Selective Palladium‐Catalyzed α,β‐Homodiarylation of Vinyl Esters in Aqueous Medium

Abstract

AbstractA palladium‐catalyzed 1,2‐diarylation of vinyl esters with arylboronic acids in water has been developed. This newly elaborated protocol features a good functional group tolerance and provides one‐step access to 1,2‐diarylethanol derivatives under mild reaction conditions. The presented reaction can be carried out in the water at ambient temperature without the addition of any ligands, what makes this procedure environmentally benign. The transformation occurs within a single catalytic cycle and is feasible due to the modification of transition metal catalytic activity through the influence of π‐acceptor olefin (benzoquinone) as well as water as a medium. Moreover, this protocol allows to generate entire compound libraries (highly profitable in medicinal chemistry) and utilizes sustainable arylboronic acids as coupling partners under mild conditions. It is also noted that the structure of boron moiety has a great impact on the reaction selectivity, the usage of sterically hindered esters of arylboronic acids influence the reaction course towards stilbenes.