Investigations on the Suzuki−Miyaura and Negishi Couplings with Alkenyl Phosphates:  Application to the Synthesis of 1,1-Disubstituted Alkenes

The development of versatile Suzuki-Miyaura and Negishi cross-couplings with nonactivated alkenyl phosphates and aromatic boronic acids or organozinc reagents was achieved in acceptable to good yields. A series of 1,1-disubstituted alkenes were synthesized using a combination of either Ni(COD)2/Cy3P/K3PO4 or Pd2dba3/DPPF in THF. When working with alkenyl electrophiles in metal-catalyzed cross-couplings, this method lends itself as a less costly and more stable alternative to the corresponding triflate or nonaflate derivatives. In addition, initial studies are presented regarding an efficient 1,2-migration under Negishi coupling conditions.