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Isomer Formation in the Cycloaddition Reaction of 2 7-Dimethyl-2 4 6-octatriene with Tetracyanoethylene.

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[7] B . Bogdanouic, C. Kriiger. P. Locarelli, Angew. Chem. 91. 745 (1979);
Angew. Chem. Int. Ed. Engl. 18, 684 (1979).
(81 B. Wermeckes, Dissertation, Universitat Bochum 1979.
191 Nachr. Chem. Tech. Lab. 28, 78 (1980), and references cited therein.
[lo] a) D. Y. Curtin. J . W. Crump. J. Am. Chem. SOC.80,1022 (1958); b) N . L.
Allinger. R . B . Hermann, J. Org. Chem. 26. 1040 (1961); c) D. Seyferih,
L. G. Vaughan, J. Am. Chem. SOC.86. 883 (1964); d) G. M. Whitesides.
C. P. Casey. J. K . Krieger. ibid. 93. 1379 (1971); e) J. W . Patterson Jr.. J.
H . Fried. J. Org. Chem. 39, 2506 (1974); f) C. J. Sih, R. G. Salomon. P.
Price. R . Sood, G . Peruzzotli. J. Am. Chem. SOC.97, 857 (1975); g) A. F.
Kluge, K . G. Unlch, J . H . Fried. ibid. 94, 7827 (1972); h) E. J. Corey, D .
J. Beames, ibid. 94. 7210 (1972); i) E. J. Corey. H. S. Sachdeu. ibid. 95,
8483 (1973); j) C. J. Sih, J. 8. Heather, R . Sood. P. Price. G. Peruzzotti.
L. F. Hsu Lee, S. S . Lee. ibid. 97, 865 (1975); k) H . Neumann. D. Seebach. Chem. Ber. I l l , 2785 (1978), and references cited therein.
[ I 11 One route to (E)-I-lithio-I-alkenes which circumvents the (Q-I-halo-Iwith n-butylalkenes is the reaction of (E)-I-tri-n-butylstannyl-I-alkenes
lithium described by E. J . Corey and R . H . Wollenberg (J. Org. Chem.
40, 2265 (1975)).
1121 a) C. Zwe&fe/. C. C. Whitney. J. Am. Chem. SOC.89, 2753 (1967); b) H. C.
Brown. D . H . Bowman, S . Misumi. M . K . Unni, ibid. 89, 4531 (1967); c)
H.C. Brown, T. Hamaoka, N . Rauindran. ibid. 95, 5786 (1973); d) R . B.
Miller, T. Reichenbach, Tetrahedron Lett. 1974, 543.
1131 We wish to thank Frau Chem.-Tech. A. Marjanouit for valuable assistance in organizing the experimental procedures.
1141 3/4 of the vinyllithium present in solution could be isolated in this way;
C2H,Li.C4Hx0 (106.0); calc. 6.55% Li, obs. 6.56% Li; hydrolysis afforded 94% of the calculated amount of ethylene.
[IS] D. Seyferth, L. G. Vaughan, J. Organomet. Chem. I, 138 (1963).
[I61 Ca. 70% of (2) present in the solution could be isolated; C2HSLi.C,H80
(120.1); calc. 5.76% Li; obs. 5.75% Li.
Isomer Formation in the Cycloaddition Reaction of
2,7-Dimethyl-2,4,6-octatriene with
By Alden D.Josey[''
Dimerization of isoprene in the presence of maleic anhydride bis(triphenylphosphane)palladium(o) occurs in a
linear, tail-to-tail fashion to give 2,7-dimethyl-1,3,7-octatriene, which under conditions of base-catalysis rearranges
to 2,7-dimethyl-Z,trans-4,6-octatriene
(la)"'. Isoprene is dimerized directly to ( l a ) by dad-modified chromium catalysts (dad = 1,4-diaza-1,3-diene)[2! Reaction of ( l a ) with tetracyanoethylene (TCNE) resulted in formation of the "expected" Diels-Alder adduct 3,3-dimethyl-6-(2-methyl-lpropenyl)-4-cyclohexene-l,1,2,2-tetracarbonitrile (4a)[z1.
The behavior of the triene in cycloaddition reactions
proved, however, to be somewhat different: (la) reacts
with T C N E to form two cycloadducts in amounts dependent on the polarity of the solvent.
In anhydrous solvents, equimolar amounts of ( l a ) and
T C N E produce an intense blue charge-transfer complex
whose color is discharged slowly, increases in intensity as
solvent is evaporated, and disappears completely o n removal of the solvent in uacuoP1.The crystalline residue
could be separated by extraction with hot hexane into two
isomeric compounds-the less-soluble (3a), m. p. = 140141.5 "C (from ethanol), and (4a), m.p. =90--92"C. Conversion was quantitative.
The isomers were identified by NMR and UV spectroscopyIa1.As indicated by the relative intensities of the 'HNMR signals at 6=3.55 (d, J = 10 Hz) and 4.15 (d, J = 10
Hz) of the non-olefinic ring H atoms of the [2 21-cycloadduct (3a) or of the normal [2+4]-cycloadduct (4a) in the
product mixture, formation of (3a) is favored by more polar solvents [(3a):(4a)= 33 :67 in tetrahydrofuran (THF),
[*I Dr. A. D. Josey
Experimental Station, E. I. du Pont de Nemours and Co.
Wilmington, Delaware 19898 (USA)
0 Verlag Chemie GmbH. 6940 Weinheim. 1981
SO : S O in acetonitrile], implicating (2) as a key intermediate.
(30). R
R' = CH3
(la), R
(Ih), R
T C N E . 7 >
R' CH3
H, R'= CH3
That the cycloaddition of TCNE and substituted 1,3-butadienes leads to competing [2 21-42 + 41-cycloadditions
is well known e . g . the reaction of (5a) to (6a)-in which
the cyclobutane ring is closed at the less-hindered diene
terminus-and to (7a) [0% in nitromethane, 30% in cyclohexane]. Our own work shows that full methyl-substitution
of both diene termini in (Sb) does not hinder the reaction
but directs its course in CH,CN exclusively to the [2+2]adduct (66) in quantitative yieldf6'.
(Sh), R
= CH3
(6a), R
16h), R
= H
= CH,
(7tr), R
In the formation of (3a) electronic factors (hexadienyl
cation in (2)) alone cannot account for the regiospecificity
of the 12 21-cycloaddition toward the more hindered terminal double bond since the reaction of the less substituted triene (Ib) with T C N E results in exclusive formation
of the [2 41-adduct (4b)[').
It appears that the ability of the diene portion of the
polyene to assume a planar, or very nearly planar, cisoid
configuration in the transition state for cycloaddition
(good in (Ib), poor in (5b), intermediate in ( l a ) )must share
with electronic stabilization of intermediate ions the role
of determining how cycloaddition products are partitioned
into the two observed modes. The unusual triene ( l a ) represents a case in which these effects are sufficiently balanced to permit both reaction modes.
Received: February 25, 1980 [Z 795 I€]
German version: Angew. Chem. 93, 702 (1981)
[I] A . D.Josey. J. Org. Chem. 39, 139 (1974).
121 H. tom Dieck. A. Kinzel, Angew. Chem. 91. 344 (1979); Angew. Chem.
Int. Ed. Engl. 18. 324 (1979).
[3] 6.8 g (la) and 6.4 g TCNE (0.05 mol of each) in 75 m L THF or CH,CN;
the initially intense blue solution becomes pale green after 4 d at 25 "C
under N2.
[4] 'H-NMR (CDCI,. TMS int.): (3a) S = 1.48 (s, 3H). 1.53 (s, 3 H), 1.82 (s,
6H),3.55(d, IOHz, lH),5.3-6.9(m,3H);(4aJ6=1.67(s,3H),1.78(s,
3 H), 2.0 (m,6 H), 4.15 (d, 10 Hz, 1 H), 5.35 (d, 10 H I , 1 H), 5.4-5.95 (m,
2H, AB-system, 10 Hz; low- and high-field components exist as doublets
with J=2.0 or 1.5 H z splittings). UV (CH2C12): (3a) 1 = 2 6 3 nm
( E = 25 400).
0570-0833/81/0808-0686 $02.50/0
Angew. Chem. Ini. Ed. Engl. 20 (/98/)
[S] C. A. Stewart. J. Org. Chem. 28, 3320 (1963); J. Am. Chem. SOC.84, 117
161 (66). m.p.= 128.5-1295°C (from ethanol); ‘H-NMR (CDCI,, TMS
(d, 1 Hz, 3H), 1.51 (s, 3H), 1.49(s,3H).
[7] Reaction in THF; {4b), m.p.= 104--104.5”C (from hexane/CH2C12); ‘HNMR (CDCI,, TMS int.): 6=5.75 (s, 2H), 5.33 (d, 10 Hz, 1 H), 3.99 (d, 10
Hz, I H), 3.24 (q, 7 Hz, 1 H), 1.88 (s, 6H), 1.61 (d, 7 Hz, 3 H).
complex the distance betwee? the two metal ion sheets
only increases by 0.9 to 17.9 A. The tacticity of the product, small structural changes, as well as the control of the
reactivity by the ionic nature of the matrix, make a topochemical control of the reaction probable. From Figure 1 it
is evident that the polymer chains, formed by IP-addition
of the diene groups, lie extended in a plane parallel to the
inorganic matrix.
Synthesis of a Novel Amphoteric Polyelectrolyte
by Polymerization of 6-Amino-2,4-hexadienoic Acid
in Layer Perovskites[”’
N” 3
By Bernd Tieke and Gerhard Wegneri*l
Alkylammonium compounds can be incorporated into
inorganic matrices via hydrogen bridges. Well known examples of this phenomenon are intercalations in sheet silicates”] and formation of complex crystals with transition
metal halides MX2, the so-called layer perovskites of formula (C,H,, + I-NH3)2MX4[21. Numerous investigations
of the magnetic properties and phase changes in these
layer perovskites have appearedf3]. However, their suitability as matrices for organic solid state reactions has not yet
been studied.
The starting point for our investigations was the observation that o-amino acids, as well as n-alkylamines, are
able to crystallize in “layer perovskites”. 6-Amino-2,4hexadienoic acid ( I ) forms complex crystals with several
transition metal halides MX2 (CdCl,, CdBr2, MnCl,,
FeCI2, and CuC12).Only the complexes with CdC12, MnCl,
and FeCl, undergo a solid state reaction, upon UV(A= 254 nm) and 60Co-y-irradiation, to form a 1,4-disubstituted trans-polybutadiene of structure [2).
n C H R ’=C H-CH=C
H R2
The degree of conversion amounts to over 90% after a ydose of 30 Mrad. In the other complexes no polymerization reaction occurs. The possibility of a 1,4-addition polymerization of 1,4-disubstituted trans,trans-dienes has not
previously been demonstrated, either for reactions occurring in the solid state or within canal complexes‘41.Apart
from signals from the unreacted monomer, the 22.6 MHz
I3C-NMR spectrum of a 1 NKOD solution of the dissolved
crystals only showed signals from the 1,4-adduct after 30
Mrad irradiation: COO- (6= 184.2), isolated trans-C=C
(6= 135.4/134.2) and three signals in the aliphatic C atom
region (6= 59.2/49.8/45.2), which are assigned to the two
asymmetric C atoms formed and the CH,NH, group.
Assuming for present that the signals from the asymmetric C atoms can be assigned only to one chiral center and
considering the mode of formation of the polymer in the
crystalline state, an erythro-diisotactic arrangement of the
substituents is proposed. The polymer occurs as a racemate.
X-ray structure investigations indicate that only slight
structural changes occur during the reaction. In the CdC12
[‘I Prof. Dr. G. Wegner [‘I, Dr. B. Tieke
lnstitut fur Makromolekulare Chemie der Universitat
Stefan-Meier-Strasse 3 I, D-7800 Freiburg (Germany)
Fig. 1. Schematic representation of the reaction.
The polymerized amino acid can be separated from the
matrix by solvation in strong bases and finally by reprecipitation as an amphoteric polyelectrolyte. It has an average molecular weight of ca. 35 000 (determined by GPC in
2.5% aqueous N(CH3)40H solution), dissolves in strong
acids (pH 52.0) and bases (pH 2 10.2) and is crystalline
after reprecipitation. At present, we are investigating its
suitability as a polymeric complexing agent.
2 mL of a 0 . 5 aqueous
solution of MX, is added to
(2 mmol) dissolved in ca. 20 mL 0.1 N HCI. Crystallization follows by evaporation of the solvent over P205in a
desiccator. It is recommended that operations with Mn2+
and Fez+ are carried out under a nitrogen atmosphere.
Received: January 14, 1981 [Z 796 IE]
German version: Angew. Chem. 93. 693 (1981)
CAS Registry numbers:
(1). 78249-26-0; (1) homopolymer, 78249-42-0
[I] G. Lugaly, A. Weiss, Kolloid-2. 2. Polym. 243, 48 (1971).
[21 a) U. Walther, D. Brinkmunn. G. Chapuis, H . Arend. Solid State Commun. 27, 901 (1978); b) H. Arend, W. Huber. F. H . Mischgofsky, G . H .
Richfer-uan Leeuwen, J. Cryst. Growth 43, 213 (1978).
[31 a) H. Arend, J. Schoenes, P. Wuchfer,Phys. Status Solidi 869. 105 (1975);
b) W. Deprneier, J. Felsche. G. Wildermufh,J. Solid State Chem. 21, 57
(1977); C) C. BeNifto, P. Day, J. Chem. SOC.Dalton Trans. 1978. 1207.
[41 a) G. M. J. Schmidt et 01.: Solid State Photochemistry, Verlag Chemie,
Weinheim 1976, p. 93pp.; b) K. Takemofo,M. Miyafa, J. Macromol. Sci.
C18. 83 (1980).
[Sl f. Kurrer, R. Schwyzer, Helv. Chim. Acta 29. 1191 (1946).
A General Procedure for Intramolec$ar a-tertAlkylation of Carbonyl Compounds[
By Manfred T. Reetz, Ioannis Chatziiosifidis, and
Konrad SchweIinus[”
The problem of a-tert-alkylation of carbonyl compounds can be solved in a general way by reacting the cor[*I Prof. Dr. M. T. Reetz, Dr. I. Chatziiosifidis and Dipl.-Chem. K. Schwell-
[‘I Author to whom correspondence should be addressed.
[**I This work was supported by the Stiftung Volkswagenwerk (Project:
,,Physik und Chemie unkonventioneller Materialien”). We thank Dr. H .
Arend. ETH Zurich, for stimulating discussions.
Angew. Chem. I n r Ed. Engl. 20 (1981) N o 8
Fachbereich Chemie der Universitat
Hans-Meerwein-Strasse, 3550 Marburg (Germany)
This work was supported by the Fonds der Chemischen Industrie.
0 Verlag Chemie GmbH. 6940 Weinheim. I981
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reaction, cycloadditions, formation, tetracyanoethylene, dimethyl, isomers, octatriene
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