Platinum complex-catalyzed dehydrogenative double silylation of olefins and dienes with o-bis(dimethylsilyl)benzene

Light-Promoted Arylsilylation of Alkenes with Hydrosilanes

Herein, we report light-promoted photo/hydrogen atom transfer dual catalysis for arylsilylation of alkenes via the radical-radical cross-coupling with diverse hydrosilanes, which provides a simple and efficient method to prepare various organosilicon compounds with a wide range of substrate scope and good functional group tolerance under transition-metal- and chemical-oxidant-free conditions. Furthermore, the arylsilylation of alkenes can also proceed via the possible electron donor-acceptor complex under exogenous photocatalyst-free conditions.

Platinum-Catalyzed Reactions of 2,3-Bis(diisopropylsilyl)thiophene with Alkynes

The reactions of 2,3-bis(diisopropylsilyl)thiophene (1) with diphenylacetylene, phenylacetylene, trimethylsilylacetylene, and mesitylacetylene have been reported. The reactions of 1 with diphenylacetylene and phenylacetylene in the presence of a catalytic amount of tetrakis(triphenylphosphine)platinum(0) at 80 °C gave [1,4]disilino[2,3-b]thiophene derivatives. With trimethylsilylacetylene, 1 afforded two types of products arising from sp-hybridized C-H bond activation of the acetylene, together with [1,3]disilolo[4,5-b]thiophene derivatives. A similar treatment of 1 with mesitylacetylene produced two regioisomers of products arising from the C-H bond activation of mesitylacetylene. Theoretical calculations for the intramolecular reactions of 10a and 10b are also discussed.

Disilametallacyclic chemistry for efficient catalysis

Disilametallacyclic species of late transition metals behave as key intermediates for efficient catalytic reactions proceeding through new mechanisms.

Highly selective dehydrogenative silylation of alkenes catalyzed by rhenium complexes

Choosy chemicals: Rhenium(I) complexes of type [ReBr(2)(L)(NO)(PR(3))(2)] (L=H(2) (1), CH(3)CN (2), ethylene (3); R=iPr (a), cyclohexyl (b)) proved to be suitable catalyst precursors for the highly selective dehydrogenative silylation of alkenes. Two types of rhenium(I) hydride species, [ReBrH(NO)(PR(3))(2)] (4) and [ReBr(eta(2)-CH(2)=CHR(1))H(NO)(PR(3))(2)] (5), were found in the [ReBr(2)(L)(NO)(PR(3))(2)]-catalyzed dehydrogenative silylation of alkenes.Rhenium(I) complexes of type [ReBr(2)(L)(NO)(PR(3))(2)] (L=H(2) (1), CH(3)CN (2), and ethylene (3); R=iPr (a) and cyclohexyl (Cy; b)) catalyze dehydrogenative silylation of alkenes in a highly selective manner to yield silyl alkenes and the corresponding alkanes. Hydrosilylation products appear only rarely depending on the type of olefinic substituent, and if they do appear then it is in very minor amounts. Mechanistic studies showed that two rhenium(I) hydride species of type [ReBrH(NO)(PR(3))(2)] (R=iPr (4 a) and Cy (4 b)) and [ReBr(eta(2)-CH(2)=CHR(1))H(NO)(PR(3))(2)] (R(1)=p-CH(3)C(6)H(4), R=iPr (5 a), Cy (5 b); R(1)=H, R=iPr (5 a'), Cy (5 b')) are involved in the initiation pathway of the catalysis. The rate-determining steps of the catalytic cycle are the phosphine dissociation from complexes of type 5 and the reductive eliminations to form the alkane components. The catalytic cycle implies that the given rhenium systems have the ability to activate C-H and Si-H bonds through the aid of a facile redox interplay of Re(I) and Re(III) species. The molecular structures of 4 b and 5 a were established by means of X-ray diffraction studies.