Pd-Catalyzed Addition of Arylboronic Acids to Alkynes Using O₂ as an Oxidant

Significance

Tetrasubstituted olefins have attracted a considerable amount of synthetic effort as they are an important class of compounds for medicinal chemistry and material science. The addition of arylboronic acids to alkynes is a convenient method for their preparation. The authors report a simple catalytic protocol for such a transformation which utilizes a Pd catalyst and oxygen as a reoxidant. To achieve good yields, the alkyne should bear an aryl or an electron-withdrawing group. Sterically hindered boronic acids give lower yields, vinylboronic acids lead to poor results. In general, the reaction is a quite convenient method for the synthesis of tetrasubstituted di- and triarylethylenes.