Two-carbon homologation of ketones via sily ketene acetals: Synthesis of α, β-unsaturated acids and α-trimethylsilyl δ-ketoacids

M Bellassoued, S Mouelhi, P Fromentin…

Index: Bellassoued, Moncef; Mouelhi, Sinda; Fromentin, Pierre; Gonzalez, Aurelien Journal of Organometallic Chemistry, 2005 , vol. 690, # 9 p. 2172 - 2179

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Citation Number: 7

Abstract

The reaction of C, O, O-tris (trimethylsilyl) ketene acetal 1 with saturated, cyclic and aromatic ketones 2 proceeds smoothly in the presence of titanium chloride to give (E)-α, β- unsaturated carboxylic acids 3 with fairly good stereoselectivity. With α, β-unsaturated ketones 4, α-trimethylsilyl δ-ketoacids 5 (syn+ anti) are obtained according to Michael-type 1, 4 addition. These diastereoisomers are separated and the configurations of 5a are ...