Pd‐Catalyzed Regioselective Olefination of N ‐Tosylhydrazones with Benzyl Bromides

A palladium‐catalyzed regioselective olefination of cycloalkylphenylmethylene N ‐tosylhydrazones and benzyl bromide was developed. A series of E ‐type tri‐substituted olefin compounds were obtained in 43–95% through the highly selective β ‐H elimination. The results showed that the β ‐H at the benzyl position took precedence over the β ‐H at the cycloalkyl position for the alkylpalladium intermediate, avoiding the formation of tetra‐substituted olefins. High regioselectivity, wide substrate scope, and good functional group tolerance are the advantages of this reaction.