The reactions of a series of half-sandwich trihydrides of ruthenium, Cp*(R 3 P)Ru(H) 3 (R 3 P ) Pr i 3 P, Pr i 2 MeP, Pr i Me 2 P, PhMe 2 P), with a family of chlorosilanes (ClSiHMe 2 , Cl 2 SiHMe, Cl 3 SiH) have been studed with the aim of preparing the dihydridesilyl derivatives Cp*-(R 3 P)Ru(H) 2 (SiR 3 ). The reaction of Cp*(R 3 P)Ru(H) 3 with ClSiHMe 2 occurs at 90 °C and gives two types of products, Cp*(R 3 P)Ru(H) 2 (SiClMe 2 ) (1) and Cp*(R 3 P)Ru(H) 2 (SiCl 2 Me) (2). The yield of complexes 2 increases with the decrease of the size of the phosphine ligand. X-ray structures of Cp*(Pr i 3 P)Ru(H) 2 (SiClMe 2 ) (1a) and Cp*(Pr i 2 MeP)Ru(H) 2 (SiClMe 2 ) (1b) are consistent with the presence of interligand hypervalent interactions Ru-H‚‚‚Si-Cl. The compounds Cp*(R 3 P)Ru(H)(Cl)(SiCl 2 Me) (3) were prepared by the reaction of Cp*(R 3 P)Ru-(H) 3 with Cl 2 SiHMe at 60 °C and characterized by NMR and IR spectroscopy.

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Three-Component Reactions of Tetranitromethane with Olefins. -The reaction of tetranitromethane with two different olefins provides access to dinitroisoxazolidine derivatives in moderate yields. Key feature of the reaction is the use of a tri-or tetra--substituted olefin with a nucleophilic C-C double bond in the first step, which is able to react with tetranitromethane (II) to give a nitronic ester that is a poor 1,3-dipolarophile for the cyclization step. Good results are achieved with bicyclobutylidene (I) and 1-substituted cycloalkenes while dimethylbutene (XV) is less suitable. A wide range of olefins including electron-rich or electron-poor olefins can be used in the second step for the cyclization. Mixtures of diastereomers are obtained in most cases due to hindered rotation around the nitrogen. -(AVERINA, E. B.; BUDYNINA, E. M.; IVANOVA, O. A.; GRISHIN, Y. K.; GERDOV, S. M.; KUZNETSOVA, T. S.; ZEFIROV, N. S.; Russ.