Ligand‐Controlled Stereodivergent Manganese‐Catalyzed Hydroalkoxylation of Alkynylnitriles to Access (E)‐ and (Z)‐3‐Alkoxyvinylnitriles

Abstract Precise stereocontrol over functionalized alkenes remains a central challenge in organic synthesis. In particular, catalytic methods enabling flexible and stereodivergent synthesis of both trans ‐selective and cis ‐selective useful enol ethers are still underdeveloped. Herein, we report a manganese‐catalyzed, ligand‐controlled hydroalkoxylation of alkynylnitriles with alcohols under mild conditions. Through metal–ligand cooperation, a range of ( Z )‐ and ( E )‐3‐alkoxyvinylnitriles were obtained in high yields and with excellent selectivity by simply tuning the steric properties of PNP‐pincer ligands: bulkier t Bu PNP–Mn catalyst favored Z ‐selectivity, while less hindered i Pr PNP–Mn catalyst led to E ‐selectivity. This method features a broad substrate scope, high functional group tolerance and exceptional chemo ‐, regio ‐, and stereo ‐selectivity. Mechanistic studies revealed that Z ‐products are initially formed in both cases, with the i Pr PNP–Mn catalyst further promoting isomerization to the thermodynamically favored E ‐isomers.