Hydrosilylation, trichlorosilane reduction

In all of these cases, paUadium-catalyzed hydrosilylation proceeds via hydropalla-dation followed by reductive elimination of alkyl- and silyl group from the palladium. In the reaction of o-aUylstyrene (24) with trichlorosilane, which gives hydrosilylation products on the styrene double bond 25 and cycUzed product 26, the hy-dropalladation process is supported by the absence of side products which would result from the intermediate of the silylpaUadation process (Scheme 3-11) [37]. 

Not surprisingly, chiral formamides emerged as prime candidates for the development of an asymmetric variant of this reaction. A selection of the most efficient amide catalysts based on amino acids is shown in Figure 7.4 representative examples of enantioselective hydrosilylation are collected in Tables 7.7 and 7.8. Proline-derived anilide 82a and its naphthyl analogue 82b, introduced by Matsu-mura [3c], produced moderate enantioselectivity in the reduction of aromatic ketimines with trichlorosilane at 10 mol% catalyst loading (Table 7.7, entries 1 and 2). Formamide functionality proved to be crucial for the activation of the silane, as the corresponding acetamides failed to initiate the reaction. 

Reduction via hydrosilylation with trichlorosilane does not requires a metal. Asymmetric reduction is achieved in the presence of the picolinic amide of (lR,25)-ephedrine, or an... 

Keywords Transfer hydrogenation Organocatalysis Hantzsch ester Trichlorosilane Phosphoric acid Aminocatalysis Thioureas Lewis bases Reduction Hydrosilylation... 

A well-defined iron hydride complex FeH(CO)(NO)(Ph3P)2 is highly active as a catalyst for selective hydrosilylation of internal alkynes to vinylsilanes. Depending on the silane employed, either E- or Z-selective hydrosilylation products are formed in excellent yields and good to excellent stereoselectivities. The stereochemical course of this transformation is dependent on the steric demand of the substituents on the silane. " A new 0 family of Lewis-basic 2-pyridyloxazolines catalyses the enantioselective reduction of prochiral aromatic ketones and ketimines using trichlorosilane. 1-Isoquinolyloxazoline (20) derivative was identified as the most efficient catalyst of the series capable of delivering high enantioselectivities in the reduction of both ketones (up to 94% ee) and ketimines (up to 89% (p)... 

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