Silicon ligands carbonyl

Platinum(II) Complexes with Carbonyl and Silicon-donor Ligands 688... 

Liquid injection molding, for silicone rubbers, 3, 674—675 Liquid ligands, in metal vapor synthesis, 1, 229 Liquid-phase catalysis, supported, for green olefin hydroformylation, 12, 855 Lithiacarbaboranes, preparation, 3, 114 Lithiation, arene chromium tricarbonyls, 5, 236 Lithium aluminum amides, reactions, 3, 282 Lithium aluminum hydride, for alcohol reductions, 3, 279 Lithium borohydride, in hydroborations, 9, 158 Lithium gallium hydride, in reduction reactions, 9, 738 Lithium indium hydride, in carbonyl reductions, 9, 713—714... 

The reaction of l-allyl-l-(cyclohexyloxy)silacyclobutane with ct-hydroxy carbonyl compounds proceeded at a lower reaction temperature. The alkoxy group on silicon enhances the Lewis acidity of the allylsilacyclobutane and presents the possibility for ligand exchange to preceed the allylation event, which then occurs intramolecularly (Scheme 67). 

A transition state B (Scheme 11.8) has been proposed where the catalyst coordinates to silicon as a bidentate ligand through carbonyls and where H-bonding and n... n interactions are considered. A recent detailed report provided examples of the modifications of the structure of catalysts 19 and 20, the product configuration being controlled by the nature of the amino acid side chain. The replacement of i-Pr in 19 by Me leads to a reversal of configuration for the product 20, but this is obtained with a modest ee-value [26]. (For experimental details see Chapter 14.21.3). 

In all complexes of type Cp(OC)2Mn(H)SiR3 (and also PR3-substituted derivatives) the orientation of the silane relative to the Cp(OC)2Mn fragment is the same. If the Mn—H—Si triangle is taken as a reference plane, both carbonyl ligands are below this plane at about the same distance, one substituent at silicon (R1) is within this plane, and the other two substituents at silicon (R2) are above and below. The substituent R1 is the most electronegative one (in Fig. 2, the fluorine atom) how much this orientation of the silane is prone to steric effects has not yet been probed. 

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