Condition-Controlled Divergent Selective Synthesis of (<i>Z</i>)-<i>N</i>-Vinyl and <i>N</i>-Allenyl Benzimidazoles by Pd- or Bi-Catalyzed Direct <i>N</i>-Alkenylation Reactions

We have developed a condition-controlled divergent synthesis of (<i>Z</i>)-<i>N</i>-vinyl and <i>N</i>-allenyl benzimidazoles from 1,1,3-triphenylprop-2-yn-1-ols and benzimidazoles through Pd- or Bi-catalyzed <i>N</i>-alkenylation reactions involving nucleophilic attack and C-C bond cleavage processes. The desired two different kinds of products can be conveniently and selectively synthesized by using this strategy, which features stereospecific synthesis, good functional group tolerance, a broad substrate scope, and high efficiency. The strategy provides significant advantages for the synthesis of biologically and pharmaceutically active imidazoheterocycles.