Abstract
Application of new reagents in the Z-selective synthesis of trisubstituted alkenes via modified Horner-Wadsworth-Emmons carbonyl olefination is presented. The reagents tested are ethyl bis(1,1,1,3,3,3-hexafluoroisopropyl)phosphonoalkanoates, structurally similar to Still-Gennari type reagents. A set of various trisubstituted Z-alkenes was obtained in very high or quantitative yields with excellent Z-selectivity. Remarkably, the procedure was very successful for the synthesis of Z-2-aryl-substituted cinnamic acid esters, maintaining exclusive Z-selectivity even at an increased temperature.