Synthetic applications of (E)-α-trialkylsilyl-α,β-unsaturated esters
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Abstract
This dissertation details the use of (E)-α-trialkylsilyl-α,β-unsaturated esters for three novel methodologies. This document is divided into four chapters. The first chapter will relate pertinent background information about enolates and extended dienolates that will be revisited in subsequent chapters. The second chapter will recount a γ-deprotonation-α-protonation sequence resulting in (E)-α-trialkylsilyl-β,γ- unsaturated esters. It explores potential reasons for poor a-regioselective protonations present in the literature. The intermediate extended dienolate was also trapped which allowed for confirmation of its stereochemistry. A method to transform (Ε)-α-trialkylsilyl-α,β-unsaturated esters into chiral allyl silanes will be examined in the third chapter. This will involve a Cu(I) catalyzed conjugate addition involving Grignard reagents followed by a diastereoselective protonation. This is important because α-silyl-α,β-unsaturated esters have a scant record in the literature as Michael acceptors. Finally, the last chapter will relate the culmination of work performed in chapter two and direct application of ideas presented in chapter one, which consists of using the extended dienolate with known sterochemistry for a tandem diastereoselective aldol- Peterson olefination process. These methodologies will provide much needed light on the synthetic utility of (E)-α-trialkylsilyl-α,β-unsaturated esters.