Silanols, reaction with palladium complexes

The analysis of silanolate order with a stoichiometric amount of palladium with respect to 2-iodothiophene also revealed a first-order dependence of reaction rate on silanolate concentration. This critical experiment rules out the possibility that an activated complex involving another molecule of silanolate (with i to generate a pentacoordinate silicon) is formed. In the latter case, second-order behavior would have been expected. 

An asymmetric variant of this reaction was developed using chiral Pd complex 111 with either silanes or disiloxanes [66-68]. Both relative and absolute stereochemistries were controlled in this system and good yields (60-85%) were obtained after oxidation (Eq. 18). Formation of the silane-containing product was inhibited by the presence of water due to competitive formation of the palladium hydrides and silanols [68]. The use of disiloxanes as reductants, however, provided expedient oxidation to the alcohol products without decreasing the isolated yields enantioselectivity was 5-15% lower in this more robust system [66]. Benzhydryldimethylsilane proved to be a good compromise between high yield and facile oxidation [66]. Palladium com-... 

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