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

• Published in: European journal of organic chemistry 2020-04, Vol.2020 (14), p.2052-2061
• Main Authors: Hachem, Mahmoud, Schneider, Cédric, Hoarau, Christophe
• Format: Article
• Language: English
• Subjects: Alkenes; Aromatic compounds; Benzoic acid; Benzoic acid derivatives; Carboxylates; Carboxylic acids; Catalysis; Chemical Sciences; Cross‐coupling; Decarboxylation; Ethers; Homogeneous catalysis; Organic chemistry; Stereoselectivity; Substrates; Synthesis design; Vinyl ethers
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201901877

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. 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 family of attractive β‐arylated α‐alkoxy α,β‐unsaturated carboxylates, which is a relevant class of building blocks with different applications.