Synthesis of o ‐Allyloxy(ethynyl)benzene Derivatives by Cu‐Catalyzed Suzuki–Miyaura‐Type Reaction and Their Transformations into Heterocyclic Compounds

We have found that Suzuki–Miyaura‐type reactions of o ‐allyloxy(bromoethynyl)benzenes with arylboronic acids using a hydrazone/Cu catalyst system proceeded smoothly in i PrOH under mild conditions to afford the corresponding o ‐allyloxy(arylethynyl)benzene derivatives in good yields without decomposition of the allyloxy group. We have further demonstrated that annulation and enyne metathesis of the o ‐allyloxy(arylethynyl)benzene derivatives using transition‐metal catalysts led to various heterocyclic compounds.