Pinacol silyl ethers

A pinacol-type silylative dimerization of various aromatic aldehydes promoted by a cationic thiolate-bridged diruthenium complex has been reported by Flidai and co-workers (Equation (28)).344 l,2-Diaryl-l,2-disiloxyethanes 153 were isolated as the major products along with the corresponding arylmethyl silyl ethers as minor products. 

In a final example, summarized in Scheme 2.7.4, Herscovici, et al.,120 utilized several silyl ethers in reactions with various glycals to prepare the products shown. In the same report, a study was carried out involving the use of deuterated allylic ethers. This experiment, shown in Scheme 2.7.5, was designed to prove the involvement of a pinacole-type mechanism in the transformation. The 1,2-deuteride shift supported this hypothesis. 

A pinacol-type rearrangement of epoxy silyl ethers has been used to prepare 0-hydroxy ketones, the migratory aptitudes observed... 

Later research on diradical C-C initiators [174,175] focused on oligomeric silyl pinacol ethers (20) which were used to prepare PS-co-polysiloxane block copolymers. 

Phophonate Pinacol coupling Reductive deconjugation Ring-opening oxidation Silyl enol ether Silyl ketene acetal Tautomerism Vanadium bromoperoxidase Vanadium catalyst Vinyl phosphonate... 

Such polymerizations were also reported with other thermal iniferters such as highly substituted ethanes and silyl pinacole ethers. It was shown [91] that sterically hindered carbon—carbon single bonds such as those found in hexaphenylethane were easily thermally cleaved to produce trityl radicals. Subsequently, it was found that the tetraarylethane and benzpinacole could also decompose in the same way and could be used [92,93] as initiators for... 

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