Catalytic hydrosilation

Previous work (48) with homogeneous analogues showed that Si-H oxidative additions yield cis products. A cis geometry of hydride and silyl may be allowed in catalytic hydrosilation. Because the industral homogeneous hydrosilation catalyst (62) is h PtClg we tested the activity of our surface generated reagent for the reaction of Equation 24. A suspension of the catalyst was irradiated in 1-... 

Hydrogenation may be considered a specific case of the addition of H X molecules to unsaturates where X = H. There has been of late considerable interest in developing systems for which X can be a number of other elements. One of the goals of research into C-H activation (discussed in the next section) is to develop catalysts for the addition of C H bonds to unsaturates. While this goal has not been met, the addition of Si-H bonds to unsaturates may be accomplished withanumberofiridium complexes as catalysts. Although iridium complexes are not among the most active for hydrosilation, there are a number of active ones and studies into the interactions of iridium with silanes has provided useful information about important steps in catalytic hydrosilation. 

Oxidative addition of the H—Si bond is the most studied of the group IVB elements with the exception of carbon because of its relation to the industrially important catalytic hydrosilation of alkenes, alkynes and ketones. Compounds containing the Si—M bond are stable. While they are also synthesized by routes other than oxidative addition of the H—Si bond T H—Si, H—Ge and H—Sn add to transition metals ... 

The catalytic hydrosilation and hydrogenation of carbonyl compounds in the presence of chiral organometallic catalysts is an important method for the catalytic synthesis of chiral synthons. Again, the actual insertion of the carbonyl group into an M-H bond at the catalyst site is rarely observed. ... 

Homogeneous catalytic hydrosilation of polar multiple bonds such as C=0 and C=N bonds is a useful synthetic tool as a better substitute for catalytic hydrogenation. Chiral rhodium complexes are employed for the asymmetric reduction of ketones (eq(32)) [29]. 

Photoinitiated catalytic hydrosilation of acetophenone with triethylsilane occurred in the presence of 11... 

The addition of Si-H bonds to organic unsaturations such as olefins, acetylenes, and ketones is known as the hydrosilation reaction. A majority of the hydrosilation reactions are catalyzed by soluble transition-metal complexes and are known as homogeneous hydrosilation reactions [43]. Catalytic hydrosilation reactions are known to be very complex reactions. However, a few generalizations have been drawn about the mechanism of such reactions (Figure 15.4). Homogeneous olefin hydrosilation are presumed to start with an obligatory oxidative addition of the Si-H bond in a cis fashion to the catalytic metal [44]. This process is followed... 

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