Gold‐Catalyzed Cycloaddition Reactions of Ethyl Diazoacetate, Nitrosoarenes, and Vinyldiazo Carbonyl Compounds: Synthesis of Isoxazolidine and Benzo[b]azepine Derivatives

Gold‐catalyzed cycloadditions of ethyl diazoacetate, nitrosoarenes, and vinyldiazo carbonyl species to yield isoxazolidine derivatives stereoselectively are described. Treatment of these isoxazolidine products with the same catalyst results in a novel 1,2‐H shift/[3,3] rearrangement to give benzo[b]azepine compounds. The mechanism of this skeletal rearrangement is elucidated with deuterium‐labeling experiments.