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Cycloadditions of Phosphonodithioic Anhydrides; Formation of Dienephosphinodithioic Acids.

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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
d
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
Fe
0
(1)
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
=
NH,
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.
1
0
0
(5)
Fc-H
Fc-CO-CH3
(6)
(7)
-%
A
Fc-CH(0H)-CH3
(4)
Fc-CH(0Ac)-CH3
(5)
D Fc-CH(NMe,)-CH,
(2)
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)
[*I
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
(1955).
[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[']
(4)
(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].
(4):[a];;
= -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
3,6-dihydro-1,2-diphosphorins
( 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
191
out the addition, the dithioic anhydride (which is usually readily
accessible from phosphonothioic dichloride and W2S[31) is
heated for several hours with an excess of the diene in an
autoclave at about 100°C.
The structures of the adducts were deduced from their NMR
spectra. (Sf) in CCl,: multiplet at 6 1.89 (3H), doublets (J =
13 Hz) at 6 1.99 (3H) and 2.80 (ZH), a doublet with fine
structure at 6 3.54 (2H), and a multiplet at 6 5.86 (1H). The
absence of y-coupling with the phosphorus indicates that the
methyl group is in position 5. Coupling of this kind is observed
for 4-methyl groups, e.g. in (5c) and (Sj).
Cleavage of (53) with NaH and esterification of the butadienephosphinodithioic acid (6j):
Compound (5;) (5.2 g) and NaH (0.5 g) are stirred for 2 h at
75°C in anhydrous 1,2-dimethoxyethane (60 ml). p-Nitrobenzyl bromide (4 g) in ether (50 ml) is then added to the
reaction mixture and the resulting NaBr is filtered off immediately. The solution is evaporated down to a volume of 20 ml
and the product filtered off with suction after standing for
several days. Recrystallization from ether furnishes 3.8 g of
p-nitrobenzyl-P- (2,3 -dimethylbutadienyl) -P- (2 - thieny1)phosphinodithioate (7j).
Received: February 16, 1970 12 336 IE]
Germanversion: Angew. Chem. 83,178 (1971)
Publication delayed at authors' request
On reaction with strong bases in aprotic solvents (e.g. NaH in
diglyme) initial metalation is followed by ring cleavage to give
the dienephosphinodithioic acids (6) which react in sifu with
alkyl halides to give the esters (7).
ESR Investigations of an Oscillating Redox
System'"*I
By Horst Friihbeis and Alberf Hoder"]
ii
-1."
Periodic processes play an important role in biological systems"]. In addition to oscillating enzymatic systemsf2],several
purely chemical systems have been described which oscillate
in an homogeneous
One of these - the oxidation
of malic acid by bromate in acid medium, which is catalyzed
by Mn2+ ions and occurs in a limited concentration range as an
- was chosen by us as a model reoscillating redox
action on the following grounds:
(5)
(5)
R
R'
R2
Yield(%)
1. Despite the unphysiological pH range (see below) and oxidation pool (bromate) two important biochemicals are involved
(malic acid and Mn2+).
R2
R'
M.p ("C) B p. ("C/
tom)
I
Methyl
Isopropyl
Thienyl
Thienyl
65
88
90
75
76
76
86
70
70
33
62
51
61
60
2. In ESR spectroscopy we had a "probe" at hand for specific
measurement of the concentration of the Mn2+catalyst. Its characteristic six-line spectrum is not influenced under the conditions of the oscillating mixture, either by malic acid and bromate concentration or by the concentration of H + ions.
3. We found (Fig. 1) that the catalyst participates in the oscillation.
10710.01
10110.015
160/0.001
13510.4
14410.4
1-
Synthesis of (5j):
Thiophene-2-phosphonodithioic anhydrideC4] (30 g) and 2,3dimethylbutadiene (50 ml) are heated together for 2 h at 100°C
in an autoclave. The product crystallizes on cooling of the reaction mixture. Recrystallization from ethyl acetate affords
colorless crystals (36 g) having m.p. 85°C.
[*] Dr. A. Ecker, Dr. I. Boie, and Prof. Dr. Ulrich Schmidt
Organisch-Chemisches Institut der Universitat
A-1090 Wien, Wahringerstrasse 38 (Austria)
111 U. Schmidt, I. Boie, Ch. Osterrohf,R. Schroer, and H. E Grdtzmacher, Chem. Ber. 101, 1381 (1968).
[2] U. Schmidt and I. Boie, Angew. Chem. 78, 1061 (1966); Angew.
Chem. internat. Edit. 5, 1038 (1966).
[3] P. E. Newallis, J. P. Chupp, and L. C. D. Groenweghe,J. Org. Chem.
27, 3829 (1962); R. Kolln and G. Schrader, German Pat. 1099535
(1961).
[4) H. Hirai and H. Yoshioka,Deutsche Offenlegungsschrift 1806 105
(May 22, 1969), Sumitomo Chemical Co. Ltd., Osaka; Chem. Abstr.
71, 50213h (1969).
192
123101/
ai
bl
Fig. 1. Calculation of the osciIlating portion of the Mn2+ ions ( b =
loo%, 2a = 25 %). a) Derivation of the intensity of the ESR absorption
line as a function of the magnetic field, b) concentration of Mn2+ as
a function of time (magnetic field constant). Mixture: 20ml lo-'^
MnS0, in ZN H'SO,, 50ml 2~ H2S04, 40ml I Mmalic acid and 40ml
0 . 2 5 ~aqueous KBr03 solution (see arrow). Varian x band spectrometer, Mod. 125, Amp. 1000, Ho 3155 gauss, rate of pen recorder
12.4 cmlmin.
Measurements were carried out at the maximum (or minimum)
of one of the six absorption lines of Mn2+ (Fig. 1a) at constant
field; the Mn2+ concentration was recorded as a function of
time (Fig. 1b). The reaction mixture was mixed outside the cuvet
through which it was subsequently pumped by means of an allteflon pump.
With this arrangement we were able to record the initial phase
of the oscillation (Fig. 1b). It can be seen from the same figure
that maximally about 25% of the Mn" ions occur in a higher
oxidation state at the concentrations of the redox pool quoted.
The length of the period t is influenced by various reaction mixture parameters, the hydrogen ion concentration playing a significant role. The period is short at high H + ion concentration
and long at low H + ion concentration. Under the experimental
Angew. Chem. internat. Edit. / Vol. 10 (1971) / N o . 3
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