摘要 |
The invention relates to a process for the diastereoselective preparation of olefins via the Homer-Wadsworth-Emmons reaction, which consists in reacting at low temperature a phosphonate with a carbonyl derivative in the presence of a base in a suitable solvent, characterized in that a tris(polyoxaalkyl)amine sequestering reagent of formula (I): N-[CHR<SUB>1</SUB>-CHR<SUB>2</SUB>-O-(CHR<SUB>3</SUB>-CHR<SUB>4</SUB>-O)<SUB>n</SUB>-R<SUB>5</SUB>]<SUB>3 </SUB>(I), wherein: n is an integer between 0 and 10; R<SUB>1</SUB>, R<SUB>2</SUB>, R<SUB>3 </SUB>and R<SUB>4 </SUB>may be identical or different, and represent a hydrogen atom or an alkyl radical containing from 1 to 4 carbon atoms; R<SUB>5 </SUB>represents a hydrogen atom, an alkyl or cycloalkyl radical containing up to 12 carbon atoms, a phenyl radical or a radical of formula -CmuH2mu-Phi, or C<SUB>m</SUB>H<SUB>2m+1</SUB>-Phi-, with m being an integer between 1 and 12 and Phi being a phenyl radical; is added in an amount that is sufficient to increase the diastereoselectivity of the olefin.
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