Stereochemie von Metallocenen, 42. Mitt.: Optisch aktives π-Fluorenon-tricarbonylchrom — Darstellung, enantiomere REinheit, absolute Konfiguration und Versuche zur Racemisierung
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Stereochemistry of metallocenes, 42: optically active π-fluorenone tricarbonylchromium—preparation, enantiomeric purity, absolute configuration and attempts tempts of racemization
Abstract
Racemic Fluorenone-Cr(CO)3 (1) was prepared from fluorenone ethyleneketal by complexation with Cr(CO)6 and subsequent cleavage of the dioxolane9. Asymmetric reduction of1 with a chiral Lithium hydride afforded both (+)-1 and the correspondingendo-carbinol (−)-7 a with optical yields up to 80% as established by the use of chiral nmr shiftreagents. Active1 could also be obtained by two other asymmetric reactions albeit with low optical yields. LiAlH4−AlCl3 reduction of (+)-1 gave traces of (+)-fluorene-Cr(CO)3 (2).
The absolute chirality of (+)-1 was deduced as (S) by application of the abovementioned asymmetric reduction to ferroceno indenone (11) of known configuration and byHoreau's method to (−)-7 a. Several attempts to racemize1 failed, which proves that no transanular shift of Cr(CO)3 takes place. The CD spectra of1 and2 are reported.
Some side reactions such as the reduction of7 a to2 with Cr(CO)6 in dibutylether (leading also to the formation of isomeric dimethylbenchrotrenes from the solvent) and the formation of a binuclear complex14 between1 and2 are briefly reported.
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- 2.F. A. Adedeji, D. L. S. Brown, J. A. Connor, M. L. Leung, I. M. Paz-Andrade undH. A. Skinner, J. Organometal. Chem.97, 221 (1975).Google Scholar
- 3.G. Jaouen undR. Dabard, Tetrahedron Lett.1971, 1015;V. N. Trembovler, N. K. Baranetskaya, N. V. Fok, G. B. Zaslavskaya, B. M. Yavorskii undV. N. Setkina, J. Organometal. Chem.117, 339 (1976).Google Scholar
- 4.G. Jaouen undA. Meyer, J. Amer. Chem. Soc.97, 4667 (1975).Google Scholar
- 5.A. Meyer, H. Neudeck undK. Schlögl, Chem. Ber.110, 1403 (1977).Google Scholar
- 6.A. Meyer undG. Jaouen, J. Organometal. Chem.97, C-21 (1975).Google Scholar
- 7.H. Lehner undK. Schlögl, Mh. Chem.101, 895 (1970) und102, 277 (1971).Google Scholar
- 8.G. Brule undJ.-Y. LeBihan, C. r. acad. sci. Paris274, 1218 (1972).Google Scholar
- 9.E. O. Fischer undN. Kriebitzsch, Z. Naturforsch15 b, 465 (1960).Google Scholar
- 10.M. Le Plouzennec undR. Dabard, J. Organometal. Chem.133, 359 (1977).Google Scholar
- 11.K. Schlögl undH. Falk, in: Methodicum Chimicum (F. Korte, Hrsg.), Bd.8, S. 433. Stuttgart: G. Thieme. 1974; und S. 469. New York: Academic Press. 1976.Google Scholar
- 12.Vgl. z. B.:W. R. Jackson undT. R. B. Mitchell, J. Chem. Soc. (B),1969, 1228;G. Jaouen undR. Dabard, Bull. soc. chim. France1974, 2009.Google Scholar
- 13.J. D. Morrison undH. S. Mosher, Asymmetric Organic Reactions, S. 202. Englewood Cliffs, N.J.: Prentice-Hall. 1971.Google Scholar
- 14.J. P. Vigneron undJ. Jacquel, Tetrahedron32, 939 (1976).Google Scholar
- 15.Vgl.K. Schlögl, in: Methodicum Chimicum (F. Korte, Hrsg.), Bd.1/1, S. 235. Stuttgart: G. Thieme. 1973.Google Scholar
- 16.K. Schlögl, in: Topics in Stereochemistry (N. L. Allinger undE. L. Eliel, Hrsg.), Bd.1, S. 39. New York: Interscience. 1967.Google Scholar
- 17.K. M. Nicholas, R. C. Kerber undE. I. Stiefel, Inorg. Chem.10, 1519 (1971).Google Scholar
- 18.B. Nicholls undM. C. Whiting, J. Chem. Soc.1959, 551.Google Scholar
- 19.J. Gombos, E. Haslinger undU. Schmidt, Chem. Ber.109, 2645 (1976).Google Scholar