ORGN 507 |
| Carbon-silicon bonds have fundamental roles in organic synthesis, for example, as control groups for stereochemistry in chemical reactions, or as surrogates to introduce the hydroxyl function (Tamao-Fleming oxidation). Typically establishing the carbon-silicon configuration in the beta-position to a carbonyl group serves a complementary of making enantiomerically pure aldol fragments. One of the most important pathways to form carbon-silicon bonds is conjugate silylation to unsaturated carbonyl compounds by nucleophilic silyl reagents. In the hitherto known reagents, silylzincates become one of most potential candidates because of theirs good stability, solubility and reasonable reactivity. Useful protocols based on those reagents are needed to be further developed to fulfill the fine organic synthesis requirements. Herein, we reported the conjugate addition of α,β-unsaturated carbonyl compounds with a bissilylzincate as well as monosilylzincate reagents. The efficiency of the those reagents and the importance of copper(É) catalysts will be reported. Both good chemical yield and high diastereomeric ratio (dr) products were obtained for the conjugate addition of various asymmetric substrates. The conjugate addition to various á,â-unsaturated aldehydes and esters were also investigated. Those methodologies should be considered as useful, reliable protocols to introduce silyl functionalities to α,β-unsaturated carbonyl compounds. |
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New Reactions and Methodology, Heterocycles and Aromatics, Bioorganic Chemistry
8:00 PM-10:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Division of Organic Chemistry |