Chemoselective Multicomponent Synthesis of α,β‐Unsaturated Esters and Lactones and of Their Diels‐Alder Adducts

The “one‐pot reaction” of alcohols 1 (also chiral), aldehydes 2, and ketenylidenetriphenylphosphorane 3 yields α,β‐unsaturated esters 4 . With γ‐hydroxyaldehydes the reaction leads to formation of macrocyclic α,β‐unsaturated lactones. Four‐component reactions between 1, 2, 3 , and a diene lead immediately to Diels‐Alder adducts of 4 .