Ugi[*]
It is well known that reactions of esters with nucleophiles
proceed via an additive attack of the nucleophile on the ester
carbonyl followed by elimination of the alkoxide moiety['],
leading t o cleavage of t h e acyl-alkoxy bond. Recently, Richards
et aL['l demonstrated that ethanolysis of a-ferrocenylethyl acetate afforded 1-ethoxy-1-ferrocenylethaneand acetic acid. This
result indicates that the reaction proceeds by a mechanism other
than that already known.
O u r interest in the a-ferrocenylethyl system arises from its potential as a model system of optically active amine components
for stereoselective four component syntheses of peptides13!
This synthesis necessitates cleavage of the auxiliary group
introduced by the amine component from t h e four component
condensation product such that the chiral amine can be regenerated in its original configuration. T h e stereochemical
integrity of the a-ferrocenylethylcarbonium i ~ n [ ~ I p r o m p t ethe
investigation reported here
Since a-ferrocenylethyl compounds (1) with a strong leaving
group, for example, X = CI['], have a pronounced tendency
to eliminate H X leaving vinyl ferrocene, we attempted to find
a suitable group, X, such that the transformation
(I), X
OH -+ ( I ) , X
proceeds in good yield and is easy t o carry out. W e found that
the reaction cycle A + D proceeds in good chemical yield at all
stages and with complete configurational retention throughout
the cycle.
D Fc-CH(NMe,)-CH,
Fc = CioHpFe-;E: Acetyl chloride, aluminum chloride in dichloromethane for 2 hours at 0°C 191, yield = 95%; F: Sodium bismethoxyethoxy
aluminate [lo] in benzene (1 M) for 1 hour, yield = 90%, G: boil with
5 equiv. acetic acid in benzene for 3 hours, yield = 96%
The replacement of t h e acetoxy group in (5) by ammonia
proceeds in only 45% yield.
Pertinent experiments with other easily prepared esters of
a-ferrocenylethanol a r e in progress.
Received: December 23, 1970 [Z 337 IE]
German version: Angew. Chem. 83, 178 (1971)
G. Gokel and Prof. Dr. I. Ugi
Department of Chemistry
University of Southern California
University Park, Los Angeles, Cal. 90007 (USA).
[I] M. L. Bender, Chem. Rev. 60, 53 (1960).
[2] J. H. Richardsand E. A . Hill,J. Amer. Chem. SOC.81,3484 (1959);
E. A. Hilland J. H. Richards, ibid. 83, 3840 (1961); 83, 4216 (1961).
[3] I. Ugi, Rec. Chem. Progr. 30,289 (1969); G. Gokel, P. Hoffmann,
H. Kleimann, H. Klusacek, G. Ludke, D. Marquarding, and I. Ugi, in
I. Ugi, Isonitrile Chemistry. Academic Press, New York 1971, Chap. 9.
[4] G. Gokel, P. Hoffmann, H. Klusacek, D. Marquarding, E. Ruch,
and I. Ugi, Angew. Chem. 82,77 (1970); Angew. Chem. internat. Edit.
9, 64 (1970).
[5] R . A . Benkeserand W.P.Fitzgerald,J.Org.Chem.26,4179(1961).
[6] D. Marquarding, P. Hoffmann, H. Klusacek, G. Gokel, and I. Ugi,
J . Amer. Chem. SOC.92, 5389 (1970).
[7] M. J. Nugenf, R . E. Carter, and 1. H. Richards, J. Amer. Chem. SOC.
91, 6145 (1969).
[8] E S. Arimoto and A . C. Haven, J. Amer. Chem. SOC.77, 6295
[9] Several methods for the preparation of acetyl ferrocene in yields of
50-90% have been reported: M. Rosenblum and R. B. Woodward,
J. Amer. Chem. SOC.80, 5443 (1958), describe the preparation of (7)
with aluminum chloride and acetyl chloride in unspecified yield. See
also, M. Dub: Organometallic Compounds, Springer, New York 1966,
Vol. l., p. 285.
[lo] M. Capka, V. Chvalovsky, K. Kochloefl, and M. Kraus, Coll.
Czech. Chem. Comm. 34, 118 (1969); Aldrich Chemical Co., Red-AI
product bulletin, no. 15, 109-2.
Cycloadditions of Phosphonodithioic Anhydrides;
Formation of Dienephosphinodithioic Acids
By Alfred Ecker, Immo Boie, and UIrich Schmidt[']
(2): Preparation and resolution [6]: [a]::= + 14.1"C ( c = 1.5, ethanol);
after reaction cycle: [a]? = + 14.0" ( c = 2.3, ethanol).
(3): [a]';' = +40.8" (c = 1.2, methyl cellosolve) [5].
= -28.9" (c = 1.7, benzene).
(5): [aILi4= -27.1" (c = 1.4, ethanol).
A: Ref. [91;B: Stirin1:l aqueousacetonitrileat ca.2O0Cforl5 hours[7]
yield = 90%; C: Ref. [S]; D: Stir at ca. 20°C with five equivalents of
dimethylamine for 15-20 hours in aqueous methanol, yield = 84%.
Angew. Chem. internat. Edit. / Vol. 10 (1971) / N o . 3
In connection with o u r studies of the photochemical reaction
between cyclophosphines and dienes['.'I we have treated the
reaction product with sulfur in order t o characterize t h e resulting
( 1 ) as stable disulfides (2). I n
so doing we found that unreacted cyclophosphine (3) forms a
phosphonodithioic anhydride (4) that adds t o a n excess of diene
to give the six-membered heterocyclic compound (5) in a reaction that proved to b e almost universally applicable. To carry
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