Synthesis of Trisubstituted α,β-Unsaturated Esters through Catalytic Stereoretentive Cross-Metathesis

Abstract

We have devised a broadly applicable catalytic cross-metathesis method for stereoretentive synthesis of Z- and E-trisubstituted α,β-unsaturated esters. Several new Mo-bisaryloxide complexes were prepared, and they showed superior efficiency in synthesizing the Z-trisubstituted enoates (vs. corresponding mono-aryloxide pyrrolide complexes). Synthetic utility of the method was demonstrated through several concise syntheses of bioactive triterpenoids and value-added derivatives of prenyl-containing compounds such as citronellal, citronellol, and geraniol, all of which are isolated from essential oils. This transformation offers a valuable alternative to carbonyl olefination approaches such as Wittig and Horner-Wadsworth-Emmons reactions.