A Simple Nickel Catalyst Enabling an E‐Selective Alkyne Semihydrogenation

Stereoselective alkyne semihydrogenations are attractive approaches to alkenes, which are key building blocks for synthesis. With regards to the most atom‐economic reducing agent dihydrogen (H(2)), only few catalysts for the challenging E‐selective alkyne semihydrogenation have been disclosed, each with a unique substrate scope profile. Here, we show that a commercially available nickel catalyst facilitates the E‐selective alkyne semihydrogenation of a wide variety of substituted internal alkynes. This results in a simple and broadly applicable overall protocol to stereoselectively access E‐alkenes employing H(2), which could serve as a general method for synthesis.