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研究, 岩下 正弘教授 古希祝賀記念号

The catalyzed reaction of an excess of styrene with n-Bu3GeH using several ruthenium and rhodium complexes gave the corresponding vinylgermanes (α-tri-n-butylgermylstyrene, (Z)-β-tri-n-butylgermylstyrene, and (E)-β-tri-n-butylgermylstyrene), which are dehydrogenative germylation products. The most effective catalyst was Ru3(CO)12, whose use resulted in selective formation of the vinylgermanes in high yields.

An attempt has been made to synthesize structurally reinforced chiral B2-18-membered hexaazamacrocyclic amine based dinuclear copper(?) complexes 2 and 2′ as models for studying the size-match selectivity of metal ions. These two dinuclear complexes have manifested a prominent difference in the electronic spin structure, although only apparent structural difference is subtle. The complex 2 is double-bridged with an oxygen and chloride atom while 2′ is single-bridged only with the oxygen atom of hydroxide ion and the fifth ligand Cl is missing. From cw ESR measurements of 2 and 2′ in polycrystalline solids a large zero-field splitting (ZFS) value has been determined for 2′ and a small ZFS value for 2, respectively. These findings have been in accordance with the results from the SQUID measurements. The ZFS values and isotropic exchange interaction have been theoretically estimated on the basis of molecular structural considerations of the complexes. The ground-state spin structures for the complex...

We have attempted to synthesize structurally reinforced chiral B2-18-membered hexaazamacrocyclic amine based dinuclear copper(II) complexes 2 and 2′ as models for studying the size-mach selectivity of metal ions. From the viewpoint of molecular based magnetism-structure relationship, these two dinuclear complexes have manifested a prominent difference in the electronic structure, although only apparent structural difference is subtle. In the dinuclear complex 2′, the fifth ligand is missing, forming slanting bi-squares with a common oxygen atom of hydroxide ion. CW ESR measurements of 2 and 2′ in polycrystalline solids have shown that a triplet fine-structure spectrum with a large zero-field splitting (ZFS) value features in 2′ and an exchange coupled copper(II) pair spectrum does in 2, respectively. These findings have been expounded in connection with the structural difference in the macrocyclic rugbyball-shaped cavity of the ligand. The ground-state spin multiplicity for the copper dinuclear c...

We have synthesized structurally reinforced chiral pentaaza-fifteen-membered polyamines 1 and 2 with a dibridge for the purposes of studying the size-match selectivity of the macrocyclic cavity. Particularly, an attempt has been made to synthesize copper(II) complexes of 1 and 2 to characterize the size-match selectivity of the polyamines in term of microscopic details of the metal-ion binding site. For this purpose the use of ESR spectroscopy has been invoked before X-ray structural analyses of the complexes are carried out. Powder-pattern ESR spectra of the copper(II) complex of 1 in crystalline solid have revealed a temperature dependence of the copper hyperfine structure. This finding suggests that a vibronic effect features in the hyperfine spectra, showing that the pentaaza-macrocycle under study accommodates copper(II) ion and the macrocycle is flexible to exert “genuine” size-match selectivity.

Two structurally reinforced chiral 15-membered azamacrocycles (2S, 14S)-2,14-diisobutyl-10-methyl-1,4,7,10,13 -pentaazabicyclo[11.2.2]heptadecane and (2S,14S)-2,14-diisobutyl-7,10-dimethyl-1,4,7,10,13-pentaazabicyclo[11.2.2] heptadecane as a new type of ligand were conveniently synthesized by LiA1H4 reduction from their corresponding macrocyclic pseudopeptides cyclo[(2S,3′S)-2-(3′-isobutyl-2′-oxopiperazine-1′-yl)-4-methyl-pentanoyl-glycyl-glycyl-sarcosyl] and cyclo[(2S, 3′S)-2-(3′-isobutyl-2′-oxopiperazine -1′-yl)-4-methyl-pentanoyl-glycyl-sarcosyl-sarcosyl], respectively. Their copper(II) complexes were also prepared and characterized.

The Co2(CO)8-catalyzed reaction of 1-hexene with diethylmethylsilane and carbon monoxide gave high total yields of four isomers of enol silyl ethers (regio- and stereoisomers) as the results of CO incorporation. The effects of changes in reaction conditions (CO pressure, molar ratio of the reactants, and temperature) on the isomer composition were studied. The catalytic activity of various transition metal complexes was examined and Co2(CO)8, Ru3(CO)12, and RhCl(PPh)3)3 shown to be effective. The catalyzed reaction of methyl acrylate also gave the corresponding enol silyl ethers. The Co2(CO)8-catalyzed reaction of 1,5-hexadiene with a hydrosilane and carbon monoxide afforded a cyclic compound in addition to straight-chain enol silyl ethers.

Dehydrogenative silylation of olefins, such as styrenes, methyl acrylate, and vinyl ether, using allyltriethoxysilane as the source of the silyl group can be catalyzed by RuHCl(CO)(PPh3)3 to give t...

The catalyzed reaction of an excess of styrene with n-Bu3GeH using several ruthenium and rhodium complexes gave the corresponding vinylgermanes (α-tri-n-butylgermylstyrene, (Z)-β-tri-n-butylgermylstyrene, and (E)-β-tri-n-butylgermylstyrene), which are dehydrogenative germylation products. The most effective catalyst was Ru3(CO)12, whose use resulted in selective formation of the vinylgermanes in high yields.

Heteroarylsilanes can be synthesized by the reaction of heteroaromatic compounds with triorganovinylsilanes with the aid of a Ru3(CO)12-catalyst. A variety of heteroaromatic compounds can be used in this C–H/SiR3 coupling. The coupling reaction was observed to take place at a position β to the directing carbonyl group, e.g., ketone, ester, and amide, in the case of heteroaromatic compounds.

The Co2(CO)8-catalyzed reaction of 1-hexene with diethylmethylsilane and carbon monoxide gave high total yields of four isomers of enol silyl ethers (regio- and stereoisomers) as the results of CO incorporation. The effects of changes in reaction conditions (CO pressure, molar ratio of the reactants, and temperature) on the isomer composition were studied. The catalytic activity of various transition metal complexes was examined and Co2(CO)8, Ru3(CO)12, and RhCl(PPh)3)3 shown to be effective. The catalyzed reaction of methyl acrylate also gave the corresponding enol silyl ethers. The Co2(CO)8-catalyzed reaction of 1,5-hexadiene with a hydrosilane and carbon monoxide afforded a cyclic compound in addition to straight-chain enol silyl ethers.

Heteroarylsilanes can be synthesized by the reaction of heteroaromatic compounds with triorganovinylsilanes with the aid of a Ru3(CO)12-catalyst. A variety of heteroaromatic compounds can be used in this C–H/SiR3 coupling. The coupling reaction was observed to take place at a position β to the directing carbonyl group, e.g., ketone, ester, and amide, in the case of heteroaromatic compounds.

Optically active μ-chloro and μ-hydroxo dinuclear copper(II) complexes of structurally reinforced chiral 18-membered azamacrocycle (2S,8S,11S,17S)-2,8,11,17-tetraisobutyl-1,4,7,10,13,16-hexaazatricyclo[14. 2. 2. 27,10]docosane and 20-membered one (2S,9S,12S,19S)-2,9,12,19-tetraisobutyl-1,4,8,l1,14,18-hexaazatricyclo [16. 2. 2. 28,11] tetracosane obtained by BH3 reduction from structurally constrained macrocyclic pseudopeptides were newly synthesized and characterized.

A novel chelating reagent, N,N′-ethylene-bridged (S)-histidyl-(S)-histidine methyl ester, has been synthesized by a one-step reaction of a Schiff-base of (S)-histidine methyl ester with aqueous glyoxal and sodium cyanoborohydride. Cu(II) complexes of its derivatives also have been synthesized and characterized.

Transition metal catalyzed reaction of olefins with hydrosilanes to give vinylsilanes is reviewed. Dodecacarbonyltriruthenium is an efficient catalyst of the dehydrogenative silylation. The mechanism of the reaction is discussed.

The reaction of cycloalkenes(cyclopentene, cyclohexene, cycloheptene, cyclooctene, 1-methylcyclohexene, and norbornene) with Et 2 MeSiH and carbon monoxide in the presence of Co 2 (CO) 8 gave the corresponding diethylmethylsiloxymethylenecycloalkenes. In such reactions of cyclohexene, the following hydrosilanes gave the corresponding siloxymethylenecyclohexanes: Me 3 SiH, EtMe 2 SiH, Et 2 MeSiH, Et 3 SiH, PhMe 2 SiH, Ph 2 MeSiH. Effects of the reaction conditions(the pressure of carbon monoxide, the temperature, and the molar ratio of cyclohexene to Et 2 MeSiH) were examined. The yield of diethylmethylsiloxymethylenecyclohexane increased remarkably with increasing molar ratio of cyclohexene to Et 2 MeSiH. At higher temperature, the yield of the isomerization product, 1-(diethylmethylsiloxymethyl)-cyclohex-1-ene, increased.

General features of HSiR3/CO/Co2(CO)8 catalytic reactions are discussed. This new catalytic system can bring about one-carbon chain extension reactions of olefins and various oxygen-containing compounds. The incorporated carbon monoxide is found in the products in the form of siloxymethylidene, siloxymethyl, or other carbon-functional groups. Two important catalytic species are involved. One is hydrocobalt carbonyl, which undergoes initial interaction with olefins, and the other is silylcobalt carbonyl, which reacts initially with oxygen-containing compounds. These processes lead to the formation of alkylcobalt carbonyl as the first intermediates. The subsequent course of the catalytic reaction heavily depends on the reaction conditions and the structure of the substrates, thus affording a variety of products. Accordingly, the reaction patterns may look somewhat complicated but the underlying principles are relatively simple. Common intermediates and common mechanistic features of the new catalytic reactions are discussed.

The Ru 3 (CO) 12 -catalyzed reaction of trimethylsilylethene with triethylsilane gives a mixture of ( E )-1,2-bis(trimethylsilyl)ethene and ( E )-1-triethylsilyl-2-trimethylsilylethene. The yield of ( E -1,2-bis(trimethylsilyl)ethene increases with an increase in the molar ratio of trimethylsilylethene to triethylsilane. The Ru 3 (CO) 12 -catalyzed reaction of trimethylsilylethene in the presence of a catalytic amount of triphenylsilane also gives ( E )-1,2-bis(trimethylsilyl)ethene in good yields. Triorganosilylethenes such as dimethyl(ethoxy)silylethene and triethoxysilylethene also give the corresponding ( E )-1,2-disilylethenes. The similar, catalyzed reaction of styrene with trimethylsilylethene gives 1-trimethylsilyl-2-phenylethene in good yields.

The Ru 3 (CO) 12 -catalyzed reaction of trimethylsilylethene with triethylsilane gives a mixture of ( E )-1,2-bis(trimethylsilyl)ethene and ( E )-1-triethylsilyl-2-trimethylsilylethene. The yield of ( E -1,2-bis(trimethylsilyl)ethene increases with an increase in the molar ratio of trimethylsilylethene to triethylsilane. The Ru 3 (CO) 12 -catalyzed reaction of trimethylsilylethene in the presence of a catalytic amount of triphenylsilane also gives ( E )-1,2-bis(trimethylsilyl)ethene in good yields. Triorganosilylethenes such as dimethyl(ethoxy)silylethene and triethoxysilylethene also give the corresponding ( E )-1,2-disilylethenes. The similar, catalyzed reaction of styrene with trimethylsilylethene gives 1-trimethylsilyl-2-phenylethene in good yields.

The reaction of iodobenzene with nickel carbonyl in the presence of enamines gave β-diketones in high yields.

Die Reaktion eines funffachen Uberschusses der Olefine (I) mit den Silanen (II) in Gegenwart katalytischer Mengen Ru3 (CO),2 fuhrt zu den E-Vinylsilanen (III) in hohen Ausbeuten.

General features of HSiR3/CO/Co2(CO)8 catalytic reactions are discussed. This new catalytic system can bring about one-carbon chain extension reactions of olefins and various oxygen-containing compounds. The incorporated carbon monoxide is found in the products in the form of siloxymethylidene, siloxymethyl, or other carbon-functional groups. Two important catalytic species are involved. One is hydrocobalt carbonyl, which undergoes initial interaction with olefins, and the other is silylcobalt carbonyl, which reacts initially with oxygen-containing compounds. These processes lead to the formation of alkylcobalt carbonyl as the first intermediates. The subsequent course of the catalytic reaction heavily depends on the reaction conditions and the structure of the substrates, thus affording a variety of products. Accordingly, the reaction patterns may look somewhat complicated but the underlying principles are relatively simple. Common intermediates and common mechanistic features of the new catalytic reactions are discussed.

A new synthesis of β-bromo ketones by the reaction of trimethylsilyl cyclopropyl ethers with bromine is described.

The reaction of an excess of methyl acrylate with hydrosilanes using Co2(CO)8 as a catalyst gives methyl (E)-3-silylacrylates in high yields.

The reaction of iodobenzene with nickel carbonyl in the presence of enamines gave β-diketones in high yields.