Cobalt‐Catalyzed Z‐Selective Hydrosilylation of Terminal Alkynes

A cobalt‐catalyzed Z‐selective hydrosilylation of alkynes has been developed relying on catalysts generated from bench‐stable Co(OAc)2 and pyridine‐2,6‐diimine (PDI) ligands. A variety of functionalized aromatic and aliphatic alkynes undergo this transformation, yielding Z‐vinylsilanes in high yields with excellent selectivities (Z/E ratio ranges from 90:10 to >99:1). The addition of a catalytic amount of phenol effectively suppressed the Z/E‐isomerization of the Z‐vinylsilanes that formed under catalytic conditions.