Takatoshi Hayashi

STUDIES ON FERROCENE DERIVATIVES. XV. HYDROLYSIS OF DIESTERS CONTAINING A FERROCENE NUCLEUS

ABSTRACT The hydrolysis of 1,1′-bis[ω-(methoxycarbonyl)alkanoyl]ferrocenes was carried out. In the compounds which have the same 1- and 1′-substituents, the values of k1 and k2 were different. This may be caused by the electrostatic interaction between the two carbonyl groups.

Studies on ferrocene derivatives. Part XVI: steric effects on the ligand exchange reactions of alkylferrocenes

Ligand exchange reactions of alkylferrocenes with substituted benzenes were carried out. The steric effects of substituents on the reaction were almost equal irrespective of the site of the substituents, either on the cyclopentadienyl – or the benzene ring. For benzene ring substituents, the effect on the symmetrically substituted benzenes was greater than that on the unsymmetrically substituted benzenes.

Monophenylation accompanied by partial reduction of 1,1-dihalogeno-2-phenyl-1-alkenes in the presence of a nickel-phosphine complex

Abstract Reaction of 1,1-dihalogeno-2-phenyl-1-alkenes (I) with phenylmagnesium bromide in the presence of NiCl 2 (dppp) in THF has been studied. Mono-cross-coupling accompanied by partial reduction gave ( E )-1,2-diphenyl-1-alkenes (III) as the major products. Use of a large excess of Grignard reagent increased the yields of III and the ( Z )-isomers (II), with a decrease in the yield of double cross-coupling products, 1,1,2-triphenyl-1-alkenes (IV). The highest ratio of the sum of the yields of the monophenylation products to the yield of the double cross-coupling product, (II + III)/IV = 36.5, was found for the reaction of PhMgBr with 1,1-dibromo-2-phenylpropene (Ib) in a 12.0/1 molar ratio. A possible reaction mechanism is described.

Study on Phase Transition in Liquid Crystalline Side-Chain Polymers

Abstract Five series of copolymers of cholesteryl 11-methacryloyloxyalkanoate (ChMO-10) with non-mesogenic monomers (t-butyl methacrylate and n-alkyl methacrylates (carbon number n; n=1, 4, 12, 18)) were studied by DSC method. In each copolymer, the clearing point (Tcl) decreases gradually with decreasing the molar fraction of ChMO-10. The slope of the Tcl curve becomes steeper with increasing the length of the non-mesogenic n-alkyl chain, but few difference is observed between the compounds with 12 and 18 carbon atoms of the non-mesogenic group. In the case of the copolymer with t-butyl methacrylate, the slope of the Tcl curve is steeper than that of the copolymer with n-butyl methacrylate. Consequently, the Tcl was affected by the effects of both the chain length and the bulkiness of non-mesogenic group.

Studies on ferrocene derivatives. Part XIV: Oxidation reaction of (2,6-disubstituted phenyl)ferrocenes

Abstract The oxidation rate of (2,6-disubstituted phenyl)ferrocenes is increased compared with other disubstituted analogues due to a tilting of cyclopentadienyl rings, which in turn increases the basicity of the iron.

Studies on ferrocene derivatives. Part XIII. Ligand exchange reactions of benzoferrocenes

Reactions between benzoferrocenes and substituted benzenes gave products resulting from intramolecular and intermolecular ligand exchange. The product ratios were influenced by the number of methyl substituents on the benzene ring; the larger the number, the greater the ratio of intermolecular products.

Studies on ferrocene derivatives. Part 12. Substituent effects for the disproportionation, synproportionation and ligand exchange reactions of t-butylferrocenes

SummaryThe disproportionations and synproportionations of t-butylferrocenes and the ligand exchanges between the ferrocenes and benzene have been studied. The steric effects of the t-butyl groups were found to significantly affect the ratio of the products obtained. In these reactions, aluminium chloride attacks and abstracts the cyclopentadienyl ring. As a result, the ferrocene molecule decomposes into two fragments. The aluminium chloride selectively attacks the least sterically hindered cyclopentadienyl ring. The steric effect for a cyclopentadienyl ring bearing two t-butyl groups is substantial and inhibits attack by aluminium chloride. The product therefore contains the cyclopentadienyl ring which has the higher steric hindrance (i.e. the 1,3-di-substituted cyclopentadienyl ring).