Differentially Protected Diboron for Regioselective Diboration of Alkynes: Internal-Selective Cross-Coupling of 1-Alkene-1,2-diboronic Acid Derivatives

A differentially protected diboron bearing the naphthalene-1,8-diaminato group on one of the two boron atoms undergoes highly regioselective diboration with terminal alkynes in the presence of Pt or Ir catalysts, giving 1-alkene-1,2-diboronic acid derivatives in which the less reactive B(dan) group is located at the terminal position. The products undergo selective Suzuki-Miyaura coupling with aryl bromides at the internal boronyl group, leading to the formation of 2,2-disubstituted alkenylboronic acid derivatives.