Organosilicon compounds vinyl groups

Hydrosilylation of unsaturated organosilicon compounds has also found several applications in molecular and polymer organosilicon chemistry. In particular, the addition of polyfunctional silicon hydrides to poly(vinyl)organosiloxane, catalyzed exclusively by Pt compounds and providing an activated cure for silicon rubber [10], has been of great practical importance. Hydrosilylation of the vinyl group at silicon seems to be effective synthetic method for preparation of oligomers and polymers with a linear or cyclolinear stmcture (polyhydrosilylation), and can occur either via the addition of dihydro-carbosilanes and -siloxanes to divinyl-silanes and -siloxanes [25, 26] or by intermolecular hydrosilylation [4] (eq. (1)). 

Analogously, starting from appropriate silicon halides or alkoxides and introducing various alkyl, aryl, or alkenyl groups stepwise leads to racemic organosilicon compounds such as methyl-(l-naphthyl)(phenyl)silane297 and methoxy-(l-naphthyl)(phenyl)(vinyl)silane298 which can be separated into their enantiomers. 

Other Direct Functionalization Reactions. In addition to the above processes, other direct functionalization reactions at the molecular level include the addition of organosilicon hydrides to allyl groups at the terminus of aryloxy side groups (56), the free-radical grafting of epoxy-, organosilyl-, or pyridine-bearing vinyl compounds to p-methylphenoxy side units (57), the quatemization of pendent tertiary amino groups, and... 

Summary Recent achievements in two catalytic reactions, i.e., silylative coupling and cross-metathesis of alkenes and dienes with vinyl-silicon compounds, which resulted in new synthetic routes to organosilicon molecular and macromolecular compounds are presented. The silylative coupling, also called dehydrogenative or trans-silylation and silyl group transfer, is catalyzed by metal complexes which either contain or initiate the formation of M-H and M-Si bonds, where M = Ru, Rh, Co and Ir. Cross-metathesis, which was developed very recently, proceeds in the presence of metallacarbenes, mainly those of rathenium (e.g., Grabbs catalyst). 

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