As chiral ligands for transition metal complex catalyzed asymmetric reactions, various kinds of chiral ferrocenylphosphines, which have planar chirality due to 1,2-unsymmetrically substituted ferrocene structure and also have a functional group on the side chain of the ferrocene nucleus, were prepared. (S)-N,N-dimethyl-1-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine [(S)-(R)-PPFA], (S)-N,N-dimethyl-1-[(R)-1′,2-bis(diphenylphosphino)ferrocenyl]ethylamine [(S)-(R)-BPPFA], and their dimethylphosphino derivatives were prepared by way of lithiation of optically resolved N,N-dimethyl-1-ferrocenylethylamine. The 1-(dimethylamino)ethyl group on the ferrocenylphosphines was converted stereospecifically by nucleophilic substitution reactions into 1-methoxy-, 1-hydroxy-, 1-diphenylphosphino-, and several 1-(dialkylamino)ethyl groups. 1-Diphenylphosphino-2-(dimethylaminomethyl)ferrocene (FcPN) was optically resolved via its phosphine sulfide dibenzoyltartaric acid salt. The relationship between CD spectra of the chrial ferrocenylphosphines and the configuration of their planar chirality is discussed.
New C2-symmetric silylene-bridged metallocene compounds, [Me2Si(η5-RnC5H4−n)(η5-R′nC5H4−n)]MCl2 (M = Zr, Hf; Rn, R′n = Me, t-Bu, 2,4-Me, 2,3,5-Me3), were synthesized together with C1-symmetric ones (M = Zr, Hf; Rn = 2,3,5-Me3, 2,4-Me2, 3,4-Me2, t-Bu, Me; R′n = Me, H) for comparison and employed as the catalysts for isotactic polymerization of propylene in combination with methylaluminoxane. The C2-symmetric metallocenes bearing methyl groups at 2- or 5-positions gave polymers of the highest melting point (160–163 °C) and stereospecificity ([mmmm]: 97–99%).
In the oligomerization of propylene by (C5Me5)2MCl2 (M = Zr,Hf)/methylalumoxane, formation of abnormal oligomers such as 1-pentene(C5), 2,4-dimethyl-1-pentene(C7), 4-methyl-1-heptene(C8), and 2,4,6-trimethyl-1-heptene(C10) besides normal oligomers such as 4-methyl-1-pentene(C6) and 4,6-dimethyl-1-heptene(C9) is indicative of the mixing of unusual β-CH3 and usual β-H transfer terminations from each growing carbon chain which was initiated by insertion of propylene into either M–H or M–Me bond.
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