<i>Z</i>‑Selective Olefin Synthesis via Iron-Catalyzed Reductive Coupling of Alkyl Halides with Terminal Arylalkynes

Selective catalytic synthesis of <i>Z</i>-olefins has been challenging. Here we describe a method to produce 1,2-disubstituted olefins in high <i>Z</i> selectivity via reductive cross-coupling of alkyl halides with terminal arylalkynes. The method employs inexpensive and nontoxic catalyst (iron­(II) bromide) and reductant (zinc). The substrate scope encompasses primary, secondary, and tertiary alkyl halides, and the reaction tolerates a large number of functional groups. The utility of the method is demonstrated in the synthesis of several pharmaceutically relevant molecules. Mechanistic study suggests that the reaction proceeds through an iron-catalyzed <i>anti</i>-selective carbozincation pathway