Pd(0)‐Catalyzed Cross‐Coupling of Allyl Halides with α‐Diazocarbonyl Compounds or N‐Mesylhydrazones: Synthesis of 1,3‐Diene Compounds.

With palladium catalysis, allyl bromides or chlorides react with α-diazocarbonyl compounds or N-mesylhydrazones to afford 1,3-diene derivatives. The reaction represents a novel and efficient method for the synthesis of 1,3-butadiene derivatives. Mechanistically, the reaction is proposed to follow a pathway involving the formation of a π-allylic palladium carbene complex and subsequent migratory insertion.