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The Zirconocene-Induced Coupling of Butadiene with Carbonyl Compounds.

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obtained in the reaction of Cl[P(CH3)3]4WCHwith CO in
the presence of aluminum trichloride'".
(1983) 159; Angew. Chem. Int. Ed. Engl. 22 (1983) 149; Angew. Chem.
Suppl. 1983, 148.
I81 F. R. Kreissl, K. Eberl, W. Uedelhoven, Angew. Chem. 90 (1978) 908;
Angew. Chem. Int. Ed. Engl. 17 (1978) 860.
.[9] M. R. Churchill, H. J. Wasserman, S . J. Holmes, R. R. Schrock, Organometallics 1 (1982) 766.
1121 Cf. J. L. Templeton, B. C. Ward, J. Am. Chem. SOC.102 (1980) 3288.
1151 Cf. C. G. Kreiter, K. Nist, H. G. Alt, Chem. Ber. 114 (1981) 1845.
c 6H4C H3
The Zirconocene-Induced Coupling of Butadiene
with Carbonyl Compounds**
By Gerhard Erker*, Klaus Engel, Jerry L. Atwood, and
William E. Hunter
Za, R = CH,
2b, R = CzHs
The products 2a and 2b can be isolated as orange saltlike solids, whereas 2c is a diamagnetic beige molecular
solid; all three compounds are soluble in dichloromethane.
The compositions and structures of the products were determined by elemental analysis and by mass-, IR-, and
NMR-spectroscopy. In each case the K O solution spectrum (CHzCIz) exhibits a very intense band at 1975, 1976,
and 1970 cm-', respectively. The 'H-NMR spectra of the
novel acetylene complexes have the expected number of
signals in the correct intensity ratios. The I3C('H)-NMR
spectrum (CD2CI2,&value rel. CDzC12P 54.2 ppm) of 2b
contains 12 signals: W-CO
223.4 [J(WC)= 135.0,
J(PC)=6.8 Hz]; CECO 228.8 [J(WC)=66.7, J(PC)=6.0
Hz]; C=CO 193.7 [J(WC)=32.5; J(PC)=6.0 Hz]; C.5H4
141.6, 133.4, 130.0, 129.4; C5H5 93.6; OCHz 72.3; P(CH3)3
21.8 [J(PC)=37.6 Hz]; CH3 21.5; CHzCH315.1. The strong
deshielding of the alkyne C atoms in 2 suggests a 4n-electron ligand['21, whereas the relatively large WC coupling
constants indicate high o-bond contribution^['^] between
the central metal atom and the two carbon atoms; a second
limiting structure for the description of the complexes, a
metallacyclopropene system, therefore, cannot be excluded. In each case the 31P['H}-NMRspectra (CDZCI2,6value rel. ext. H3P04)of 2a-2c exhibit a singlet accompanied by tungsten satellites: - 17.2 [J(WP)=394.3 Hz],
- 17.3 [394.3], and - 16.0 r399.81, respectively. In the mass
spectra (FD) of 2a and 2b, the signals of the cations appear at m/z 499 and 513, respectively, in addition to signals at 547 and 561, respectively, whose relative intensities
are markedly dependent on the temperature of the emitter;
this corresponds to CO/P(CH3), exchange in the cations.
Received: February 17, 1983;
revised: April 11, 1983 [ Z 279 IE]
German version: Angew. Chem. 95 (1983) 503
The complete version of this communication appears in:
Angew. Chem. Suppl. 1983. 631-638
Additions of aldehydes and ketones to alkyltitanium
and alkylzirconium compounds are attracting increasing
attention as synthetically useful reactions, often with surprisingly high selectivities. Since X-ray structure analyses"]
have shown (s-cis-diene)zirconocene complexes exhibit
substantial alkylmetal character it was tempting to consider the regioselective coupling of isoprene with aldehydes and ketones at the bis(q-cyc1opentadienyl)zirconium
unit as being a further example of this reaction typer3].
Reaction of the equilibrium mixture of (s-trans- and scis-q4-butadiene)zirconocene 1 + 2 (25 "C: 45/55) with
benzophenone, acetone, cyclododecanone, acetophenone,
pinacolone and isobutyraldehyde (3a-f) leads to the or-
CAS Registry numbers:
1, 61202-59-3; ta, 85748-32-9; Zb, 8573554-2; Zc, 85735-55-3; [Me30][BF4],
420-37-1 ; [Et,O][BF,], 368-39-9.
0 Verlag Chemie GrnbH, 6940 Weinheim, 1983
H ic H,
),cR' R' OH
ganometallic products 4a-f having a oxazirconacycloheptene structure; this was confirmed by X-ray structure
analysis in the case of 4a (Fig. 1). Hydrolysis of 4 affords
mixtures of the alcohols 5 and 6.
Addition of 3 to 2 was expected to give directly the seven-membered metallacycles 4 with cis-configurated double
bond. Surprisingly, however, 4a-f are not formed in this
way. In the equilibrium mixture 1 + 2 the (s-trans-q4-butadiene)zirconocene 1 reacts more rapidly with 3 than its
isomer 2 with 3, even at room temperature. This becomes
impressively confirmed upon reacting the mixture of 1 and
2 (45 : 5 5 ) with benzophenone 3a at low temperatures.
Above - 25 "C slow formation [z,,~(- 20 "C) = 1 h] of 4a is
found to take place. The thermally-induced equilibration
1 + 2 is "frozen in"[z1; reaction of 1 with 3a is the sole
reaction recorded 'H-NMR spectroscopically.
[2] F. R. Kreissl, W. Uedelhoven, K. Eberl, Angew. Chem. 90 (1978) 908;
Angew. Chem. Int. Ed. Engl. 17 (1978) 859.
161 F. R. Kreissl, M. Wolfgruber, W. Sieber, H. G. Alt, Angew. Chem. 95
Priv.-Doz. Dr. G. Erker, K. Engel
Abteilung fur Chemie der Universitat
Postfach 1021 48, D-4630 Bochum 1 (Germany)
Prof. Dr. J. L. Atwood, Dr. W. E. Hunter
Department of Chemistry, University of Alabama
University, Alabama 35486 (USA)
This work was supported by the Minister fur Wissenschaft und Forschung des Landes Nordrhein-Westfalen and by the Fonds der Chemischen Industrie.
0570-0833/83/0606-0494 $02.50/0
Angew. Chem. In[. Ed. Engl. 22 (1983) NO. 6
No thermally-induced reaction is observed at - 50 "C,
even after several hours, whereas 1 reacts photochemically
(Philips HPK 125; Pyrex filter) with 3a within a few minutes. (s-cis-Butadiene)zirconocene 2 also proves to be no
Photochemical Isomerization by
Intramolecular Diels-Alder Reaction
By Hans-Dieter Beckere, Kjell Sandros, and
Kjell Andersson
Dedicated to Professor Giinther 0. Schenck on the
occasion of his 70th birthday
As part of a study of the relationship between molecular
geometry and excited state reactivity, we recently prepared
cis- 1,2-di(9-anthryl)ethylene 1 in order to compare its photochemical and photophysical properties with those of its
trans-isomer 2[1-31. Attempts to induce photochemical
trans+cis isomerization were not successful, but irradiation of 1 in cyclohexane (1> 300 nm) produced the transisomer 2 in nearly quantitative yield, together with small
amounts of the [4n. 4.111cycloaddition product 3IZ1.At low
conversion of 1, however, equal quantum yields (0.0007)
were estimated for both the geometrical isomerization to 2
and the cycloaddition to 3.
Fig. 1. Structure of 4a in the crystal. Selected bond lengths
1.946(4), Zr-CI 2.311(7), Cl-C2 1.468(9), C2-C3 1.351(9), C3-C4 1.498(8);
bond angles ["I: Zr-0-C5 150.5(4), 0-Zr-CI 91.9(2).
longer inert towards 3a: on reaction with the mixture of
the isomers 1 and 2, 2 is consumed at a similar rate as 1,
with formation of 4a.
These observations suggest that-analogous to the reaction of 1+ 2 with 0lefins[~~-4is formed from the intermediary product (q2-butadiene)zirconocene719]oia the intermediates 8 and 9 . Therefore, it appears that the selectivity
control of the zirconocene-induced coupling of conjugated
dienes with aldehydes and ketones may in some cases depend decisively on the formation and properties of intermediary (q2-diene)metallocene complexes"01.
Received: February 2, 1983 [Z 265 IE]
German version: Angew. Chem. 95 (1983) 506
The complete version of this communication appears in:
Angew. Chem. Suppi. 1983, 675-690
(21 G. Erker, J. Wicber, K. Engel, F. Rosenfeldt, W. Dietrich, C. Kriiger, J.
A m . Chem. Soc. 102 (1980) 6344; G. Erker, J. Wicher, K. Engel, C.
Kxiiger, A.-P. Chiang, Chem. Ber. 115 (1982) 3300, 3311.
131 H. Yasuda, Y. Kajihara, K. Mashima, K. Nagasuna, A. Nakamura,
Chem. Leti. 1981, 671.
I41 G. Erker, K. Engel, U. Dorf, J. L. Atwood, W. E. Hunter, Angew. Chem.
94 (1982) 915,916; Angew. Chem. Inf. Ed. Engl. 21 (1982) 913,913; Angew. Chem. Suppl. 1982, 1974, 1984.
(91 U. Dorf, K. Engel, G. Erker, O r g u n o m e f u l h 2 (1983) 462.
1101 A. Stockis, R. Hoffmann, J. A m . Chem. SOC.102 (1980) 2952; V. Skibbe,
G. Erker, J. Orgunomei. Chem. 241 (1983) 15.
Angew. Chem. Int. Ed. Engi. 22 (1983) No. 6
We have now investigated the wavelength dependence
of the photochemical isomerization of 1 and found a novel
intramolecular cycloaddition in which the 1,2-bond of an
anthracene n-system participates as a dienophile in a
Diels-Alder reaction.
Irradiation of 1 (20 mg) in cyclohexane (900 mL) at
50 "C for 6 h under argon (A> 392 nm) results in complete
isomerization. After separation of the trans-isomer 2 (37%
yield) 3 remains and, surprisingly, the novel dissymmetric
photo-isomer 4 (500/0 yield, colorless crystals, m.p. ca.
180 "C, decomp.).
The high-resolution mass spectrum, the 270 MHz 'HNMR spectrum, and the electronic absorption spectrum
are consistent with the structure 4 (Fig. 3a). Evidence for
this structure was also obtained by dehydrogenation with
(DDQ), which afforded the triptycene derivative 5 (yellow crystals, m.p.
293°C). The structure of 5 is supported by its 'H-NMR
spectrum and by its electronic absorption spectrum, which
[*] Dr. H.-D. Becker, Dr. K. Sandros, K. Andersson
Departments of Organic and Physical Chemistry
Chalmers University of Technology and University of Gothenburg
S-41296 Gothenburg (Sweden)
0 Veriug Chemie GmbH, 6940 Weinheim, 1983
0570-0833/83/0606-0495 $02.50/0
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carbonyl, induced, compounds, zirconocene, couplings, butadiene
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