Palladium(0)-Catalyzed Highly Regio- and Stereoselective Addition of Organoboronic Acids with 1,2-Allenylphosphonates Forming Tri- or Tetrasubstituted 1( E )-Alkenylphosphonates

A highly regio- and stereoselective palladium(0)-catalyzed addition of organoboronic acids with 1,2-allenylphosphonates in the presence of HOAc forming tri- or tetrasubstituted 1(E)-alkenylphosphonates is reported in this paper. The stereoselectivity is much higher than the reported cases. The effects of different R(1), R(2), and R(3) were studied. A mechanism of this reaction is proposed on the basis of our previous study.