(-)-[Ethylene-1,2-bis(h5-4,5,6,7-tetrahydro-1-indenyl)]zirconium (R)-1,1-Bi-2,2-naphtholate1

[133868-91-4]  · C40H36O2Zr  · (-)-[Ethylene-1,2-bis(h5-4,5,6,7-tetrahydro-1-indenyl)]zirconium (R)-1,1-Bi-2,2-naphtholate  · (MW 639.98)

(in combination with methylaluminoxane it is an enantioselective hydrogenating2 and cyclopolymerizing agent;3 reagent for the resolution of racemic ethylenebis(tetrahydro-1-indenyl)]zirconium dichloride4)

Physical Data: [a]25436 -1761° (c 1.1, CHCl3).

Preparative Methods: this reagent is an intermediate for the preparation of optically pure ethylenebis(tetrahydro-1-indenyl)zirconium dichloride.4 That is, according to the procedure described for the kinetic resolution of ethylenebis(tetrahydro-1-indenyl)titanium dichloride with (R,R)- or (S,S)-binaphtholate,5 1 equiv of racemic ethylenebis(tetrahydro-1-indenyl)zirconium dichloride6 can be resolved with 0.5 equiv of (R,R)-binaphthol in the presence of sodium metal in toluene to yield the optically active (S,S)-ethylenebis(tetrahydro-1-indenyl)zirconium dichloride and the (-)-[ethylenebis(tetrahydro-1(R)-indenyl]zirconium (R)-binaphtholate. The separated optically pure (-)-[ethylenebis(tetrahydro-1(R)-indenyl]zirconium (R)-binaphtholate can be easily converted to the corresponding optically pure zirconocene dichloride upon treating with HCl gas.

Catalytic Hydrogenation and Cyclopolymerization.

This zirconium reagent constitutes a homogeneous catalytic system (Ziegler-Natta catalyst) with methylaluminoxane (MAO) for the purpose of enantioselective hydrogenation2 of alkenes or cyclopolymerization3 of alkenic compounds to optically active polymers. In the hydrogenations, terminal alkenes substituted in the 2- or 3-positions and internal alkenes are hydrogenated with 23-65% ee in good yields. In the catalytic deuteration of styrene with this reagent, the re-face of styrene is deuterated in 65% optical purity (eq 1). This enantioselectivity in hydrogenation is opposite to propylene oligomerization with the same catalytic system. 1,5-Hexadiene is polymerized with this catalytic system in 91% enantioface selectivity to give poly(methylene-1,3-cyclopentane) (PMCP), which is inductive of a highly isotactic microstructure (eq 2). The absolute configuration of the polymer is tentatively assigned on the basis of the sign of the optical rotation of the model compound trans-(1R,3R) 1,3-dimethylcyclopentane.3

Related Reagents.

(R,R)-[Ethylene-1,2-bis(h5-4,5,6,7-tetrahydro-1-indenyl)]titanium (R)-1,1-Bi-2,2-naphtholate; (±)-1,1-Ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium Dichloride.

1. Halterman, R. L. CRV 1992, 92, 965.
2. Waymouth, R.; Pino, P. JACS 1990, 112, 4911.
3. Coates, G. W.; Waymouth, R. M. JACS 1993, 115, 91.
4. (a) Grossman, R. B.; Davis, W. M.; Buchwald, S. L. JACS 1991, 113, 2321. (b) For the improved procedure of resolution, see; Schäfer, A.; Karl, E.; Zsolnai, L.; Huttner, G.; Brintzinger, H. H. JOM 1987, 328, 87.
5. Wild, F. R. W. P.; Zsolnai, L.; Huttner, G.; Brintzinger, H. H. JOM 1982, 232, 233.
6. (a) Wild, F. R. W. P.; Wasiucionek, M.; Huttner, G.; Brintzinger, H. H. JOM 1985, 288, 63. (b) Collins, S.; Kuntz, B. A.; Taylor, N. J.; Ward, D. G. JOM 1987, 342, 21. (c) Ewen, J. A.; Haspeslagh, L.; Atwood, J. L.; Zhang, H. JACS 1987, 109, 6544. (d) Grossman, R. B.; Doyle, R. A.; Buchwald, S. L. OM 1991, 10, 1501.

Takeo Taguchi & Yuji Hanzawa

Tokyo College of Pharmacy, Japan

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