Biomedical subjects

S Amrein

Publications and source records attributed to S Amrein.

3 recordsLinked to original sources

PubMed2001

Radical transfer hydrosilylation/cyclization using silylated cyclohexadienes.

[reaction: see text] A new method for mild metal-free hydrosilylation is described. Silylated cyclohexadienes are used as radical transfer hydrosilylating reagents for various double and triple bonds. A trialkylsilane is transferred from a cyclohexadiene moiety to an alkene. The hydrosilylation can be combined with a C-C bond formation as shown for the preparation of silylated cycloalkanes from the corresponding dienes.

Journal Article↗

PubMed2000

Silylated Cyclohexadienes: New Alternatives to Tributyltin Hydride in Free Radical Chemistry We are grateful to Prof. Dr. Dieter Seebach for generous financial support and to Prof. Dr. Erick M. Carreira for helpful discussions during the preparation of the manuscript. We also thank the Swiss Science National Foundation (2100-055280.98/1) for funding our work.

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Journal Article↗

PubMed2000

Stereoselective radical aryl migration from silicon to carbon.

Highly diastereoselective radical 1,5 phenyl migration reactions from silicon in diarylsilyl ethers to various C-centered radicals to form the corresponding 3-phenylated alcohols are described. Functionalized aryl groups can also be transferred. The effect of the variation of the attacking radical on the aryl transfer reaction is discussed. Best results are obtained for the phenyl migration to nucleophilic secondary alkyl radicals, where high yields (up to 81%) and high selectivities (up to 95% ds) have been obtained. The mechanism of the process is discussed and a model to explain the stereochemical outcome of the reaction is presented. Finally, stereoselective 1,4 aryl migration reactions from Si to C, including a new method for the alpha-arylation of esters, are presented.

Alcohols↗