Direct Stereoselective β‐Arylation of Enol Ethers by a Decarboxylative Heck‐Type Reaction

Abstract

Despite remarkable advances to promote regio‐ and stereoselective decarboxylative arylation of inactivated olefins with benzoic acid derivatives, methodologies involving hetero‐substituted alkenes are still lacking. Herein, PdII‐catalyzed decarboxylative Heck coupling of α‐alkoxyacrylates with (hetero)aryl carboxylic acids for the stereocontrolled production of (Z)‐β‐heteroarylated vinyl ethers is reported. This methodology offers a rational and step‐economical route to the synthesis of attractive β‐arylated α‐alkoxy α,β‐unsaturated carboxylates family which emerged as a relevant class of building blocks with different applications. Mechanistically, whereas electron rich benzoic acids undergo a PdII‐catalyzed decarboxylation, electron‐deficient substrates proceed through silver(I)‐mediated decarboxylation, explaining thus the formation of stereoisomers (E) and (Z) of β‐arylated vinyl ethers in presence of these latter.