Z-Selective Alkyne Functionalization Catalyzed by a -Dihydride N-Heterocyclic Carbene (NHC) Iron Complex.

The -selective functionalization of terminal alkynes is a useful transformation in organic chemistry and mainly catalyzed by noble metals. Here, we present the -selective hydroboration of terminal alkynes catalyzed by a stable -dihydride iron complex [(PCP)Fe(H)N)] (). Overall, the reaction occurs at room temperature and provides near quantitative yields of the -vinylboronate ester. Interestingly, the same catalyst could also provide the -vinylboronate by heating the reaction mixture at slightly elevated temperatures (50 °C). If, however, the reaction is performed in the absence of HBpin, rapid -selective alkyne dimerization is observed, which is further discussed in this report.