Yoichiro Nagai

Hydrosilylation of α,β-unsaturated nitriles and esters catalyzed by tris (triphenylphosphine)chlororhodium

Abstract The hydrosilylation of α,β-unsaturated nitriles and esters such as acrylonitrile, crotononitrile, cinnamonitrile, ethyl and methyl acrylate, ethyl and methyl crotonate and ethyl and methyl methacrylate using tris(triphenylphosphine)chlororhodium as a catalyst is described. The hydrosilylation of α,β-unsaturated nitriles provided α-adduct exclusively in high yield except in the case of trichlorosilane which afforded β-adduct with acrylonitrile. On the other hand, the hydrosilylation of α,β-unsaturated esters gave rather complex results. The selectivity of the reactions was dramatically affected by the substituent of the ester group and that on the β-carbon. Thus, the hydrosilylation of ethyl acrylate with triethylsilane afforded a β-adduct, but, that of ethyl crotonate using the same hydrosilane gave a 1,4-adduct exclusively. Possible mechanisms for these reactions are discussed.

Reaction of disilanes with acetylenes : II. Double silylation of 1-hexyne, trimethylsilylacetylene and acetylene with methoxymethyldisilanes catalyzed by tetrakis(triphenylphosphine)palladium

Abstract In the presence of a palladium(0) complex catalyst, methoxymethyldisilanes, (MeO) n Me 3-n SiSiMe 3-m (OMe) m ( m , n  1, 2), added to 1-hexyne, trimethylsilyl-acetylene and acetylene to give double silylation products, 1,2-bis(methoxy-methylsilyl)olefins, in varying yields.

Conversion of disilanes to functional monosilanes : III. Preparation of allylmethylsilanes by tetrakis(triphenylphosphine)- palladium(O)-catalyzed reactions of methylchlorodisilanes with allylic halides.☆

Abstract Various allylmethylsilanes were prepared by the reactions of methylchlorodisilanes with allylic halides catalyzed by tetrakis(triphenylphosphine)- palladium(O).

Conversion of disilanes to functional monosilanes : Preparation of some nitrophenyltrimethylsilanes by tetrakis(triphenylphosphine)palladium(O) catalyzed reactions of hexamethyldisilane with nitrohalobenzenes

Abstract o -, m - and p -Nitrophenyltrimethylsilanes and 2,4-dinitrophenyltrimethylsilane were conveniently prepared by the reactions of hexamethyldisilane with the corresponding nitrohalobenzenes catalyzed by tetrakis(triphenylphosphine)-palladium(O).

The stereoselective addition of phenyldimethylsilane to phenylacetylene catalyzed by rhodium triphenylphosphine complexes

Abstract Tris(triphenylphosphine)chlororhodium was found to be an effective catalyst for the hydrosilylation of phenylacetylene. Trans addition of phenyldimethylsilane gave cis products, but concomitant cis addition leading to trans products occurred to some extent. Under certain conditions, complete isomerization of the cis to the trans isomer of the product was also observed during the hydrosilylation. In the hydrosilylation employing bis(triphenylphosphine)carbonylchlororhodium as catalyst the stereoselective reaction proceeded at faster rates than those using the above rhodium complex and no isomerization occurred.

Preparation of dimethyltetramethoxydisilane from the disilane fraction

Abstract Reaction of sym-dimethyltetrachlorodisilane, obtained by chlorination with hydrogen chloride of the higher-boiling residue produced in the Direct Synthesis of methylchlorosilanes, with methyl orthoformate or methanol/methyl orthoformate gave rise to sym-dimethyltetramethoxydisilane.

Silicon—carbon bond formation by the reaction of disilanes with halobenzenes in the presence of tetrakis(triphenylphosphine)palladium(0)

Abstract Cleavage of disilanes with halobenzenes such as bromobenzene and chlorobenzene to afford arylsilanes was found to occur under the catalytic influence of tetrakis(triphenylphosphine)palladium(0).

The stereochemistry of the addition of hydrosilanes to alkyl acetylenes catalyzed by tris(triphenylphosphine)-chlororhodium

Abstract Tris(triphenylphosphine)chlororhodium was found to be an effective catalyst for the hydrosilylation of acetylenes. An unusual stereochemistry of addition was observed in the reaction of alkylacetylenes with hydrosilanes; the rhodium-catalyzed reaction involves a stereoselective trans addition.

Group VIII metal phosphine complexes-catalyzed addition of disilanes to allenic compounds: Formation of new organosilicon compounds containing both vinylsilane and allylsilane units

Abstract Addition of chloromethyl- and methoxymethyldisilanes, X3-mMemSiSiMen-X3-n (X - Cl and OMe;m, n - 0-2), as well as hexamethyldisilane, to allene and 1, 2-butadiene in the presence of Pd(PPh3)4 catalyst gave regioselectively new functionalized organosilicon compounds, 2, 3-bis(organosilyl)prop-1-enes and 2, 3-bis(organosilyl)but-1-enes, respectively. Other group VIII metal-phospine complexes also affected the reaction, but results were found to be less satisfactory. Also, the reaction of any unsymmetrical disilane with an allenic compound gave only a single product; e.g., the addition of chloropentamethyldisilane to 1, 2-butadiene in the presence of Pd(PPh3)4 gave CH2-C(SiMe3)CH(SiMe2Cl)Me in 93% yield.

Addition of chlorodisilanes to 1,3-butadienes in the presence of tetrakis(triphenylphosphine)palladium(0). A facile route to (Z)-1,4-bis(chlorosilyl)but-2-enes

Abstract In the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0), chlorodisilanes of type MenSi2Cl6-n (n  0, 2, 3 and 4) add to 1,3-butadienes to give (Z)-1,4-bis(chlorosilyl)but-2-enes.