Nickel-Catalyzed Coupling of N-Sulfonyl-1,2,3-triazole with H-Phosphine Oxides: Stereoselective and Site-Selective Synthesis of α-Aminovinylphosphoryl Derivatives.

A nickel-catalyzed coupling of N-sulfonyl-1,2,3-triazole with various H-phosphine oxides for the construction of C(sp2)-P bonds is established. This unexpected reaction proceeds through a formal nickel-bound ketenimine pathway, representing a previously unknown 1,2-reactivity type of an azavinyl carbene. The method provides an efficient approach to the stereoselective and site-selective synthesis of α-aminovinylphosphoryl derivatives with moderate to good yield. A plausible mechanism is proposed based on experimental and theoretical studies.