Theoretical Studies on Iron‐Catalyzed Enantioselective Hydrogenation of Alkenes

ABSTRACT The metal‐catalyzed enantioselective hydrogenation of olefins is one of the most powerful methods for preparing optically active compounds. Based on the iron‐catalyzed highly enantioselective hydrogenation of alkenes, we conducted detailed theoretical calculations utilizing density functional theory (DFT) methods. The three‐step mechanism involves alkene insertion, silane‐mediated metathesis, and hydrogen‐mediated metathesis. The two‐step mechanism consists solely of alkene insertion and hydrogen‐mediated metathesis. Both pathways are energetically accessible. In both mechanisms, alkene insertion acts as the rate‐limiting and stereodetermining step. Moreover, the role of MeCN is of significant importance, as it may inhibit the 2,1‐insertion and β ‐H elimination. The calculations reveal that the chiral ligand with S configuration controls enantioselectivity, leading to a strong preference for the R enantiomer due to the stronger interaction energy and lower steric hindrance.